ORCID Profile
0000-0002-7999-660X
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 03-2006
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.JCIS.2014.09.082
Abstract: In this report, various iron-based nanoparticles (nZVI, n-Ni/Fe, n-Pd/Fe) were used for both heterogeneous Fenton oxidation of 2,4-dichlorophenol (2,4-DCP) and reductive dechlorination of 2,4-DCP in order to understand their roles in the Fenton oxidation and the reductive degradation of 2,4-DCP. The dechlorination efficiency of 2,4-DCP using nZVI, n-Ni/Fe, n-Fe/Pd and Fe(2)(+) was 6.48%, 6.80%, 15.95%, 5.02%, while Fenton oxidation efficiency of 2,4-DCP was 57.87%, 34.23%, 27.94%, 19.61% after 180 min, respectively. The new findings included a higher dechlorination using n-Fe/Pd due to Pd effective catalysis and the effective heterogeneous Fenton oxidation using nZVI depending on reductive dechlorination and heterogeneous Fenton oxidation occurs simultaneously. However, nZVI as the potential catalyst for heterogeneous Fenton was observed, and SEM, EDS and XRD demonstrate that change on the nZVI surface occurred due to the Fe(2+) leaching, and Total Organic Carbon (TOC) (30.71%) shows that 2,4-DCP was degraded. Furthermore, the experiment indicates that the pH values and concentration of 2,4-DCP significantly impacted on the heterogeneous Fenton oxidation of 2,4-DCP and the data fits well with the pseudo first-order kinetic model, which was a diffusion-controlled reaction. Finally, a possible mechanism for degradation of 2,4-DCP was proposed.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.CHEMOSPHERE.2016.11.092
Abstract: Bio-synthesis of Fe NPs in inert (nitrogen N-Fe NPs) and oxygen (O-Fe NPs) atmospheres employing green tea extracts was investigated through SEM, EDS, XPS and FT-IR techniques. The particle sizes of N-Fe NPs and O-Fe NPs were confirmed by SEM showing 84.7 ± 11.5 nm and 117.8 ± 26.2 nm respectively with subsequent evaluation of the percentage composition of Fe and O by EDS. The XPS results showed that the zero-valent iron and iron oxide nanoparticles were found to be dominant synthesized respectively in nitrogen and oxygen atmospheres. The FT-IR spectra further demonstrated that the surface functional groups of Fe NPs were different by varying the synthesis atmosphere. Fe NPs were used to remove methylene blue (MB) to test the reactivity, and the removal efficiency of MB using N-Fe NPs was 98.7%, while that of O-Fe NPs was only 65.3%. Thus it is clearly demonstrated that the synthesis atmosphere has prominent effects on the formation and catalytic properties of Fe NPs.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 10-2010
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.TALANTA.2014.08.010
Abstract: Sodium potassium absorption ratio (SPAR) is an important measure of agricultural water quality, wherein four exchangeable cations (K(+), Na(+), Ca(2+) and Mg(2+)) should be simultaneously determined. An ISE-array is suitable for this application because its simplicity, rapid response characteristics and lower cost. However, cross-interferences caused by the poor selectivity of ISEs need to be overcome using multivariate chemometric methods. In this paper, a solid contact ISE array, based on a Prussian blue modified glassy carbon electrode (PB-GCE), was applied with a novel chemometric strategy. One of the most popular independent component analysis (ICA) methods, the fast fixed-point algorithm for ICA (fastICA), was implemented by the genetic algorithm (geneticICA) to avoid the local maxima problem commonly observed with fastICA. This geneticICA can be implemented as a data preprocessing method to improve the prediction accuracy of the Back-propagation neural network (BPNN). The ISE array system was validated using 20 real irrigation water s les from South Australia, and acceptable prediction accuracies were obtained.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.COLSURFB.2018.09.008
Abstract: A multifunctional biomaterial capable of simultaneously removing malachite green (MG) and Cr(VI) was prepared by immobilizing Burkholderia cepacia (B. cepacia) on eucalyptus leaves (EL). The maximum uptake of MG (60 mg/L) and Cr(VI) (20 mg/L) were 94.8% and 71.9% respectively, which was more efficient than when using EL or free cells alone. SEM-EDS demonstrated that B. cepacia was attached to EL and that Cr(VI) was biosorbed into the immobilized cells. FTIR showed that the degradation by functional groups of immobilized cells was in keeping with the products, detected by GC-MS, which suggested that MG could be degraded to 4-dimethylamino benzophenone and 4-dimethylamino phenol. The removal of both MG and Cr(VI) by EL immobilized cells fit the pseudo-second order adsorption kinetic model well (with both R
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.ENVPOL.2018.01.100
Abstract: This study examined functional bentonite-supported nanoscale Fe/Ni (B-Fe/Ni) for the simultaneous removal of β-lactam antibiotics such as amoxicillin (AMX), icillin (AMP) and penicillin (PEN). The results show only 94.6% of AMX, 80.6% of AMP and 53.7% of PEN were removed in the mixed antibiotic solution, while 97.5% of AMX, 85.1% of AMP and 74.5% of PEN were removed in in idual antibiotic solution. The decreased removal in a mixed antibiotic solution was attributed to competition between antibiotics for: firstly, active sites of iron oxide for the adsorption and secondly, accepted electrons for the degradation in passivation of the nZVI surface. These were confirmed by various characterization techniques. Kinetics studies of mixed antibiotics using B-Fe/Ni confirmed that adsorption and degradation occurred simultaneously as removing of antibiotics in the presence of particles. Furthermore, the stability and durability of B-Fe/Ni applied to remove β-lactam antibiotics was demonstrated. Finally, B-Fe/Ni was used to reduce the concentration of mixed antibiotics from pharmaceutical wastewater, which indicated B-Fe/Ni is a promising material for antibiotics wastewater treatment.
Publisher: Elsevier BV
Date: 10-1996
Publisher: Wiley
Date: 07-1998
DOI: 10.1002/(SICI)1521-4109(199807)10:8<567::AID-ELAN567>3.0.CO;2-O
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 02-2023
DOI: 10.1016/J.JCIS.2022.11.074
Abstract: The widespread use of antibiotics, such as oxytetracycline (OTC) and levofloxacin (LEV), has led to dangerous levels of environmental contamination. In this study, functionalized iron/manganese nanoparticles (Fe/Mn NPs), which act as both adsorbent and Fenton catalyst, were green-synthesized using a reducing agent derived from a tea extract. The resulting pre-sorption/Fenton-like oxidation system effectively removed both OTC and LEV from the aqueous solution with adsorption capacities of Fe/Mn NPs for OTC and LEV of 58.8 and 192.3 mg·g
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA08808E
Abstract: Biomolecules in plant extracts are often used to reduce metal ions to nanoparticles in a single-step green synthesis process that is environment friendly and sustainable.
Publisher: Georg Thieme Verlag KG
Date: 21-04-2023
DOI: 10.1055/S-0043-57245
Abstract: Objective This study aimed to investigate the effect of relining prefabricated fiber-reinforced composite (FRC) posts using bulk-fill, flowable, discontinuous short fiber-reinforced composite (SFRC) on intracanal adaptation in weakened endodontically-treated premolar teeth. Materials and Methods Forty extracted human premolar teeth were selected and randomly allocated to five groups (n = 8) according to the canal preparation method and restorative technique after endodontic treatment: Group 1 (control): nonflared, closed apex root canals group 2, 4: flared, open-apex root canals group 3, 5: flared, closed apex root canals. Groups 1 to 3 were restored with standard RelyX fiber post size #1, while groups 4 and 5 were restored with customized RelyX fiber post size #1 and relined with bulk-fill flowable SFRC (everX Flow, GC, Tokyo, Japan). To evaluate intracanal adaptation, the empty root of each s le with the corresponding fiber post (standard or customized) inserted was measured twice using a micro-digital scale and the average value was calculated. The post was then removed, followed by the insertion of a light body polyvinyl siloxane (PVS) impression material into the canal, followed by reinsertion of the post and removal of excess material once the PVS was set. Finally, the s le weight was recorded, and the data were analyzed using one-way analysis of variance and the Bonferroni post hoc test (p-value = 0.05). Results A statistically significant difference (p 0.05) in PVS material weight was identified between the groups. Group 1 (control) had the lightest weight of PVS material, followed by groups restored with customized fiber posts (groups 4 and 5) and standard fiber posts (groups 2 and 3). Conclusion Anatomically-customized fiber posts with bulk-fill flowable SFRC provided better intracanal adaptation compared with standard fiber posts in teeth with compromised root canals.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.CHEMOSPHERE.2014.02.045
Abstract: Nitrate contamination in drinking water is a major threat to public health. This study investigated the efficiency of denitrification of aqueous solutions in the co-presence of synthesized nanoscale zero-valent iron (nZVI diameter: 20-80 nm) and a previously isolated Paracoccus sp. strain YF1. Various influencing factors were studied, such as oxygen, pH, temperature, and anaerobic corrosion products (Fe(2+), Fe(3+) and Fe3O4). With slight toxicity to the strain, nZVI promoted denitrification efficiency by providing additional electron sources under aerobic conditions. For ex le, 50 mg L(-1) nZVI increased the nitrate removal efficiency from 66.9% to 85.2%. However, a high concentration of nZVI could lead to increased production of Fe(2+), a toxic ion which could compromise the removal efficiency. Kinetic studies suggest that denitrification by both free cells, and nZVI-amended cells fitted well to the zero-order model. Temperature and pH are the major factors affecting nitrate removal and cell growth, with or without the presence of nZVI. In this study, nitrate removal and cell growth increased in the pH range of 6.5-8.0, and temperature range of 25-35 °C. These conditions favor the growth of the strain, which dominated denitrification in all scenarios involved. As for anaerobic corrosion products, compared with Fe(2+) and Fe(3+), Fe3O4 promoted denitrification by serving as an electron donor. Finally, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) confirmed attachments of nZVI on the surface of the cell, and the formation of iron oxides. This study indicated that, as an electron donor source with minimal cellular toxicity, nZVI could be used to promote denitrification efficiency under biotic conditions.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2015
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.TALANTA.2015.07.044
Abstract: This study introduced a patented novel methodological system for automatically analysis of Fourier Transform Infrared Spectrometer (FTIR) spectrum data located at 'fingerprint' region (wavenumber 670-800 cm(-1)), to simultaneously determinate multiple petroleum hydrocarbons (PHs) in real mixture s les. This system includes: an object oriented baseline correction Band decomposition (curve fitting) method with mathematical optimization and Artificial Neural Network (ANN) for determination, which is suitable for the characteristics of this IR regions, where the spectra are normally with low signal to noise ratio and high density of peaks. BTEX components are potentially lethal carcinogens and contained in many petroleum products. As a case study, six BTEX components were determinate automatically and simultaneously in mixture vapor s les. The robustness of the BTEX determination was validated using real petroleum s les, and the prediction results were compared with gas chromatography-mass spectrometry (GC-MS).
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 02-2023
Publisher: American Chemical Society (ACS)
Date: 05-01-2018
Abstract: In an effort to advance the understanding of multiamine based CO
Publisher: American Chemical Society (ACS)
Date: 09-08-2016
Publisher: Elsevier BV
Date: 07-2018
Publisher: Wiley
Date: 1997
DOI: 10.1002/(SICI)1098-2728(1997)9:4<201::AID-LRA6>3.0.CO;2-4
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.JHAZMAT.2012.06.029
Abstract: Paracoccus sp. strain YF1 immobilized on bamboo carbon was developed for the denitrification. The results show that denitrification was significantly improved using immobilized cells compared to that of free cells, where denitrification time decreased from 24h (free cells) to 15 h (immobilized cells). The efficiency of denitrification increased from 4.57 mg/(Lh) (free cells) to 6.82 mg/(Lh) (immobilized cells). Kinetics studies suggest that denitrification by immobilized YF1 cells fitted well to the zero-order model. Scanning electron microscopy (SEM) demonstrated that firstly, the bacteria became stable on the inside and exterior of the bamboo carbon particles and secondly, they formed biofilm after adhesion. Various factors and their influences on biological denitrification were investigated, namely temperature, pH, initial nitrate concentrations and carbon sources. The immobilized cells exhibited more nitrate removal at various conditions compared to free cells since bamboo carbon as a carrier protects cells against changes in environmental conditions. Denitrification using the YF1 immobilized in bamboo carbon was also maintained 99.8% after the tenth cycle reuse, thus demonstrating excellent reusability. Finally, wastewater was treated using the immobilized cells and the outcome was that nitrogen was completely removed by bamboo-immobilized YF1.
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.CHEMOSPHERE.2022.137021
Abstract: The co-existence of contaminants such as triclosan (TCS) and Cadmium in wastewater is a major public health problem because of their persistence and toxicity. In this study, bio-reduced graphene oxide (B-rGO) synthesized by Lysinibacillus sp. Simultaneously remove TCS and Cd(II), with adsorption capacities of 81.91 and 23.32 mg g
Publisher: Wiley
Date: 08-2000
DOI: 10.1002/1521-4168(20000801)23:7/8<511::AID-JHRC511>3.0.CO;2-6
Publisher: Elsevier BV
Date: 15-05-2009
DOI: 10.1016/J.TALANTA.2008.12.052
Abstract: Ion-pairing chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) used for the speciation of phosphorus is limited as the mobile phase containing organic solvents changes in detection sensitivity and the carbon precipitates on torch and cones. To address this issue, anion-exchange chromatography with ICP-MS has been used for the speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts. The separation of the targets on a new column was achieved within 5 min using an eluent containing 20 mM NH(4)NO(3) at pH 5.1. Furthermore, since the polyatomic ions such as (14)N(16)O(1)H(+) and (15)N(16)O(+) from a nitrogen-based ion-pairing reagent interfered with ICP-MS detection of (31)P, an octopole reaction system was investigated to determine whether the polyatomic interferences could be reduced. The results show that addition of He to the cell can benefit analyses by reducing such interferences, but at the expense of reduced sensitivity. The detection limits in the range of 1.0-1.5 microg L(-1) (expressed as P) was achieved when 50 microL was injected using He as the collusion gas.
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 03-2018
Publisher: Wiley
Date: 12-11-2013
Publisher: Elsevier BV
Date: 07-2015
Publisher: Elsevier BV
Date: 03-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 1997
DOI: 10.1039/A700771J
Publisher: Elsevier BV
Date: 02-2022
Publisher: Informa UK Limited
Date: 1998
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.BIORTECH.2013.03.018
Abstract: The Bacillus fusiformis (BFN) strain and its biodegradation of phenol when iron-based nanoparticles such as nanoscale zero-valent iron (nZVI) and Ni/Fe nanoparticles (Ni/Fe) were present at different pH values (6.0, 8.0, and 3.0) were investigated. The growth of BFN and its biodegradation of phenol accelerated in the presence of nZVI and Ni/Fe both at pH 8.0 and pH 6.0. The H2 generated by the corrosion of iron can be used as an electron donor and source of energy for growing BFN. However, only nZVI improved the biodegradation of phenol at pH 3.0, which is most likely due to the increasing medium pH value resulting from the generation of OH(-) as a result of iron corrosion. The images from scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) demonstrated that these iron-based nanoparticles adhered to the surface of BFN, but no significant change in the morphology of BFN was observed.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 04-2014
Publisher: Elsevier BV
Date: 2020
DOI: 10.1016/J.JCIS.2019.09.106
Abstract: Green synthesis of nanoparticles is becoming increasingly popular as a simple and environmentally friendly method. In this study, iron-based nanoparticles (Fe-NPs) were successfully prepared using a peanut skin extract, where the peanut skin as an agricultural waste product was easy to obtain in large quantities, relatively inexpensive and also environmentally friendly. The average particle size of the produced Fe-NPs changed with their post-synthesis drying conditions. Under vacuum drying at 60 °C, the smallest average particle size obtained was 10.6 nm. The synthesized Fe-NPs had a core shell-like structure, in which the core was composed of Fe
Publisher: Elsevier BV
Date: 2019
DOI: 10.2139/SSRN.3365719
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.MSEC.2017.08.073
Abstract: In this paper, iron oxide nanoparticles (IONPs) are successfully synthesized using Eucalyptus leaf extract in the presence of cetyltrimethylammonium bromide (CTAB) to enhance the dispersion and reduce aggregation of IONPs. CTAB was used as a stabilizing and capping agent in biosynthesis of IONP was observed. The particle size decreased from 183.9±30.1nm to 89.8±17.1nm as the concentration of CTAB increased from 0 to 0.4mM CTAB, indicating that CTAB reduce the aggregation of IONPs and enhance the reactivity. In addition, the removal efficiency of phosphate declined from 95.13% to 89.58% when the CTAB concentration increased from 0.4 to 10mM, indicating that a CTAB impacted on micelles and lipophilic biomolecules in Eucalyptus leaf extract, and hence affected the formation of IONPs. Furthermore, SEM image showed that the smaller spherical with some irregularly shaped CTAB-IONPs having a diameter of 80-90nm in the presence of 0.4mM CTAB were observed. The date from EDS, FTIR and TGA suggested that the CTAB capped on the surface of CTAB-IONPs, while XRD showed that zero-valent iron and iron oxide were formed. Finally, the formation mechanism of IONPs was proposed.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.JHAZMAT.2015.04.027
Abstract: Biomolecules taken from plant extracts have often been used in the single-step synthesis of iron-based nanoparticles (Fe NPs) due to their low cost, environmental safety and sustainable properties. However, the composition of Fe NPs and the degradation mechanism of organic contaminants by them are limited because these are linked to the reactivity of Fe NPs. In this study, Fe NPs synthesized by grape leaf extract served to remove Orange II. Batch experiments showed that more than 92% of Orange II was removed by Fe NPs at high temperature based on adsorption and reduction and confirmed by kinetic studies. To understand the role of Fe NPs in the removal process of azo dye, surface analysis via X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed, showing that the Fe NPs were composed of biomolecules, hydrous iron oxides and Fe(0), thus providing evidence for the adsorption of Orange II onto hydrous iron oxides and its reduction by Fe(0). Degraded products such as 2-naphthol were identified using LC-MS analysis. A degradation mechanism based on asymmetrical azo bond cleavage for the removal of Orange II was proposed.
Publisher: American Chemical Society (ACS)
Date: 28-03-2003
DOI: 10.1021/JF025978P
Abstract: Hydrolysis of an insecticide/nematicide, fenamiphos [ethyl-3-methyl-4-(methylthio)phenyl-(1-methylethyl)phosphoramidate], immobilized through sorption by cetyltrimethylammonium-exchanged montmorillonite (CTMA-clay) by a soil bacterium, Brevibacterium sp., was examined. X-ray diffraction analysis, infrared spectra, and a negative electrophoretic mobility strongly indicated that fenamiphos was intercalated within the bacterially inaccessible interlayer spaces of CTMA-clay. The bacterium hydrolyzed, within 24 h, 82% of the fenamiphos sorbed by the CTMA-clay complex. There was a concomitant accumulation of hydrolysis product, fenamiphos phenol, in nearly stoichiometric amounts. During the same period, in abiotic (uninoculated) controls, 4.6% of the sorbed insecticide was released into the aqueous phase as compared to 6.0% of the sorbed fenamiphos in another abiotic control where activated carbon, a sink for desorbed fenamiphos, was present. Thus, within 24 h, the bacterium hydrolyzed 77% more fenamiphos sorbed by organo clay than the amounts desorbed in abiotic controls. Such rapid degradation of an intercalated pesticide by a bacterium has not been reported before. Evidence indicated that extracellular enzymes produced by the bacterium rapidly hydrolyzed the nondesorbable fenamiphos, even when the enzyme itself was sorbed. Fenamiphos strongly sorbed to an organo clay appears to be readily available for exceptionally rapid degradation by the bacterium.
Publisher: Wiley
Date: 20-06-2018
DOI: 10.1002/JCTB.5328
Publisher: Elsevier BV
Date: 15-12-2005
DOI: 10.1016/J.TALANTA.2005.09.011
Abstract: The performance of capillary electrophoresis-ultraviolet detector (CE-UV), hydride generation-atomic absorption spectrometry (HG-AAS) and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) have been compared for the speciation of arsenic (As) in groundwater s les. Two inorganic As species, arsenite (As(III)), arsenate (As(V)) and one organo species dimethyl arsenic acid (DMA) were mainly considered for this study as these are known to be predominant in water. Under optimal analytical conditions, limits of detection (LD) ranging from 0.10 (As(III), AsT) to 0.19 (DMA) mug/l for HG-AAS, 100 (As(III), DMA) to 500 (As(V)) mug/l for CE-UV and 0.1 (DMA, MMA) to 0.2 (As(III), As(V)) mug/l for LC-ICP-MS, allowed the determination of the above three species present in these s les. Results obtained by all the three methods are well correlated (r(2)=0.996*** for total As) with the precision of <5% R.S.D. except CE-UV. The effect of interfering ions (e.g. Fe(2+), Fe(3+), SO(4)(2-) and Cl(-)) commonly found in ground water on separation and estimation of As species were studied and corrected for. Spike recovery was tested and found to be 80-110% at 0.5mug/l As standard except CE-UV where only 50% of the analyte was recovered. Comparison of these results shows that LC-ICP-MS is the best choice for routine analysis of As species in ground water s les.
Publisher: Mary Ann Liebert Inc
Date: 04-2016
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.CHEMOSPHERE.2013.11.033
Abstract: Despite bimetallic Fe/Ni nanoparticles have been extensively used to remediate groundwater, they have not been used for the catalytic degradation of amoxicillin (AMX). In this study, bentonite-supported bimetallic Fe/Ni (B-Fe/Ni) nanoparticles were used to degrade AMX in aqueous solution. More than 94% of AMX was removed using B-Fe/Ni, while only 84% was removed by Fe/Ni at an initial concentration of 60 mg L(-1) within 60 min due to bentonite serving as the support mechanism, leading to a decrease in aggregation of Fe/Ni nanoparticles, which was confirmed by scanning electron microscopy (SEM). The formation of iron oxides in the B-Fe/Ni after reaction with AMX was confirmed by X-ray diffraction (XRD). The main factors controlling the degradation of AMX such as the initial pH of the solution, dosage of B-Fe/Ni, initial AMX concentration, and the reaction temperature were discussed. The possible degradation mechanism was proposed, which was based on the analysis of degraded products by liquid chromatography-mass spectrometry (LC-MS).
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.CHEMOSPHERE.2022.135778
Abstract: Since antimony (Sb) is a toxic metalloid cost-effective method for the simultaneous removal of the two major Sb species from mining wastewater has attracted much attention. In this study, phytosynthesized iron nanoparticles (nFe) prepared using a eucalyptus leaf extract were successfully used to simultaneously remove Sb(III) and Sb(V) via an adsorption and oxidation mechanism with removal efficiencies of 100 and 97.7% for Sb(III) and Sb(V), respectively. Advanced analysis using X-ray photoelectron spectroscopy (XPS), ion chromatography-atomic fluorescence spectroscopy (IC-AFS), and electrochemical analysis confirmed that Sb(III) was oxidized to Sb(V) by Fe(III) on the nFe surface while Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) indicated that both Sb(III) and Sb(V) were adsorbed onto nFe. Adsorption of both Sb(III) and Sb(V) best fit the Langmuir adsorption model with R
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.JCIS.2014.08.011
Abstract: Adsorption of anionic dye - Orange II - in aqueous solution onto hexadecyltrimethylammonium bromide (HDTMA)-coated zeolite (HCZ) reached 38.96mg/g compared with 8.13mg/g onto natural zeolite. Fourier Transform Infrared (FTIR), scanning electronic microscopy (SEM) and X-ray powder diffraction (XRD) data showed that HDTMA-coated zeolite developed surficial positive charges. The adsorption reaction fits the Freundlich isotherm (R(2)=0.93) and the value of 1/n was less than unity (=0.81) and suggest a multi-layer physi-sorption process. The kinetics of the adsorption is a pseudo-second-order model. The activation energy (Ea) of the reaction is +35.70kJ/mol to further support a physi-sorption process while the ΔH(o) (+82.79kJ/mol) is characteristic for an endothermic reaction. The ΔG(o) values of -2.33, -0.98 and -0.37kJ/mol at 25°C, 30°C and 35°C, respectively implied that the adsorption reaction was feasible and thermodynamically spontaneous. We proposed that both electrostatic interactions and partitioning process are involved in the adsorption mechanisms of Orange II dye onto HCZ.
Publisher: Springer Science and Business Media LLC
Date: 17-08-2012
DOI: 10.1007/S10532-012-9580-7
Abstract: This study evaluated the potential of monitored natural attenuation (MNA) as a remedial option for groundwater at a long-term petroleum hydrocarbon contaminated site in Australia. Source characterization revealed that total petroleum hydrocarbons (TPH) as the major contaminant of concern in the smear zone and groundwater. Multiple lines of evidence involving the geochemical parameters, microbiological analysis, data modelling and compound-specific stable carbon isotope analysis all demonstrated natural attenuation of hydrocarbons occurring in the groundwater via intrinsic biodegradation. Groundwater monitoring data by Mann-Kendall trend analysis using properly designed and installed groundwater monitoring wells shows the plume is stable and neither expanding nor shrinking. The reason for stable plume is due to the presence of both active source and natural attenuation on the edge of the plume. Assuming no retardation and no degradation the contaminated plume would have travelled a distance of 1,096 m (best case) to 11,496 m (worst case) in 30 years. However, the plume was extended only up to about 170 m from its source. The results of these investigations provide strong scientific evidence for natural attenuation of TPH in this contaminated aquifer. Therefore, MNA can be applied as a defensible management option for this site following significant reduction of TPH in the source zone.
Publisher: Elsevier BV
Date: 03-2015
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 04-2006
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 06-2016
Publisher: Springer Science and Business Media LLC
Date: 21-11-2008
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.CHEMOSPHERE.2017.12.073
Abstract: The increasing production of graphene raised concerns about their releasing into sewage sludge, however, there is little information about graphene impacting on the growth of bacteria and hence their bioleaching of metal ions from sewages sludge. In this study, we reported that Acidithiobacillus sp., isolated from sewages, were used to bioleach Cu
Publisher: Informa UK Limited
Date: 2001
Publisher: Elsevier BV
Date: 02-2015
Publisher: Informa UK Limited
Date: 05-2019
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.JCIS.2012.05.035
Abstract: The degradation of Scarlet 4BS (4BS) in aqueous solution using Fe/Ni nanoparticles was investigated in this paper. Batch experiments show that the degradation of 4BS depended on an initial dye concentration, the solution pH and total Fe/Ni concentration and reaction temperature. The removal of 84.5% of 4BS was achieved when the solution contained 100 mg/L of 4BS under optimal conditions, including an 8.0 g/L nanoscale Fe/Ni, pH 5.0, 30 °C for 3 h. In addition, a kinetics study indicates that the degradation of 4BS was well suited to the pseudo-first-order model, where the apparent rate constant (K(obs)) was 6.3×10(-3) min(-1). Moreover, XRD indicated that no iron and nickel oxide formed after Fe/Ni nanoparticles reacted to 4BS. However, data from FTIR show that new bands appeared which corresponding to CH after 4BS reacted with the Ni/Fe nanoparticles. A degradation mechanism is proposed here where iron was oxidized, the hydrogen being produced was adsorbed on the catalytic nickel surface, 4BS reductively by degrading two cleaving the azo linkages. This application has much potential in that 71.2% of 4BS was removed from wastewater.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.SCITOTENV.2015.05.044
Abstract: To investigate the effect of nanoscale zero-valent iron (nZVI) on the growth of Paracoccus sp. strain and biodenitrification under aerobic conditions, specific factors were studied, pH, concentration of nitrate, Fe (II) and carbon dioxide. Low concentration of nZVI (50mg/L) promoted both cell growth and biodegradation of nitrate which rose from 69.91% to 76.16%, while nitrate removal fell to 67.10% in the presence of high nZVI concentration (1000 mg/L). This may be attributed to the ions produced in nZVI corrosion being used as an electron source for the biodegradation of nitrate. However, the excess uptake of Fe (II) causes oxidative damage to the cells. To confirm this, nitrate was completely removed after 20 h when 100mg/L Fe (II) was added to the solution, which is much faster than the control (86.05%, without adding Fe (II)). However, nitrate removal reached only 45.64% after 20 h, with low cell density (OD 600=0.62) in the presence of 300 mg/L Fe (II). Characterization techniques indicated that nZVI adhered to microorganism cell membranes. These findings confirmed that nZVI could affect the activity of the strain and consequently change the biodenitrification.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.MSEC.2018.12.145
Abstract: Since Fe
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.JCIS.2013.02.020
Abstract: Kaolinite-supported nanoscale zero-valent iron (K-nZVI) was successfully synthesized as a multifunctional composite and used for the degradation of crystal violet (CV). The presence of kaolinite not only decreased the aggregation of zero-valent iron nanoparticles (nZVI) with maintenance of reactivity, but also facilitated reaction by increasing the local concentration of CV in the vicinity of nZVI as an adsorbent. This was confirmed by scanning electron microscopy (SEM) and batch experiments, which showed that 97.23% of CV was removed using K-nZVI, while only 78.72% and 39.22% of CV were removed using nZVI and kaolinite after 30 min, respectively. Different factors impacting on degradation of CV were investigated as well. On the basis of these results, a removal mechanism was proposed including: (i) prompt adsorption of CV to the K-nZVI phase, and (ii) reduction of CV by Fe(0) on K-nZVI. Furthermore, different adsorption and reduction kinetics were employed to examine the removal process of CV, where a better fit with the pseudo-second-order model for adsorption and pseudo-first-order model for reduction process was observed, and reduction was the rate limiting step. In addition, isotherm and thermodynamic parameters were evaluated for a specific study of the important adsorption step. Finally, the application of K-nZVI to treat wastewater showed the removal efficiency higher than 99.9%.
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.JES.2016.01.015
Abstract: Mg-Al-Cl layered double hydroxide (Cl-LDH) was prepared to simultaneously remove Cu(II) and Cr(VI) from aqueous solution. The coexisting Cu(II) (20mg/L) and Cr(VI) (40mg/L) were completely removed within 30min by Cl-LDH in a dosage of 2.0g/L the removal rate of Cu(II) was accelerated in the presence of Cr(VI). Moreover, compared with the adsorption of single Cu(II) or Cr(VI), the adsorption capacities of Cl-LDH for Cu(II) and Cr(VI) can be improved by 81.05% and 49.56%, respectively, in the case of coexisting Cu(II) (200mg/L) and Cr(VI) (400mg/L). The affecting factors (such as solution initial pH, adsorbent dosage, and contact time) have been systematically investigated. Besides, the changes of pH values and the concentrations of Mg
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.CHEMOSPHERE.2018.11.181
Abstract: Graphene is usually synthesized through deoxygenation of graphene oxide (GO) by hydrazine which functions as a reducing agent, but the production of graphene via this method suffers a high cost and is often regarded to be not environmental-friendly. In this work, we developed a simple and efficient method for the green reduction of GO to reduced graphene oxide (rGO) dispersed on sugarcane bagasse derived from rGO/bagasse material. The rGO/bagasse was characterized by Scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, Thermogravimetric analysis, X-ray photoelectron spectroscopy and X-ray diffraction analysis. All these characterization techniques clearly revealed that the rGO has been successfully prepared by reduction sugars. In addition, rGO synthesized from bagasse was considered as a promising adsorbent for removing methyl blue. Adsorption kinetics were also applied to stimulate the adsorption process, and the adsorption behavior of this new adsorbent fits well with the pseudo-second-order kinetic model (R
Publisher: Elsevier BV
Date: 03-2013
Publisher: Informa UK Limited
Date: 09-1998
Publisher: Desalination Publications
Date: 2017
Publisher: American Chemical Society (ACS)
Date: 22-10-2018
Abstract: The high energy requirement of amine regeneration and the uncertainty of safe disposal of the captured CO
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 03-2023
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.SAA.2014.08.116
Abstract: This study investigates green tea extract synthesized conditions impacting on the reactivity of iron nanoparticles (Fe NPs) used for the degradation of malachite green (MG), including the volume ratio of Fe(2+) and tea extract, the solution pH and temperature. Results indicated that the reactivity of Fe NPs increased with higher temperature, but fell with increasing pH and the volume ratio of Fe(2+) and tea extract. Scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), Fourier transform infrared spectroscope (FTIR) and X-ray diffraction (XRD) indicated that Fe NPs were spherical in shape, their diameter was 70-80 nm and they were mainly composed of iron oxide nanoparticles. UV-visible (UV-vis) indicated that reactivity of Fe NPs used in degradation of MG significantly depended on the synthesized conditions of Fe NPs. This was due to their impact on the reactivity and morphology of Fe NPs. Finally, degradation of MG showed that 90.56% of MG was removed using Fe NPs.
Publisher: Elsevier BV
Date: 03-2022
DOI: 10.1016/J.CHEMOSPHERE.2021.132777
Abstract: Even a small concentration of estrogen released into the environment can cause great damage to the surrounding ecosystem, with potential teratogenic and carcinogenic hazards to many organisms. In this study, carbonized green synthesized Fe/Ni NPs, with a maximum adsorption capacity of 44.32 mg g
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.SCITOTENV.2019.136308
Abstract: While a one-step green synthesis of a hybrid material composed of reduced graphene oxide and bimetallic Fe/Pd nanoparticles (RGO@Fe/Pd NPs) was previously successfully reported and evaluated for the removal of organic contaminants, the relationship between the formation of RGO@Fe/Pd and the resulting reactivity was unclear. In this paper the impact of the specific synthetic conditions on the reactivity of RGO@Fe/Pd was investigated in order to enhance the removal efficiency of antibiotics such as rif icin. The hybrid material (RGO@Fe/Pd) successfully removed 96.1% of rif icin compared to only 63.5 and 81.0% for Fe nanoparticles and RGO, respectively. The best synthetic conditions for the formation of RGO@Fe/Pd included GO/Fe = 1:1 and Fe/Pd = 100: 5. In addition, GC-MS and FTIR were used to identify the main reducing biomolecules in the green tea extract responsible for the one-step synthesis of RGO@Fe/Pd as Catechol, Caffeine, 1,3,5-Benzenetriol. The morphology, size and surface composition of RGO@Fe/Pd was characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-Ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These advanced characterization techniques suggested that during synthesis GO was initially converted to RGO, and thereafter Fe/Pd NPs (10-50 nm) were dispersed on RGO. Finally, a plausible formation mechanism for the one-step synthesis of the hybrid material was proposed.
Publisher: Elsevier BV
Date: 08-2001
DOI: 10.1016/S0021-9673(01)01116-5
Abstract: A simple method was developed for the simultaneous determination of Cr(III) and Cr(VI) by capillary zone electrophoresis (CZE), where Cr(III) was chelated with ligands to form anionic complexes. Nitrilotriacetic acid, N-2-hydroxyethylenediaminetriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and 2,6-pyridinedicarboxylic acid (PDCA) were investigated as Cr(III) complexing ligands. Of all the ligands studied, 2,6-PDCA with Cr(III) gave the largest UV response and high selectivity for Cr(III). In addition, the condition for pre-column derivatization, including pH, concentration ratio [Cr(III)/2,6-PDCA] and the stability of Cr(III) complexes were also examined. The separation of anionic forms of Cr(III) and Cr(VI) was achieved using co-CZE with UV detection at 185 nm. The electrolyte contained 30 mM phosphate, 0.5 mM tetradecyltrimethylammonium bromide, 0.1 mM 2,6-PDCA and 15% (v/v) acetonitrile at pH 6.4. The detection limits were 2 microM for Cr(III) and 3 microM for Cr(VI) and linear plots were obtained in a concentration range of 5-200 microM. The utility of the method was demonstrated for the determination of Cr(III) and Cr(VI) in contaminated soils.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.SCITOTENV.2018.12.391
Abstract: While phytogenic nanomaterials have been successfully used to remove heavy metals in wastewater, the potential to successfully use such materials to immobilize heavy metals in soils is still unclear. In this study, phytogenic iron oxide nanoparticles (PION) were used to immobilize cadmium (Cd) in six soils. Amendment with PION effectively immobilized Cd, with a concomitant increase in the concentrations of iron oxides, soil pH and dissolved organic carbon (DOC) under both oxic and anoxic conditions. However, observed changes in soil properties and Cd fractions were different under oxic and anoxic conditions. After PION application, the exchangeable Cd fraction decreased by up to 91 and 69%, while the carbonate bound Cd fraction decreased by up to 61 and 75%, under oxic and anoxic conditions, respectively. Pearson correlation analysis revealed that under both oxic and anoxic conditions, Cd fractions were significantly and positively correlated with free iron oxide content and pH, where free iron oxide content was positively correlated with amorphous iron oxide, DOC and pH. The Cd immobilization mechanisms potentially involved either (1) formation of insoluble hydroxides at elevated pH (2) participation of biomolecules released from PION in ligand complexation with Cd and (3) co-precipitated of Cd during the formation of iron oxides. This study provided new insights into the potential effects of PION applications for practical Cd immobilization in contaminated soils.
Publisher: Elsevier BV
Date: 11-2022
Publisher: Wiley
Date: 22-09-2010
DOI: 10.1002/RCM.4737
Abstract: Stable complexes are required during the ion chromatographic (IC) separation of Fe-polycarboxylic acid complexes. Electrospray ionization mass spectrometry (ESI-MS) was used to identify 1:1 stoichiometric complexes of Fe[HEDTA], Fe[EDTA](1-) and Fe[DTPA](2-), and the spectra showed that these Fe complexes were stable in solution. Furthermore, inductively coupled plasma mass spectrometry (ICP-MS) using an octopole reaction system (ORS) reduced polyatomic ion (40)Ar(16)O(+) interference in the detection of (56)Fe via the addition of either H(2) or He to the ORS, with He at a flow rate 3.5 mL min(-1) being the optimum collision gas. Finally, IC/ICP-MS was used for the separation and detection of Fe complexes with an eluent containing 30 mM (NH(4))(2)HPO(4) at pH 8.0, but only Fe[HEDTA], Fe[EDTA](1-) and Fe[DTPA](2-) were observed within 10 min with reasonable resolution. Detection limits in the range of 10-13 µg L(-1) were achieved using He as the collision gas. The proposed method was used for the determination of Fe species in soil solutions.
Publisher: Springer Science and Business Media LLC
Date: 07-2003
DOI: 10.1007/S00216-003-1956-4
Abstract: This paper reports a new method for preconcentration and separation of trace amounts of molybdenum in seawater s les prior to determination by inductively coupled plasma-atomic emission spectroscopy (ICP-OES). Diethylenetriaminetetraacetic acid-functionalized polysiloxane (DETAP) was synthesized by carboxymethylation of amino groups on triamine immobilized polymer, which was prepared by modification of 3-chloropropylpolysiloxane with diethylenetriamine. The resulting polysiloxane is highly selective and efficient in chelating Mo(VI) at trace levels. It can be used as a column packing material. The polysiloxane column can be reused over ten times without losing its original properties, so it is suitable for preconcentration of molybdenum species in seawater s les before determination. The parameters governing the characteristics of polysiloxane for adsorption of Mo(VI) were investigated. These include the effect of pH, amount of polysiloxane, equilibrium time, adsorption isotherm, maximum adsorption capacity, interfering ions, flow rate, capacity for reuse, and desorption. The precision of the preconcentration method, calculated as the relative standard deviation of seawater s les, was 3%. The preconcentration factor was 100. The detection limit, defined as 3 times the standard deviation of five replicate measurements of the blank s le at pH 3, was 0.17 microg L(-1). Measurement results for standard reference materials were in good agreement with the certified values [(CRMs), NASS-2 Seawater (Open Ocean) and CASS-2 Seawater (Coastal)].
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.CHEMOSPHERE.2017.11.057
Abstract: Improving the anode configuration to enhance biocompatibility and accelerate electron shuttling is critical for efficient energy recovery in microbial fuel cells (MFCs). In this paper, green reduced graphene nanocomposite was successfully coated using layer-by-layer assembly technique onto carbon brush anode. The modified anode achieved a 3.2-fold higher power density of 33.7 W m
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 05-2019
Publisher: Elsevier BV
Date: 11-1998
DOI: 10.1016/S0039-9140(98)00170-2
Abstract: A flow injection analysis of Ca(2+) and Mg(2+) using indirect potentiometric detection in natural waters is proposed, where Ca(2+) or Mg(2+) are injected into a buffer carrier containing phosphate, resulting in the formation of Ca(3)(PO(4))(2) or Mg(3)(PO(4))(2). The consequent reduction in free phosphate in the carrier solution is detected using a metallic cobalt wire electrode. Indirect electrode response was used and the experimental conditions affecting electrode response were optimized. Responses were linear in the concentration range 5x10(-4) to 5x10(-3) M with a detection limit of 1x10(-5) M in 20 mM phosphate buffer at pH 8.0. The relative standard derivation at 1 mM of Ca(2+) and Mg(2+) were 3.9 and 3.7% (n=10), respectively. EGTA and 8-hydroxyquinoline were used as the masking agents for Ca(2+) and Mg(2+), respectively. Concentrations of Ca(2+) and Mg(2+) in natural waters were successfully determined by the proposed method.
Publisher: Elsevier BV
Date: 2002
DOI: 10.1016/S0021-9673(01)01402-9
Abstract: Co-electroosmotic capillary zone electrophoresis (CZE) with direct UV detection was developed for simultaneous determination of inorganic anions, carboxylic and aromatic carboxylic acids. These solutes were separated using a 30 mM phosphate buffer containing 1.0 mM tetradecyltrimethylammonium bromide (TTAB) and 20% (v/v) acetonitrile at pH of 6.5 and directly detected by UV at 190 nm. Calibration curves were linear in the range 0.01-2.0 mM, depending of the solutes. The detection limits ranged from 1.0 to 8.0 microM and the relative standards deviations (n=5) in range from 1.9 to 3.6% for the peak area. The proposed method was used to determine inorganic anions and carboxylic and aromatic acids in soil and plant tissue extracts.
Publisher: Elsevier BV
Date: 09-2023
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.MARPOLBUL.2011.06.002
Abstract: Edible marine products (n=24) collected from the fish markets in Adelaide, Australia, were analysed for the presence of polybrominated diphenyl ethers (PBDEs). The total concentration of 11 PBDE congeners found in the marine products ranged from 1.01 to 45 ng/g fresh weight. Among the s les analysed, imported silver fish and prawns from Vietnam and Thailand respectively, recorded the highest ∑PBDEs concentrations (45.10 and 43.29 ng/g fresh weight) as against 13.08 and 12.57 ng/g fresh weight in Australian king prawns and Gar fish. BDE-209 was the most dominant congener in the marine products followed by BDE-47, 99 and 100. The calculated average daily intakes of ∑PBDEs per day for an adult male and female (19 or more years old) were 1026.8 and 1188.4 ng/kg per day, respectively. This study clearly shows that the dietary exposure to marine foods can contribute to PBDEs accumulation in human body.
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.CHEMOSPHERE.2014.03.058
Abstract: With a dramatic rise in complexity, needs of nanotoxicology research go beyond simple forms of nanomaterials. This study compared the phototoxicity of nano-TiO2 and graphene-TiO2 nanocomposite (GNP). GNP was synthesized based on a hydrothermal method, which simultaneously performed the reduction of graphene oxide and nano-TiO2 loading. A series of acute toxicity tests of nano-TiO2, graphene and GNP was performed on two aquatic organisms, Daphnia magna and Oryzias latipes. Fast and substantial agglomeration and sedimentation of nanoparticles in test media and surface attachment of nano-TiO2 and GNP on D. magna surface was observed. Similar phototoxicity of nano-TiO2 and GNP for both species existed, though compared with nano-TiO2, GNP had a 2.3-fold increase in visible light photocatalytic ROS generation. In summary, this study demonstrated the significance of illumination spectrum, particle behavior, and species sensitivity on nanophototoxicity, and the needs for research on increasingly sophisticated functional materials.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JHAZMAT.2018.12.047
Abstract: In this paper, a Zeolite Imidazole Framework-8 (ZIF-8), was investigated for the removal of a mixture of two common antibiotics, tetracycline (TC) and oxytetracycline hydrochloride (OTC). Batch experiments showed that 90.7% of TC and 82.5% of OTC were simultaneously removed using ZIF-8. The maximum adsorption capacities for TC and OTC were 303.0 and 312.5 mg g
Publisher: Springer Science and Business Media LLC
Date: 10-2002
DOI: 10.1007/S00216-002-1456-Y
Abstract: An on-column complexation method has been developed for the simultaneous determination of V(IV) and V(V). Vanadium species were chelated with aminopolycarboxylic acids to form anionic complexes which were separated by capillary zone electrophoresis (CZE) with direct UV detection. Ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentacetric acid (DTPA), nitrilotriacetic acid (NTA), and N-2-hydroxyethylethlendiaminetriacetric acid (HEDTA) were investigated as both ligand and running electrolyte. Of the ligands studied the complexes of EDTA with V(IV) and V(V) resulted in the highest selectivity and UV response. The conditions used for on-column complexation and separation, including pH, and electrolyte ligand concentration, were examined to achieve reasonable separation selectivity and detection sensitivity. The optimum separation of the anionic forms of V(IV) and V(V) was obtained by use of CZE with UV detection at 185 nm and an electrolyte containing 5 mmol L(-1) EDTA at pH 4.0. Linear calibration plots were obtained in the concentration range10-300 micro mol L(-1) detection limits were 3 micro mol L(-1) for V(IV) and 1 micro mol L(-1) for V(V). The proposed method was demonstrated for the determination of vanadium in groundwater spiked with V(IV) and V(V).
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.JES.2015.07.016
Abstract: Toxicity studies considering both the bare and stabilized forms of zero valent iron nanoparticles (nZVI) could be timely, given that ecological risks identified are minimized through modification or with substitution of approaches in the synthesis, development and environmental application of the nanoparticles before succeeding to volume production. This review is focused on the fate, transport and toxicological implications of the bare nZVI and surface modified particles used for environmental applications.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.JCIS.2019.09.058
Abstract: While nanomaterials are increasingly being proposed for contaminant remediation, a major challenge is how to develop high removal functionality while maintaining low cost and environmental friendliness. In this study, a hybrid reduced graphene oxide/iron nanoparticle (rGO/Fe NPs) was prepared via the in situ reduction of GO and FeCl
Publisher: Elsevier BV
Date: 03-2010
Publisher: Wiley
Date: 07-1999
DOI: 10.1002/(SICI)1521-4168(19990701)22:7<379::AID-JHRC379>3.0.CO;2-G
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.ENVPOL.2019.04.002
Abstract: Biosynthesis of nanoparticles using plant extract is one kind of the effective approach in developing rapid, clean, nontoxic, and eco-friendly technology. In this work, iron nanoparticles/reduced graphene oxide composites (Fe NPs/rGO) were facilely fabricated through one-step method with eucalyptus leaf extract. The synthesized Fe NPs/rGO was investigated by various characterization methods. SEM results disclosed that Fe NPs with regular spherical shape of 70 ± 10 nm was uniformly dispersed on rGO. A basal plane of rGO with high surface area, providing more load sites for Fe NPs, which was confirmed by TEM. XRD and FTIR results indicated that biomolecules from eucalyptus extract were capped on Fe NPs/rGO. The EDS mapping showed that Fe NPs dispersed evenly on rGO, and XPS further confirmed that Fe NPs/rGO composite was mainly comprised with Fe NPs and rGO. Furthermore, the biomolecules of eucalyptus leaf extract were identified by GC-MS to confirm that alcohol phenols acted as reducing agent, while alcohol acids and ketones acted as capping agents. In addition, the removal efficiency of Methylene blue (MB) up to 93% with Fe NPs/rGO. This work provides a simple, green cost-effective and environmentally friendly method to fabricate metal/rGO composite.
Publisher: Informa UK Limited
Date: 08-2013
Publisher: American Chemical Society (ACS)
Date: 17-04-2004
DOI: 10.1021/JF035173X
Abstract: The role of algae in the persistence, transformation, and bioremediation of two endocrine disrupting chemicals, alpha-endosulfan (a cyclodiene insecticide) and its oxidation product endosulfan sulfate, in soil (incubated under light or in darkness) and a liquid medium was examined. Incubation of soil under light dramatically decreased the persistence of alpha-endosulfan and enhanced its transformation to endosulfan sulfate, over that of dark-incubated soil s les, under both nonflooded and flooded conditions. This enhanced degradation of soil-applied alpha-endosulfan was associated with profuse growth of indigenous phototrophic organisms such as algae in soil incubated under light. Inoculation of soil with green algae, Chlorococcum sp. or Scenedesmus sp., further enhanced the degradation of alpha-endosulfan. The role of algae in alpha-endosulfan degradation was convincingly demonstrated when these algae degraded alpha-endosulfan to endosulfan sulfate, the major metabolite, and endosulfan ether, a minor metabolite, in a defined liquid medium. When a high density of the algal inoculum was used, both metabolites appeared to undergo further degradation as evident from their accumulation only in small amounts and the appearance of an endosulfan-derived aldehyde. Interestingly, beta-endosulfan was detected during degradation of alpha-endosulfan by high density algal cultures. These algae were also capable of degrading endosulfan sulfate but to a lesser extent than alpha-endosulfan. Evidence suggested that both alpha-endosulfan and endosulfan sulfate were immediately sorbed by the algae from the medium, which then effected their degradation. Biosorption, coupled with their biotransformation ability, especially at a high inoculum density, makes algae effective candidates for remediation of alpha-endosulfan-polluted environments.
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.ECOENV.2012.06.017
Abstract: The strain, Burkholderia vietnamiensis C09V was immobilized on PVA-alginate-kaolin gel beads as a biomaterial to improve the degradation of crystal violet from aqueous solution. The results show that 98.6% (30 mg L(-1)) crystal violet was removed from aqueous solution using immobilized cells on PVA-alginate-kaolin gel beads, while 94.0% crystal violet was removed by free cells after degradation at the pH 5 and 30°C for 30 h. Kinetics studies show that the pseudo-second-order kinetics well described the adsorption of crystal violet on the PVA-alginate-kaolin beads. Biodegradation of crystal violet on immobilized cells was fitted well by first-order reaction kinetics, indicating that CV was adsorbed onto kaolin and followed their degradation by immobilized cells onto the the PVA-alginate-kaolin beads. Characterization with SEM shows that cells attached well to the surface of PVA-alginate-kaolin beads, leading to improved crystal violet transfer from aqueous solution to immobilized cells. In addition, UV-vis show that the absorption peak at 588 nm was reduced by the degraded N-bond linkages, as well as the formation of degrading products were observed by Fourier transform infrared (FTIR). These results suggest that crystal violet was biodegraded to N,N-dimethylaminophenol and Michler's Ketone prior to these intermediates being further degraded.
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.CHROMA.2014.09.086
Abstract: Inductively coupled plasma-mass spectrometry (ICP-MS) and electrospray mass spectrometry (ESI-MS) were used as complementary methods to identify Sn-pentaacetic acid (DTPA) complex formation. ESI-MS was used to initially confirm the formation of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) and their MS spectra suggest these tin complexes were stable in solution. On-column complexation of tin with DTPA and the separation of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) was performed on anion-exchange chromatography with an mobile phase containing 20mM NH4NO3 and 3mM DTPA at pH 6.0, and the subsequent detection of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) was achieved by ICP-MS. Linear plots were obtained in a concentration range of 1.0-1000 μg L(-1) with detection limits ranging from 0.1 to 0.3 μg L(-1). The developed procedure allows the simultaneous determination of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) in less than 5 min with a RSD between 2.1 and 2.7%. The recoveries of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) were found to be 96.8 and 99.4%, respectively, when the s le was spiked with 20 μg L(-1) standard. Finally, the proposed procedure was used for the determination of tin species in contaminated water.
Publisher: Elsevier BV
Date: 05-1995
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.JCIS.2022.05.150
Abstract: Due to its low-cost, eco-friendliness and easy mode of separation biosynthesized magnetic ferroferric oxide (Fe
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.JCIS.2020.01.014
Abstract: A nFe@ZIF-8 composite, which combined the tailorable porosity of ZIF-8 with the versatile functionality of Fe nanoparticles (nFe), was synthesized for Pb(II) removal. Batch adsorption experiments showed that more than 95.3% of Pb(II) was removed from aqueous solution at an initial concentration of 50 mg L
Publisher: Elsevier BV
Date: 11-2017
Publisher: Wiley
Date: 04-1997
Publisher: Elsevier BV
Date: 06-2022
Publisher: Wiley
Date: 23-02-2018
Publisher: Wiley
Date: 31-08-2007
Abstract: Reversed-phase liquid chromatography with UV detection is of limited applicability in the separation and identification of carboxylic acids because of the column's poor separation efficiency and the non-selective nature of the UV detector. To address this issue, RP-LC with electrospray ionization mass spectrometry has been explored for the confirmation and determination of carboxylic acids in plant root exudates, with ESI-MS providing structural information, high selectivity, and high sensitivity. The separation of 10 carboxylic acids (pyruvic, lactic, malonic, maleic, fumaric, succinic, malic, tartaric, trans-aconitic, and citric acid) was performed on a C(18) column using an eluent containing 0.1% (v/v) acetic acid within 10 min, where the acidic eluent not only suppressed the ionization of the carboxylic acids to be retained on the column, but was also compatible with ESI-MS detection. In addition, an additional standard was used to overcome the matrix effect. The results showed that peak areas correlated linearly with the concentration of carboxylic acids over the range 0.05-10 mg/L. The detection limits of target acids (signal-to-noise S/N ratio of 3) ranged from 20 to 30 microg/L. Finally, the proposed method was used for the confirmation and determination of low-molecular-weight carboxylic acids in plant root exudates, and provided a simple analytical procedure, including s le processing, fast separation, and high specificity and sensitivity.
Publisher: Elsevier BV
Date: 05-1998
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.JENVMAN.2013.08.032
Abstract: Organobentonites used as absorbents to remove amoxicillin from wastewater have been investigated here because they are effective in removing organic pollutants. It is evident that bentonite modified with hexadecyl trimethyl ammonium (DK1) can effectively remove amoxicillin from aqueous solution. Batch experiments showed that the adsorption of amoxicillin onto DK1 fitted well to a pseudo second-order kinetic model with corresponding rate constants (0.0187 g/mg min at 20 °C). The Langmuir isotherm provided the highest adsorption capacity (26.18 mg/g at 20 °C). Our thermodynamic study suggested that the adsorption of amoxicillin onto DK1 was physisorptive and endothermic in nature. Furthermore DK1 was characterized by scanning electronic microscopy (SEM), Specific Surface Area (SSA), X-ray powder diffraction (XRD) and Fourier Transform Infrared (FTIR) spectrometer. These characterizations provided evidence of the morphological properties and how well the adsorption process performed. An adsorption mechanism including both ion-exchange and partition was proposed. Finally, DK1 was used to remove amoxicillin from wastewaters and the results showed 81.9% and 87.5% of amoxicillin was removed at 19.0 mg/L and 2.0 mg/L, respectively.
Publisher: Elsevier BV
Date: 11-2023
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.ACA.2006.12.008
Abstract: Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time. Electrospray mass spectrometry (ES-MS) was used to confirm the formation of [VO(2)(HEDTA)](2-) and [VO(HEDTA)](1-) in solution. An electrolyte containing 25 mM phosphate, 0.25 mM tetradecyltrimethylammonium bromide (TTAB) at pH 5.5 was optimum for the separation of these anionic vanadium complexes. S le stacking techniques, including large-volume s le stacking (LVSS) and field- lified s le injection (FASI), were tested to improve the sensitivity. Best sensitivity was obtained using FASI, with detection limits of 0.001 microM, equivalent to 0.4 microg L(-1), for [VO(2)(HEDTA)](2-) and 0.01 microM, equivalent to 3.4 microg L(-1) for [VO(HEDTA)](1-). The utility of the method for the speciation of V(IV) and V(V) was demonstrated using ground water s les.
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.JENVMAN.2022.115224
Abstract: Plant-mediated synthesis of silver nanoparticles (Ag NPs) is a green and economically viable method, which can offer numerous benefits over traditional chemical and physical methods. In this paper, three fruit extracts (tomato, orange, and grapefruit) served simultaneously as stabilizing and reducing agents during the biosynthesis of Ag NPs. The formation of Ag NPs, were monitored using the UV-visible absorption spectra of Ag NPs which exhibited three distinct bands centered at 439, 413, and 410 nm. SEM and TEM analysis indicated that these bands corresponded to three distinct spherical-shaped Ag NPs having average particle sizes of 73, 24, and 31 nm, respectively. XRD and EDS spectral analyses were used to verify the degree of crystallinity, nanostructure, and presence of Ag NPs. Advanced analysis using XPS, FTIR, and GC-MS indicated that the Ag NPs were coated with a variety of organic compounds including acids, aldehydes, esters, and ketones, indicating that fruit derived phytochemicals had a significant role in synthesis, and subsequently a mechanism of Ag NPs formation was proposed. The fabricated nanoparticles were also successfully used in Fenton-like oxidation for the environmental remediation of estrone and estriol, with removal efficiencies of 52.1 and 35.9%, respectively.
Publisher: Springer Science and Business Media LLC
Date: 30-03-2016
Publisher: Informa UK Limited
Date: 2004
Publisher: Elsevier BV
Date: 09-2017
Publisher: Elsevier BV
Date: 08-2023
Publisher: Edith Cowan University
Date: 07-2016
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.SCITOTENV.2018.01.241
Abstract: The advantages of green synthesized iron nanoparticles by plant extracts include simplicity, high efficiency and sustainability. However, there are limitations in our understanding of the formation of Fe NPs. In this report, the synthesized iron nanoparticles by eucalyptus leaf extract (Fe NPs) showed that Cr(VI) removal efficiency reached approximately 100% at volume ratio of leaf extract and iron(III) solution of 2:1 and pH 4. In addition, the morphology, surface and compositions of Fe NPs were characterized by various techniques. The diameter distribution of 95 ± 5 nm with a capping layer was observed, containing polyphenols and aliphatic acids confirmed by FTIR and XRD. XPS indicated that Fe NPs contained iron oxides, as well as a layer covering on Fe NPs created by biomolecules from eucalyptus leaf extract. Furthermore, the biomolecules identified by GC-MS indicated that alcohol phenols and alkylaldehyde acted as reducing agents, while alcohol acids, alkanols, phytols, acetate and aromatic ketones acted as capping agents. It can be concluded that aldehydes, phenols and alcoholic compounds played dominant roles during the synthesis of Fe NPs. Finally, the mechanism for the formation of Fe NPs was proposed, including both that of Fe NPs and capped Fe NPs.
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.CHEMOSPHERE.2022.137198
Abstract: While the availability of arsenic (As) in soil is well known to be highly correlated with the presence of iron (Fe) oxides and humic acid (HA) in the soil, the relationship between Fe oxides and HA and As species in the soil is less well understood. In this study, As speciation in an unsaturated soil in the presence of external HA and green synthesized Fe oxide nanoparticles (FeNPs) showed that As(V) was mainly distributed to the specifically-bound (F2), amorphous and poorly-crystalline hydrous oxides of Fe, Al (F3) and the well-crystallized hydrous oxides of Fe and Al (F4). While As(III). This was the major component in unsaturated soil, and was mainly distributed to F4 and the residual fraction (F5). As bound to F3 and F5 was most sensitive to the addition of HA and FeNPs, while HA/FeNPs treatment increased the F3-bound As(V) however, it decreased the F5-bound As(III). Nonetheless the effect of HA on As is completely different to the HA/FeNPs treatment. The increase of As(V) in F3 resulted from F5-bound As(III) oxidation when treated by HA/FeNPs. Cyclic voltammetry confirmed that HA and Fe
Publisher: Wiley
Date: 12-11-2019
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 06-1998
Abstract: The simultaneous determination of amino and organic acids in plant tissue extracts using capillary gas chromatography is described. Plant leaves were extracted in 5% (w/v) perchloric acid and neutralized extracts were purified using C18 cartridges. The amino and organic acids in purified extracts were then converted to tert-butyldimethylsilyl (TBDMS) derivatives prior to separation and detection by capillary gas chromatography (GC) with flame ionization detection. Conditions required for optimal derivatization were investigated. Amino and organic acids were readily converted to their TBDMS derivatives using N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide in dimethylformamide solvent 1:6 (v/v) with an average recovery of 90% and a reproducibility of about 5%. The characteristic [M-57] and [M-159] fragment ion of the TBDMS derivatives was confirmed using GC-MS. The proposed method was demonstrated by the determination of amino and organic acids in extracts of Acacia and Eucalyptus leaves, where detection limits were 1-20 ng.
Publisher: Springer Science and Business Media LLC
Date: 02-2000
DOI: 10.1007/BF02490562
Publisher: Elsevier BV
Date: 15-06-2009
DOI: 10.1016/J.JHAZMAT.2008.10.075
Abstract: The reduction of 2,4,6-trinitrotoluene (TNT) in aqueous solution using nanoscale zero-valent iron (nZVI) was investigated. The results showed that the pseudo-first order reaction law fit the reduction of TNT. The measured apparent rate constant (K(obs)) of TNT on nZVI (0.761 h(-1)) was 7.8-fold than on conventional iron powders (0.0979 h(-1)) at 303 K. The apparent activation energy (E(a)) of nZVI reducing TNT was found to be 24.85 KJ/mol, which was decreased by 60% compared to employing conventional iron powders. The apparent rate constant of TNT reduction on nZVI also can be improved by an increase in nZVI concentration, reaction temperature and a decrease of pH.
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 04-2016
Publisher: Wiley
Date: 07-1997
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.SCITOTENV.2013.07.022
Abstract: Iron nanoparticles were firstly synthesized through a one-step room-temperature biosynthetic route using eucalyptus leaf extracts (EL-Fe NPs). Scanning electron microscopy (SEM) and X-ray energy-dispersive spectrometer (EDS) confirmed the successful synthesis of the spheroidal iron nanoparticles. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared spectrometer (FTIR) indicated that some polyphenols are bound to the surfaces of EL-Fe NPs as a capping/stabilizing agent. Reactivity of EL-Fe NPs was evaluated for the treatment of swine wastewater and results indicated that 71.7% of total N and 84.5% of COD were removed, respectively. This demonstrated the tremendous potential of EL-Fe NPs for in situ remediation of eutrophic wastewater.
Publisher: American Chemical Society (ACS)
Date: 21-07-2020
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 03-2021
Publisher: Springer Science and Business Media LLC
Date: 08-2000
DOI: 10.1007/BF02490444
Publisher: Springer International Publishing
Date: 2014
Publisher: Elsevier BV
Date: 09-2014
Publisher: Wiley
Date: 20-02-2014
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 08-1998
Publisher: MDPI AG
Date: 19-05-2019
DOI: 10.3390/MOLECULES24101926
Abstract: White tea (WT) is one of six tea types originally derived from Fujian Province, China. White tea is known for its health-promoting properties. However, the neuroprotective and anti-aggregatory properties of WT against the hallmark toxic Alzheimer’s protein, Aβ have not been investigated. In this study, WT, green tea (GT), oolong tea (OT) and black tea (BT) were manufactured using tea leaves from the cultivar Camellia sinensis (Jin Guanyin). The protective effects of these tea extracts were then studied under oxidative stress conditions via t-bhp and H2O2 exposure, in addition to Aβ treatment using a PC-12 cell model. Each tea type failed to rescue PC-12 cells from either t-bhp or H2O2-mediated toxicity, however each extract exerted significant protection against Aβ-evoked neurotoxicity. Results of the Thioflavin T Kinetic (ThT) and TEM assay showed that Aβ aggregate formation was inhibited by each tea type. Additionally, TEM also supported the different anti-aggregatory effect of WT by modifying Aβ into an amorphous and punctate aggregate morphology. Higher accumulated precedent or potential neuroprotective compounds in WT, including ECG’’3Me, 8-C-ascorbyl-EGCG, GABA and Gln, in addition to flavonol or flavone glycosides detected by using UPLC-QTOF-MS and UPLC-QqQ-MS, may contribute to a favourable anti-aggregative and neuroprotective effect of WT against Aβ.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.SCITOTENV.2016.04.060
Abstract: This paper reports the detailed composition and morphology of one-step green synthesized bimetallic Fe/Pd nanoparticles (NPs) using grape leaf aqueous extract and identification of active biomolecules involved in the synthesis employing various techniques. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) revealed that Fe/Pd NPs were polydispersed and quasi-spherical with a diameter ranging from 2 to 20nm. X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDS) provided evidence for the composition of Fe and Pd and for their species existing on the surface of Fe/Pd NPs. In addition, biomolecules in the grape leaf aqueous extract were identified but their functions are still unclear. Biomolecules in the aqueous extract such as methoxy-phenyl-oxime, N-benzoyl-2-cyano-histamine, 2-ethyl-phenol, 1,2-benzenediol, β-hydroxyquebracamine, hydroquinone, 2-methoxy-4-vinylphenol, 5-methyl-2-furancarboxaldehyde, 4-(3-hydroxybutyl)-3,5,5-trimethyl-2-cyclohexen and some polyphenolic compounds were identified as reducing and capping agents, which were studied by Chromatography-Mass Spectroscopy (GC-MS), XPS and Fourier Transform Infrared Spectroscopy (FTIR). Our finding suggests a new insight into cost-effective, simple, and environmentally benign production of bimetallic Fe/Pd NPs.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Elsevier BV
Date: 31-10-2007
DOI: 10.1016/J.TALANTA.2007.05.030
Abstract: When inductively coupled plasma mass spectrometry (ICP-MS) is used for the detection of (52)Cr (83.8%) species in ion chromatography (IC), interference from polyatomic ions such as (40)Ar(12)C(+) and (35)Cl(16)O(1)H(+), often occurs due to their mass at m/z 52. To address the issue, an octopole reaction system (ORS) in ICP-MS, including He and H(2) modes, was used to determine whether the background and interference from polyatomic ions could be reduced in the detection of (52)Cr. Compared to standard mode, the polyatomic ions were reduced by either He or H(2) for ex le, more than 97 and 98% of (35)Cl was removed using a He and H(2) tune, respectively. However, the detection sensitivity for (52)Cr was decreased, for ex le, the sensitivity was 27.95 and 67.02% of the standard mode for Cr(EDTA)(2)(-)using a He and H(2) tune, respectively. The H(2) tune is recommended for the detection of (52)Cr at a flow rate of 2.0mL/min with detection limits in the range of 0.2-0.4mug/L. The developed method was used to measure chromium speciation in waters containing high concentration of chloride.
Publisher: Elsevier BV
Date: 30-04-2007
DOI: 10.1016/J.TALANTA.2006.10.041
Abstract: Ion chromatography (IC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was systematically investigated for determining the speciation of chromium in environmental s les. Firstly, the stability of complexes formed by Cr(III) with various aminopolycarboxylic acids was studied by electrospray ionization mass spectrometry (ESI-MS). The results showed that [Cr(EDTA)](-) was stable in solution. Secondly, various mobile phases were examined to separate Cl(-) from chromium species by IC to avoid Cl(-) interference. The separation of [Cr(EDTA)](-) and Cr(VI) was achieved on a new anion-exchange column (G3154A/102) using a mobile phase containing 20mM NH(4)NO(3) and 10mM NH(4)H(2)PO(4) at pH 7.0 without Cl(-) interference. Detection limits for chromium species were below 0.2 microg/L with a direct injection of s le and without prior removal of interferences from the matrix. Finally, the proposed method was used for the determination of chromium species in contaminated waters.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Informa UK Limited
Date: 2000
Publisher: Wiley
Date: 06-02-2014
DOI: 10.1002/CEM.2599
Publisher: Elsevier BV
Date: 02-2020
Publisher: American Chemical Society (ACS)
Date: 08-01-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA10629J
Abstract: The reduction degradation pathway of MB molecules.
Publisher: Elsevier BV
Date: 11-2017
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.AQUATOX.2013.09.005
Abstract: This study investigates the effects of Fe and Fe/Ni nanoparticles on biological denitrification when using Paracoccus sp. strain YF1. Results show that adding Fe and Fe/Ni nanoparticles to the cells decreased their growth and denitrification rate. Compared to that of free cells (control 89.47%), a decrease (64.33%) in the presence of 1000 mg/L Fe/Ni nanoparticles was observed, while a small decline in the denitrification rate (76.36%) was obtained when the concentration of Fe nanoparticles was 1000 mg/L. These were further confirmed by adding Fe(2+), Fe(3+), Fe3O4, Fe(2+)/Ni(2+) and Fe(3+)/Ni(2+) in idually to the free cell system. Furthermore, Fe and Fe/Ni nanoparticles influenced the nitrate removal and bacterial growth under different pH and temperature conditions. SEM, XRD and EDS demonstrated that iron oxides formed as a result of nanoparticles corrosion in biological medium. Finally the presence of nanoparticles around some bacteria was observed.
Publisher: Informa UK Limited
Date: 03-2003
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.CARBPOL.2015.10.002
Abstract: Chitosan-stabilized nanoscale zero-valent iron (CS-nZVI) was prepared and used for the removal of acid fuchsine (AF) from aqueous solution with the assistance of ultrasound. More than 98.9% of AF was removed using CS-nZVI, aged CS-nZVI (exposed to air for 2 months), while only 14.6% removal efficiency was achieved after 15 min by chitosan alone with the assistance of ultrasound. Scanning electron microscopy (SEM) confirmed that chitosan polymers were arranged in a homocentric layered structure. Thus, the polymer can prevent the aggregation of nZVI and increase their anti-oxidation capacity. X-ray diffraction (XRD) also suggested that the chitosan used in synthesis may protect nZVI nanoparticles from air oxidation. Different factors impacting on the removal of AF using CS-nZVI showed that the reduction increased when dosage and temperature increased, but decreased when pH and initial concentration rose. Kinetic studies revealed that the removal of AF fitted well to the pseudo-first-order model. The apparent activation energy was 55.34 kJ/mol, indicating a chemically controlled reaction. Finally, the application of CS-nZVI in dyeing wastewater led to a removal efficiency of 99% of AF, while the reuse test confirmed that AF's removal efficiency declined from 99.6 to 39.3% after seven cycles.
Publisher: Springer Science and Business Media LLC
Date: 20-03-190728634
Publisher: Informa UK Limited
Date: 29-04-2002
Publisher: Elsevier BV
Date: 12-2017
Publisher: American Chemical Society (ACS)
Date: 17-07-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: Springer Science and Business Media LLC
Date: 10-03-2006
DOI: 10.1007/S10653-005-9014-0
Abstract: The concentrations of Cu, Zn, Pb and Cd in soils near a lead-zinc mine located in Shangyu, Zhejiang Province, China, were determined and their toxicity was assessed using the toxicity characteristic leaching procedure (TCLP) developed by the United States Environmental Protection Agency. The TCLP method is a currently recognized international method for evaluation of heavy metal pollution in soils. The available levels of Cu, Zn, Pb and Cd were 8.2-36, 23-143, 6.4-1367 and 0.41-2.2 mg kg(-1), respectively, while the international standards were 15, 25, 5 and 0.5 mg kg(-1), respectively. Soils around the mine were more polluted with Zn and Pb, followed by Cd and Cu. Moreover, the levels of heavy metals in the soils extracted by TCLP indicated that extraction fluid 2 was more effective than extraction fluid 1 in extracting the heavy metals from the polluted soils and there was a positive correlation between fluids 1 and 2. Available heavy metal contents determined by TCLP were correlated with soil total heavy metal contents.
Publisher: Springer Science and Business Media LLC
Date: 06-01-2009
DOI: 10.1007/S10653-008-9225-2
Abstract: There is still no reliable standard extraction method for the speciation of arsenic (As) in plant tissue, and hence there is great interest in developing one for plants that are used as human food. Speciation and bioavailability are critical for accurate human health risk assessment, as As species vary in both their toxicity and bioavailability. Recent incidences of As poisoning in many countries have led to significant research into the fate and dynamics of As in the soil and water environment, including speciation. Although one of the major pathways of ingestion of As is via food, only limited research has been conducted to assess the nature and proportion of various As species present in food crops. In this study, we compared the efficacy of ammonium dihydrogen phosphate and protein extracting solution for the extractability of As from two different species of spinach (amaranth and silverbeet). We found that a microwave-assisted technique with protein extracting solution was most effective, yielding 76-114% extractability and excellent separation and speciation of all As species present in the spinach matrices. The stability test for extracted As species showed them as stable for 45 days without any significant loss or inter-conversion. Both As(III) and As(V) were identified in the shoots of amaranth and silverbeet. However, the percentage of As species varied between amaranth and silverbeet. The silverbeet shoot showed a somewhat higher percentage of As(V), while the amaranth showed a higher percentage of As(III). The s les contained mostly inorganic As, especially As(III) (>90%) in the edible part of the vegetables, a form that is more toxic and bioavailable than other organic and methylated species.
Publisher: Springer Science and Business Media LLC
Date: 08-2010
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.WATRES.2018.09.006
Abstract: The development of new biomaterials for the remove of organic contaminants from wastewater has attracted much attention over the few past years. One of the most cost-effective approaches is to produce new high value biomaterials from low value solid agricultural biowastes. In this work, sugarcane bagasse and agricultural waste rich in reducing sugars, acted as both a green bioreductant for graphene oxide (GO) and a sustainable supporter for the immobilization of Burkholderia cepacia. Therefore, this new biomaterial which contained both reduced graphene oxide (RGO) and Burkholderia cepacia, was cable of initial adsorption of malachite green (MG) and its subsequent biodegradation. After 60 h, immobilized Burkholderia cepacia degraded more MG (98.5%) than a cell cultured Burkholderia cepacia (87.7%) alone. Raman spectroscopy confirmed that GO was successfully reduced by bagasse and that consequently a composite (B-RGO) was prepared. SEM indicated that Burkholderia cepacia was well immobilized and kinetics studies showed that the adsorption of MG onto the developed composite fitted a pseudo-second order kinetics model (R
Publisher: Springer Science and Business Media LLC
Date: 24-02-2010
Publisher: Springer Science and Business Media LLC
Date: 05-2002
DOI: 10.1007/S001280314
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.BIORTECH.2016.03.154
Abstract: This study investigated an integrated and sustainable approach for iron nanoparticles synthesis using Chlorella sp. MM3 biomass produced from the remediation of brewery wastewater. The algal growth characteristics, biomass production, nutrient removal, and nanoparticle synthesis including its characterisation were studied to prove the above approach. The growth curve of Chlorella depicted lag and exponential phase characteristics during the first 4days in a brewery wastewater collected from a single batch of brewing process (single water s le) indicating the growth of algae in brewery wastewater. The pollutants such as total nitrogen, total phosphorus and total organic carbon in single water s le were completely utilised by Chlorella for its growth. The X-ray photoelectron spectroscopy spectra showed peaks at 706.56eV, 727.02eV, 289.84eV and 535.73eV which corresponded to the zero-valent iron, iron oxides, carbon and oxygen respectively, confirming the formation of iron nanoparticle capped with algal biomolecules. Scanning electron microscopy and particle size analysis confirmed the presence of spherical shaped iron nanoparticles of size ranging from 5 to 50nm. To our knowledge, this is the first report on nanoparticle synthesis using the biomass generated from phycoremediation of brewery wastewater.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Springer Science and Business Media LLC
Date: 18-02-2003
DOI: 10.1007/S00216-003-1777-5
Abstract: A simple capillary zone electrophoresis procedure was developed for the separation of arsenic species (AsO(2)(2-), AsO(4)(2-), and dimethylarsinic acid, DMA). Both counter-electroosmotic and co-electroosmotic (EOF) modes were investigated for the separation of arsenic species with direct UV detection at 185 nm using 20 mmol L(-1) sodium phosphate as the electrolyte. The separation selectivity mainly depends on the separation modes and electrolyte pH. Inorganic anions (Cl(-), NO(2)(-), NO(3)(-) and SO(4)(2-)) presented in real s les did not interfere with arsenic speciation in either separation mode. To improve the detection limits, s le-stacking techniques, including large-volume s le stacking (LVSS) and field- lified s le injection (FASI), were investigated for the preconcentration of As species in co-CZE mode. Less than 1 micromol L(-1) of detection limits for As species were achieved using FASI. The proposed method was demonstrated for the separation and detection of As species in water.
Publisher: Elsevier BV
Date: 05-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B705481E
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.ENVPOL.2022.120188
Abstract: Despite arsenic (As) bioavailability being highly correlated with water status and the presence of iron (Fe) minerals, limited information is currently available on how externally applied Fe nanomaterials in soil-rice systems affect As oxidation and stabilization during flooding and draining events. Herein, the stabilization of As in a paddy soil by a phytosynthesized iron oxide nanomaterials (PION) and the related mechanism was investigated using a combination of chemical extraction and functional microbe analysis in soil at both flooding (60 d) and draining (120 d) stages. The application of PION decreased both specifically bound and non-specifically bound As. The As content in rice root, stem, husk and grain was reduced by 78.5, 17.3, 8.4 and 34.4%, respectively, whereas As(III) and As(V) in root declined by 96.9 and 33.3% for the 1% PION treatment after 120 d. Furthermore, the 1% PION treatment decreased the ratio of As(III)/As(V) in the rhizosphere soil, root and stem. Although PION had no significant effect on the overall Shannon index, the distribution of some specific functional microbes changed dramatically. While no As(III) oxidation bacteria were found at 60 d in any treatments, PION treatment increased As(III) oxidation bacteria by 3-9 fold after 120 d cultivation. Structural equation model analysis revealed that the ratio of Fe(III)/Fe(II) affected As stabilization directly at the flooding stage, whereas nitrate reduction and As(III) oxidation microbial groups played a significant role in the stabilization of As at the draining stage. These results highlight that PION exhibits a robust ability to reduce As availability to rice, with chemical oxidation, reduction inhibition and adsorption dominating at the flooding stage, while microbial oxidation, adsorption and coprecipitation dominant during draining.
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 09-2007
DOI: 10.1016/J.ACA.2007.08.012
Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) and electrospray ionization mass spectrometry (ESI-MS) were used as complementary techniques to provide element and molecular information for aminocarboxylic lead species including [Pb(NTA)]1-, [Pb(HEDTA)]1-, [Pb(EDTA)]2- and [Pb(DTPA)]3-. ESI-MS was used to initially confirm the formation of lead aminocarboxylic complexes in solution and subsequently anion-change chromatography coupled with ICP-MS was used to speciate these complexes using a mobile phase containing 30 mM NH4H2PO4 at pH of 8.0. However, [Pb(NTA)]1- was not observed during chromatographic separation due to its poor stability. The species [Pb(HEDTA)]1-, [Pb(EDTA)]2- and [Pb(DTPA)]3- were separated within 15 min with reasonable resolution and detection limits ranging from 0.05 to 0.2 microg L(-1) with simple direct injection of s le. The proposed method was used to speciate aminocarboxylic lead complexes in soil solution.
Publisher: Elsevier BV
Date: 02-2014
Publisher: Elsevier BV
Date: 1999
Abstract: A capillary gas chromatographic (GC) method for the simultaneous determination of organic acids, sugars, and sugar alcohols extracted from plant tissues is described. Plant leaves were extracted in 5% (w/v) perchloric acid and neutralized extracts were purified using C18 cartridges. Organic acids, sugars, and sugar alcohols in purified extracts were converted to their trimethylsilyl (TMS)/TMS-oxime derivatives prior to separation and detection by capillary GC with flame ionization detection (FID). Derivatization procedures were investigated in detail and the compounds of interest were readily converted to their TMS/TMS-oxime derivatives using hexamethyldisiazane reagent in acetonitrile solvent (1:6 v/v) at 100 degreesC for 60 min. The derivatives were sufficiently volatile and stable. The FID response to derivatized compounds was generally linear in the concentration range 30-300 microg ml-1, with detection limits in the order of 3-76 ng. The proposed method was demonstrated for the determination of organic acids, sugars, and sugar alcohols in leaf extracts of two native Australian plants.
Publisher: Informa UK Limited
Date: 13-07-2010
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.JCIS.2011.10.080
Abstract: The {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films are prepared by LBL electrostatic assembly technique, and their uniform and homogeneous traits have been verified by cyclic voltammetry. The {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films with PAMAM as the outmost layer, having an open structure and exhibiting good penetrability for the solvent molecules at low pH, are used as matrices for electro-deposition of Pt micro-nano clusters in situ. X-ray photoelectron spectroscopy (XPS) analysis and field emission scanning electron microscope (FE-SEM) characterization show that the unique Pt micro-nano clusters with flower-like structure have been immobilized on the surface of {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films. The morphologies of Pt micro-nano clusters are influenced by electro-deposition conditions such as deposition potential, deposition time, and the number of layers of {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films. Pt(-clusters)-{PMo(12)/PAMAM}(3) composite films demonstrate good electrocatalytic activities regarding methanol oxidation and improved tolerance of CO.
Publisher: Elsevier BV
Date: 04-1997
Publisher: Royal Society of Chemistry (RSC)
Date: 1998
DOI: 10.1039/A801244J
Publisher: Informa UK Limited
Date: 09-1998
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 03-2004
DOI: 10.1016/J.CHROMA.2003.12.011
Abstract: Co(II), Zn(II), Ni(II) and Fe(I) were successfully separated by capillary electrophoresis using pre-capillary and on-capillary complexation with 4-(2-thiazolylazo)resorcinol. The influences of some crucial parameters, including both pre- and on-capillary complexation procedure, were investigated. For on-capillary complexation, the complexing reaction was carried out inside the capillary by mixing the zones of ligand and s le during the electrophoretic migration. Compared with pre-capillary complexation, the method provided 30-fold reduction in detection limits for Co(II), 50-fold reduction for Zn(II), and 100-fold reduction for Ni(II) and Fe(II). It was used for the analysis of a pharmaceutical and tap water s le.
Publisher: Springer Science and Business Media LLC
Date: 12-2007
Publisher: Elsevier BV
Date: 10-1999
DOI: 10.1016/S0021-9673(99)00885-7
Abstract: 2,6-Pyridinedicarboxylic acid (PDCA) was evaluated as an eluent for indirect UV and non-suppressed conductivity detection of carboxylic acids in ion-exclusion chromatography. The effect of PDCA concentration on the separation and detection sensitivity was investigated. The reasonable resolutions between carboxylic acids were achieved using 1 mM PDCA eluent. Detection limits were 1.0-7.0 microM for conductivity detection and 8-30 microM for UV detection. Compared to the eluent containing 1 mM sulfuric acid, the method offers a high resolution and high detection sensitivity for both detectors due to its high molar absorptivity and low background conductance. The proposed method was demonstrated to be useful for the determination of carboxylic acids in environmental s les with direct s le injection.
Publisher: Informa UK Limited
Date: 19-08-2002
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.SCITOTENV.2018.12.225
Abstract: This study of Cu(II)'s impact on aerobic denitrification of Paracoccus sp. YF1 revealed that the denitrification rate decreased markedly from 99.8%, 98.0%, 68.7% to 16.3% when the concentrations of Cu(II) rose from 0, 0.01 mM, 0.05 mM to 0.1 mM, respectively. This outcome was confirmed by the successful test of OD
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.JHAZMAT.2021.127185
Abstract: The widespread presence of 17β-estradiol (E2) in the environment is an emerging problem because it poses a potential threat to human health and aquatic organisms. In this study, a strain of E2 degrading bacteria was isolated from activated sludge. 16s rRNA analysis combined with physiological and biochemical detection confirmed that the bacterium was Ochrobactrum sp. strain FJ1. At an initial E2 concentration of 15 mg L
Publisher: Elsevier BV
Date: 04-2023
Publisher: Springer Science and Business Media LLC
Date: 19-05-2015
DOI: 10.1038/NCOMMS7760
Abstract: Brain iron elevation is implicated in Alzheimer’s disease (AD) pathogenesis, but the impact of iron on disease outcomes has not been previously explored in a longitudinal study. Ferritin is the major iron storage protein of the body by using cerebrospinal fluid (CSF) levels of ferritin as an index, we explored whether brain iron status impacts longitudinal outcomes in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort. We show that baseline CSF ferritin levels were negatively associated with cognitive performance over 7 years in 91 cognitively normal, 144 mild cognitive impairment (MCI) and 67 AD subjects, and predicted MCI conversion to AD. Ferritin was strongly associated with CSF apolipoprotein E levels and was elevated by the Alzheimer’s risk allele, APOE-ɛ4 . These findings reveal that elevated brain iron adversely impacts on AD progression, and introduce brain iron elevation as a possible mechanism for APOE-ɛ4 being the major genetic risk factor for AD.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 08-2021
DOI: 10.1016/J.SCITOTENV.2022.155704
Abstract: Antimony (Sb) contamination is a significant environmental issue in mining impacted areas, where the use of nanomaterials to remove such metalloid species has attracted much research attention. In this study, the simultaneous removal of Sb(III) and Sb(V) was investigated using a reduced graphene oxide/Fe/Ni (rGO-Fe/Ni NPs) composite. Compared to rGO alone the composite exhibited enhanced removal efficiency. For rGO-Fe/Ni NPs the maximum Sb(III) and Sb(V) adsorption capacities were 2.00 and 1.41 mg·g
Publisher: Wiley
Date: 09-1999
DOI: 10.1002/(SICI)1521-4109(199909)11:13<964::AID-ELAN964>3.0.CO;2-3
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.JHAZMAT.2019.120811
Abstract: The application of green synthesized iron nanoparticles (nFe) for the removal of arsenic (As) from contaminated sites has often been proposed as one of the most promising remediation methods. In this work, TEM analysis showed that As(V) was uniformly adsorbed on the surfaces of nFe, while FTIR analysis confirmed that adsorption was mainly via an FeOAs bond, and XPS analysis indicated that only As(V) was adsorbed. Hence, the removal mechanism proposed for As(V) is based on initially nFe reacting with As(V) to form a monodentate chelating ligand and subsequently a bidentate binuclear complex. The initially high surface area (51.14 m
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.ENVPOL.2019.01.108
Abstract: Antibiotics in water and soil are persistent, bioaccumulative and toxic to aquatic organisms and human health. To address it, as one of the new technologies, green synthesized magnetic Fe
Publisher: Elsevier BV
Date: 07-2021
Publisher: Springer Science and Business Media LLC
Date: 10-2001
DOI: 10.1007/BF02491206
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.JCIS.2013.08.020
Abstract: Iron nanoparticles (Fe NPs) were synthesized using tea extracts as a catalyst for the Fenton-like oxidation of monochlorobenzene (MCB), where 69%, 53%, and 39% of MCB were, respectively, degraded by Fe NPs synthesized using green tea extracts, oolong tea extracts, and black tea extracts. Fe NPs synthesized using green tea extracts (GT-Fe NPs) demonstrated the best degradation since green tea contains a high concentration of caffeine olyphenols used as both reducing and capping agents in the synthesis of Fe NPs. This was confirmed by SEM image, EDS, and XRD pattern of GT-Fe NPs. In addition, batch experiments show that the oxidation of MCB and the removal of chemical oxygen demand (COD) using GT-Fe NPs were 81% and 31%, respectively, at optimal conditions, where dosages were 0.6g/L GT-Fe NPs, 0.045 mol/L H2O2, and initial pH of 3.0. Compared to homogeneous Fenton oxidation of MCB, GT-Fe NPs as a heterogeneous catalyst indicate that Fe(2+) and Fe(3+) leached from GT-Fe NPs nanoparticles and consequently reduced the formation of iron sludge. Finally, GT-Fe NPs were successful in removing MCB from wastewaters, and the possible Fenton-like oxidative mechanism of MCB was proposed. The proposition was based on adsorption of MCB on the surface of GT-Fe NPs, decomposition of H2O2, generation of hydroxyl radicals, and oxidation of MCB.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.SAA.2014.04.037
Abstract: Iron nanoparticles (Fe NPs) are often synthesized using sodium borohydride with aggregation, which is a high cost process and environmentally toxic. To address these issues, Fe NPs were synthesized using green methods based on tea extracts, including green, oolong and black teas. The best method for degrading malachite green (MG) was Fe NPs synthesized by green tea extracts because it contains a high concentration of caffeine olyphenols which act as both reducing and capping agents in the synthesis of Fe NPs. These characteristics were confirmed by a scanning electron microscope (SEM), UV-visible (UV-vis) and specific surface area (BET). To understand the formation of Fe NPs using various tea extracts, the synthesized Fe NPs were characterized by SEM, X-ray energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD). What emerged were different sizes and concentrations of Fe NPs being synthesized by tea extracts, leading to various degradations of MG. Furthermore, kinetics for the degradation of MG using these Fe NPs fitted well to the pseudo first-order reaction kinetics model with more than 20 kJ/mol activation energy, suggesting a chemically diffusion-controlled reaction. The degradation mechanism using these Fe NPs included adsorption of MG to Fe NPs, oxidation of iron, and cleaving the bond that was connected to the benzene ring.
Publisher: Springer Science and Business Media LLC
Date: 09-02-2016
DOI: 10.1007/S11356-016-6193-4
Abstract: In this study, the influence of soil types on the effect of the commercial form of C-nZVI on tissue concentrations, cellular component, reproduction outcome in Eisenia fetida, and the soil health was investigated. C-nZVI at concentration level of 3 g kg(-1) soil showed no effect on the survival of E. fetida in the three soil types. However, varying effects such as concentration-dependent increase in tissue iron concentration, lipid peroxidation, and damage to DNA molecules by C-nZVI were observed. C-nZVI at an exposure concentration of 60 mg kg(-1) soil induced oxidative stress in E. fetida. Tissue Fe concentration appeared correlated to the DNA damage. Oxidative stress and DNA damage may explain the toxicity mechanisms of nZVI to E. fetida. Graphical Abstract Reactive oxygen species induced by nZVI.
Publisher: Elsevier BV
Date: 06-2007
Publisher: Wiley
Date: 11-2006
Abstract: A method based on ion chromatography (IC) and inductively coupled plasma MS (ICP-MS) was developed for the speciation of arsenic in water and soil extracts. An anion-exchange column (G3154A/101) was used to separate As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) with excellent resolution. Various ammonium salts, including NH4H2PO4, (NH4)2HPO4, (NH4)2CO3, and NH4HCO3, were examined as eluents to reduce matrix interference from chloride and to solve clogging problems. The best arsenic speciation was obtained within 9 min with excellent resolution and without interference from high chloride concentrations using an eluent containing 7.5 mM (NH4)2HPO4 at pH 7.9. The detection limits for the target arsenic species ranged from 0.1 to 0.4 microg/L with direct injection of s le without matrix elimination. The proposed method was effectively demonstrated by determining arsenic species in contaminated waters and soils of Bangladesh.
Publisher: Elsevier BV
Date: 05-2013
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 08-2013
Publisher: Springer Science and Business Media LLC
Date: 07-09-2014
DOI: 10.1007/S11356-013-2099-6
Abstract: This study investigated kaolin-supported nanoscale zero-valent iron (nZVI/K) as a heterogeneous Fenton-like catalyst for the adsorption and oxidation of an azo dye, Direct Black G (DBG). New findings suggest that kaolin as a support material not only reduced the aggregation of nanoscale zero-valent iron (nZVI) but also improved the adsorption of DBG. It consequently improved Fenton oxidation by increasing the local concentration of DBG in the vicinity of nZVI. This was confirmed by scanning electron microscopy and X-ray diffraction for the surface morphology of nZVI/K before and after the Fenton-like reaction. Furthermore, nZVI/K proved to be a catalyst for the heterogeneous Fenton-like oxidation of the DBG process in the neutral pH range. More than 87.22 % of DBG was degraded, and 54.60 % of total organic carbon was removed in the optimal conditions: 0.6 g/L dosage of nZVI/K, 33 mM H2O2, 100 mg/L initial DBG concentration, temperature of 303 K and pH of 7.06. Finally, it was demonstrated that nZVI/K removed DBG from dye wastewater through the processes of adsorption and oxidation.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 04-1999
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 05-2013
Publisher: Springer Science and Business Media LLC
Date: 11-2013
DOI: 10.1007/S11356-012-1272-7
Abstract: Clays such as kaolin, bentonite and zeolite were evaluated as support material for nanoscale zero-valent iron (nZVI) to simultaneously remove Cu(2+) and Zn(2+) from aqueous solution. Of the three supported nZVIs, bentonite-supported nZVI (B-nZVI) was most effective in the simultaneous removal of Cu(2+) and Zn(2+) from a aqueous solution containing a 100 mg/l of Cu(2+) and Zn(2+), where 92.9 % Cu(2+) and 58.3 % Zn(2+) were removed. Scanning electronic microscope (SEM) revealed that the aggregation of nZVI decreased as the proportion of bentonite increased due to the good dispersion of nZVI, while energy dispersive spectroscopy (EDS) demonstrated the deposition of copper and zinc on B-nZVI after B-nZVI reacted with Cu(2+) and Zn(2+). A kinetics study indicated that removing Cu(2+) and Zn(2+) with B-nZVI accorded with the pseudo first-order model. These suggest that simultaneous adsorption of Cu(2+)and Zn(2+) on bentonite and the degradation of Cu(2+)and Zn(2+) by nZVI on the bentonite. However, Cu(2+) removal by B-nZVI was reduced rather than adsorption, while Zn(2+) removal was main adsorption. Finally, Cu(2+), Zn(2+), Ni(2+), Pb(2+) and total Cr from various wastewaters were removed by B-nZVI, and reusability of B-nZVI with different treatment was tested, which demonstrates that B-nZVI is a potential material for the removal of heavy metals from wastewaters.
Publisher: Elsevier BV
Date: 10-2017
Publisher: Wiley
Date: 02-1997
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.JHAZMAT.2010.08.122
Abstract: In this study, organobentonites were prepared by modification of bentonite with various cationic surfactants, and were used to remove As(V) and As(III) from aqueous solution. The results showed that the adsorption capacities of bentonite modified with octadecyl benzyl dimethyl ammonium (SMB3) were 0.288 mg/g for As(V) and 0.102 mg/g for As(III), which were much higher compared to 0.043 and 0.036 mg/g of un-modified bentonite (UB). The adsorption kinetics were fitted well with the pseudo-second-order model with rate constants of 46.7 × 10(-3)g/mgh for As(V) and 3.1 × 10(-3)g/mgh for As(III), respectively. The maximum adsorption capacity of As(V) derived from the Langmuir equation reached as high as 1.48 mg/g, while the maximum adsorption capacity of As(III) was 0.82 mg/g. The adsorption of As(V) and As(III) was strongly dependent on solution pH. Addition of anions did not impact on As(III) adsorption, while they clearly suppressed adsorption of As(V). In addition, this study also showed that desorbed rates were 74.61% for As(V) and 30.32% for As(III), respectively, after regeneration of SMB3 in 0.1M HCl solution. Furthermore, in order to interpret the proposed absorption mechanism, both SMB3 and UB were extensively characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Oxford University Press (OUP)
Date: 04-2022
DOI: 10.1093/JTM/TAAC055
Abstract: In this manuscript, we critically assess the evidence around various methods of reducing mobility, and how these have impacted the course of the coronavirus disease 2019 (COVID-19) pandemic. We further highlight the difficulty in assessing the effectiveness of such measures before giving directions for future research.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.CHEMOSPHERE.2022.135936
Abstract: Since ofloxacin (OFX) is one of many common antibiotics, which effluxes into aquatic environment in relatively high concentration, it has become of significant environmental concern due to the potential for increased antibiotic resistance. In this study, an innovative functional Fe/Ni@ZIF-8 composite was successfully used for the Fenton-like oxidation of OFX, with a OFX removal efficiency >98% under optimal conditions. FTIR analysis confirmed that OFX removal occurred via adsorption to Fe/Ni@ZIF-8 by a combination of π-π bond intercalation and electrostatic interaction, while XPS revealed that the Fe/Ni NPs in Fe/Ni@ZIF-8 were also involved in oxidation. Furthermore, LC-MS analysis identified the presence of several OFX degradation products post exposure, which indicted that Fe/Ni NPs in Fe/Ni@ZIF-8 reacted with H
Publisher: Elsevier BV
Date: 09-1997
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.WATRES.2011.04.010
Abstract: The use of nanoscale zero-valent iron (nZVI) to remediate contaminated groundwater is limited due to its lack of durability and mechanical strength. To address this issue, 20% (w/w) nZVI was loaded onto kaolinite as a support material (K-nZVI). More than 96% of Pb(2+) was removed from aqueous solution using K-nZVI at an initial condition of 500 mg/L Pb(2+) within 30 min under the conditions of 10 g/L of K-nZVI, pH 5.10 and a temperature of 30 °C. To understand the mechanism of removal of Pb(2+), various techniques were implemented to characterize K-nZVI. Scanning electron microscopy (SEM) indicated that K-nZVI had a suitable dispersive state with a lower aggregation, where the mean specific surface area and average particle size as determined by the BET-N(2) method and X-ray diffraction (XRD), were 26.11 m(2)/g and 44.3 nm, respectively. The results obtained from XRD, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) indicated that a small number of iron oxides formed on the surface of K-nZVI, suggesting that free Pb(2+) was adsorbed onto K-nZVI and subsequently reduced to Pb(0).
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 06-2008
Publisher: Wiley
Date: 06-01-2009
DOI: 10.1002/RCM.3897
Abstract: The speciation of Zn-aminopolycarboxylic complexes was investigated using both electrospray ionization mass spectrometry (ESI-MS) and ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP-MS). The resulting ESI mass spectra indicated that [Zn(HEDTA)](1-), [Zn(NTA)](1-), [Zn(EDTA)](2-) and [Zn(DTPA)](3-) were all simultaneously detected in solution [Zn(NTA)](1-) exhibited the weakest intensity of all these Zn-aminopolycarboxylic complexes. IC/ICP-MS was also successfully used to separate Zn complexes by anion-exchange chromatography using a mobile phase containing 30 mM (NH(4))(2)HPO(4) at pH 7.5 giving reasonable resolution within 15 min. A weak peak attributable to the poor stability [Zn(NTA)](1-) ion was also observed using IC/ICP-MS. With the exception of [Zn(NTA)](1-), detection limits ranging from 0.5 to 1.0 microg/L were obtained and the proposed method was used for the determination of Zn aminopolycarboxylic complexes in soil solution.
Publisher: Elsevier BV
Date: 05-2016
Publisher: Wiley
Date: 09-2000
Publisher: Elsevier BV
Date: 05-2023
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.CHEMOSPHERE.2018.04.162
Abstract: In this paper, iron-based nanoparticles (Fe NPs) synthesized by Euphorbia cochinchensis leaf extract were used to remove 2,4-dichlorophenol (2,4-DCP). The possible mechanism for removing the adsorption and heterogeneous Fenton-like oxidation of 2,4-DCP was investigated. Various parameters affecting removal efficiency were tested, and the results showed that more than 83.5% of 2,4-DCP was removed with the addition of 10 mM H
Publisher: Elsevier BV
Date: 05-1995
Publisher: Springer Science and Business Media LLC
Date: 07-2002
DOI: 10.1007/BF02490254
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.JHAZMAT.2019.120832
Abstract: Despite numerous studies having been conducted on the stabilization of heavy metal contaminated soil, our understanding of the mechanisms involved remains limited. Here green synthesized iron oxide nanoparticles (GION) were applied to stabilize cadmium (Cd) in a contaminated soil. GION not only stabilized soil Cd, but also improved soil properties within one year of incubation. After GION application both the exchangeable and carbonate bound Cd fractions decreased by 14.2-83.5% and 18.3-85.8% respectively, and most of the Cd was translocated to the residual Cd fraction. The application of GION also strongly altered soil bacterial communities. In GION treatments, the abundance of Gemmatimonadetes, Proteobacteria, and Saccharibacteria increased which led to a shift in the dominant bacterial genera from Bacillus to Candidatus koribacter. The variation in bacteria confirmed the restoration of the contaminated soil. The most abundant bacterial genus and species found in GION treatments were related to (i) plant derived biomass decomposition (ii) ammoxidation and denitrification and (iii) Fe oxidation. GION application may enhance the formation of larger soil aggregates with anaerobic centers and coprecipitation coupled Fe (II) oxidization, ammoxidation and nitrite reduction followed by Fe mineral ripening may be involved in Cd stabilization. The predominant stabilization mechanism was thus coprecipitation-ripening-stabilization.
Publisher: Springer Science and Business Media LLC
Date: 05-02-2009
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.CHEMOSPHERE.2022.135269
Abstract: Arsenic contamination is an increasing global environmental problem, especially in mining industry wastewater where both arsenite (As(III)) and arsenate (As(V)) have been routinely detected. In this paper, a novel porous metal-organic framework material (ZIF-8) was composited with iron nanoparticles (FeNPs) to form a functional material (ZIF-8@FeNPs) for the simultaneous removal of As(III)/(V) from wastewater. The material effectively removed both As(III) and As(V) with removal efficiencies of 99.9 and 71.2%, respectively. Advanced characterization techniques including X-ray photoelectron spectroscopy (XPS) and Fourier infrared (FTIR) indicated that removal of As(III) and As(V) involved complex formation. Adsorption kinetics followed a pseudo-second order kinetics indicating adsorption involved chemisorption. After four cycles of reuse the he removal rate of As species was still relatively high at > 60% When ZIF-8@FeNPs were used to remove As from real wastewater from acid mines the removal efficiency was 94.27%. Finally, a As(III) and As(V) removal mechanism was proposed.
Publisher: Elsevier BV
Date: 07-1999
DOI: 10.1016/S0039-9140(99)00070-3
Abstract: A graphite carbon electrode was used for the potentiometric detection of ascorbate. The electrode exhibits a linear response with a slope of -42+/-1.0 mV decade(-1) in concentrations ranging from 5x10(-4) to 5.0x10(-2) M in 0.1 M NaOH solution with a detection limit of 5.0x10(-6) M. The response mechanism of this electrode was investigated by potentiometry, voltammetry, and scanning electron micoscropy (SEM), and it suggests that the electrode potential change resulted from the ion-exchange adsorption and subsequent oxidation of ascorbate on the electrode surface at pH 12-13. The electrode exhibits high sensitivity, selectivity and reproducibility.
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CHEMOSPHERE.2018.05.199
Abstract: Reduction of graphene oxide (RGO) utilizing green methods such as plants has attracted much attention due to its efficiency, eco-friendly features and low cost. However, the key components in plant extracts and their bioreduction functions concerning GO are still not well understood. In this study, the GO was reduced by Eucalyptus leaf (EL) extract. The optimal conditions for bioreduction were at volume ratio of leaf extract (10 g L
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.JHAZMAT.2013.09.028
Abstract: Bentonite supported Fe/Pd nanoparticles (B/nZVI/Pd) were synthesized as composites that exhibit functionalities assisting in the removal of methyl orange (MO) from aqueous solution. The results showed that 91.87% of MO was removed using B/nZVI/Pd, while only 85% and 1.41% of MO were removed using nZVI/Pd and bentonite after 10 min, respectively. The new findings include that the presence of bentonite decreased the aggregation of nZVI/Pd and nZVI in the composite played its role as a reductant, while Pd(0) acted as the catalyst to enhance the degradation of MO, which were confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis analysis and the batch experiments. The increase in B/nZVI/Pd loading led to greater removal efficiency, while decolorization efficiency declined in the presence of anions such as nitrate, sulfite and carbonate, especially nitrate, which decreased the apparent rate constant k(obs) almost 17.06-fold. The kinetics study indicated that the degradation of MO fitted well to the pseudo-first-order model, where the k(obs) was 0.0721 min(-1). Finally, the reactivity of aged B/nZVI/Pd was investigated, and the application of B/nZVI/Pd in wastewater indicated a removal efficiency higher than 93.75%. This provided a new environmental pollution management option for dyes-contaminated sites.
Publisher: Elsevier BV
Date: 10-1999
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.JENVMAN.2022.115526
Abstract: The integration of metal-organic frameworks with other functional materials has recently emerged as a promising approach for creating innovative materials for environmental remediation. Here, a nano-sized iron/nickel (Fe/Ni) functionalized zeolitic imidazolate framework-8 (ZIF-8-Fe/Ni) was fabricated for oxytetracycline (OTC) removal from wastewater. Cyclic voltammetry and erometric I-t measurements indicated that OTC was degraded by ZIF-8-Fe/Ni. X-ray diffraction spectroscopy (XRD), transmission electron microscopy mapping (TEM-mapping) and X-ray photoelectron spectroscopy (XPS) indicated that Fe/Ni was evenly dispersed throughout ZIF-8 and partially oxidized after reaction with OTC. OTC adsorption isotherms and kinetics best fitted the Langmuir isotherm (R
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 08-2000
Publisher: Informa UK Limited
Date: 09-2003
Publisher: Oxford University Press (OUP)
Date: 09-05-2017
Abstract: Assessment of total petroleum hydrocarbons (TPHs) from contaminated sites demands routine and reliable measurement at trace levels. However, the detection limits of these methods need to be improved. This study developed the programmable temperature vaporization-large volume injection (PTV-LVI) method to quantify TPHs through gas chromatography-flame ionization detection. This configuration enhances the method sensitivity for trace level detections through large volume injections and pre-concentration of analytes along the injection liner. The method was evaluated for the three commonly observed hydrocarbon fractions: C10-C14, C15-C28 and C29-C36. In comparison with conventional injection methods (splitless and pulsed splitless), PTV-LVI showed R2 values > 0.999 with enhanced limits of detection and limits of quantification values. The method was applied to real s les for routine environmental monitoring of TPHs in an Australian contaminated site characterized by refueling station. Analysis of groundwater s les in the area showed a wide range of TPH concentrations as follows: 66-1,546,000 (C10-C14), 216-22,762 (C15-C28) and 105-2,103 (C29-C36) μg/L. This method has detected trace levels, thereby measuring a wider concentration range of TPHs. These more accurate measurements can lead to the appropriate application of risk assessments and remediation techniques.
Publisher: Springer Science and Business Media LLC
Date: 16-12-2009
DOI: 10.1007/S10653-008-9227-0
Abstract: We have developed a novel microwave-assisted extraction method for determining the arsenic (As) speciation in soils that is based on extraction with phosphate solutions, including orthophosphoric acid, ammonium dihydrogen orthophosphate, and ammonium hydrogen orthophosphate. The highest extracting efficiency was obtained with 1 M ortho-phosphoric acid solution as the extractant, and this efficiency is associated with the pH of the extractant. Total As content and As species in the soil extracts were determined by inductively coupled plasma mass spectrometry (ICP-MS) alone and by the combined ion chromatography (IC) with ICP-MS, respectively. The proposed extraction procedure was applied to National Institute of Standards and Technology (NIST) standard reference material (SRM) 2711 (Montana soil) as well as to environmental soil s les collected from the agricultural lands of Bangladesh. As(V) was detected in all the soil s les, and As(III) was detected in nine soils of the 20. These results of extractable As testing indicate that the extraction of As species mainly depends on the composition of the soils. The As speciation results also indicate that As adsorption is highly dependent on the iron, aluminum, and manganese concentrations in the soil. The stability of As species in the extracts was also studied.
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 2011
Publisher: Springer Science and Business Media LLC
Date: 23-09-2014
Publisher: Elsevier BV
Date: 08-2002
DOI: 10.1016/S0021-9673(02)00741-0
Abstract: On-column complexation of metal ions with 2,6-pyridinedicarboxylate (2,6-PDC) to form anionic complexes enabled their separation by capillary zone electrophoresis with direct UV detection at 214 nm. Nine metal ions, Cu2+, Zn2+, Ni2+, Cd2+ Mn2+, Pb2+, Fe3+, Al3+ and Ca2+, were determined in less than 7 min using 10 mM 2.6-PDC solution containing 0.75 mM tetradecyltrimethylammonium bromide at pH 4.0. Satisfactory working ranges (20-300 microM), detection limits (3-10 microM) and good repeatability of the peak areas (RSD 2.1-4.2%, n=5) were obtained using hydrodynamic injection (30 s). The proposed method was used successfully for the determination of Mn2+, Fe3+, Al3+ and Ca2+ in groundwaters.
Publisher: Elsevier BV
Date: 2008
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/SH07068
Abstract: Background: Although Neisseria gonorrhoeae (Ng) and Chlamydia trachomatis (Ct) are common infections in men who have sex with men, it is unclear from previous studies whether anorectal symptoms are reliable clinical indicators of infection. Aim: The objective of the study was to investigate the clinical significance of questionnaire-elicited or clinically reported anal symptoms for rectal Ng and Ct. Methods: During 2002 to 2003, men who have sex with men (MSM) screened or tested for Ng or Ct according to the national guidelines were invited to participate in a questionnaire. Results: During the study period, 366 MSM were enrolled into the study (88% recruitment rate), of whom 20 (5%) and 25 (7%) were diagnosed with rectal Ng or Ct, respectively. Overall, ‘any’ anorectal symptoms on a questionnaire were reported equally by those with and without rectal Ng (75 v. 74%, P = 0.69), but heavy anal discharge (P 0.01) and anal pain (P = 0.04) were more common in those with rectal Ng. Symptoms on the questionnaire were not different among those with and without Ct. Any anal symptoms were reported substantially more often via questionnaire than in a clinical consultation (75 v. 16%, P 0.01) and symptoms reported in a clinical consultation were not associated with Ng or Ct detection. Conclusion: The weak or absent association between symptoms and the presence of Ct or Ng highlights the importance of annual sexually transmitted infection screening in MSM regardless of symptoms.
Publisher: Elsevier BV
Date: 31-07-2007
DOI: 10.1016/J.TALANTA.2007.02.014
Abstract: A non-suppressed ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for simultaneous determination of trace iodate and iodide in seawater. An anion-exchange column (G3154A/101, provided by Agilent) was used for the separation of iodate and iodide with an eluent containing 20mM NH(4)NO(3) at pH 5.6, which reduced the build-up of salts on the s ler and skimmer cones. The influences of competing ion (NO(3)(-)) in the eluent on the retention time and detection sensitivity were investigated to give reasonable resolution and detection limits. Linear plots were obtained in a concentration range of 5.0-500 microg/L and the detection limit was 1.5 microg/L for iodate and 2.0 microg/L for iodide. The proposed method was used to determinate iodate and iodide in seawaters without s le pre-treatment with exception of dilution.
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.SCITOTENV.2018.01.170
Abstract: To effectively reuse adsorbent in removal of Cd (II), magnetic modification was considered as an alternative. In this study, iron oxide nanoparticles (IONPs) synthesized from the extract of Excoecaria cochinchinensis Lour leaves were modified by low-temperature calcination, and used to remove Cd (II). Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and magnetic properties analysis confirmed the successful synthesis of nanoscale magnetic FeOC composite. Response surface methodology (RSM) served to optimize the adsorption of Cd (II) by IONPs based on Box-Behnken design (BBD). According to the quadratic model, the effect of each factor on the removal of Cd (II) by IONPs was: pH > dosage > ionic strength > temperature. In percentage terms, 98.50% of Cd (II) (10 mg L
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.ECOENV.2014.03.028
Abstract: Burkholderia vietnamiensis C09V (B.V. C09V) was used to remove both crystal violet (CV) and Cu(II) because dye effluents often contain dyes and metal ions. Inhibiting the strain׳s growth through the biosorption of Cu(II) on B.V. C09V and promoting its growth by using CV as a carbon source led to the degradation of CV (30mg/L). It fell to 36.9 percent and the amount of Cu(II) (50mg/L) removed rose to 34.9 percent in the presence of both CV and Cu(II). This outcome is comparable to the single presence of CV and Cu(II). EDS analysis showed that Cu(II) was adsorbed onto the strain (the atomic percentage of Cu(II) was 1.9 percent), while kinetic studies indicated that firstly, the decolorization of CV fitted well to the pseudo first-order degradation kinetic model and secondly, the biosorption of Cu(II) fitted well to the pseudo second-order kinetic model. The degradation rate constants of CV were stable in the 0.101-0.0068/h range and R(2) was both higher than 0.981 when Cu(II) concentrations were present. Furthermore, the biosorption capacity of Cu(II) ranged from 38.8 to 20.3mg/g at the CV concentration of 30mg/L (both R(2)>0.96). This suggests that the strain has the potential to degrade CV and facilitate the biosorption of Cu(II) in dye effluent.
Publisher: Informa UK Limited
Date: 10-1997
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA13337A
Abstract: A new functional biomaterial based on Burkholderia vietnamiensis C09V (C09V) was immobilized on beads and used for simultaneous removal of both heavy metals and crystal violet (CV).
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.JHAZMAT.2015.10.034
Abstract: To reduce cost and enhance reactivity, bimetallic Fe/Pd nanoparticles (NPs) were firstly synthesized using grape leaf aqueous extract to remove Orange II. Green synthesized bimetallic Fe/Pd NPs (98.0%) demonstrated a far higher ability to remove Orange II in 12h compared to Fe NPs (16.0%). Meanwhile, all precursors, e.g., grape leaf extract, Fe(2+) and Pd(2+), had no obvious effect on removing Orange II since less than 2.0% was removed. Kinetics study revealed that the removal rate fitted well to the pseudo-first-order reduction and pseudo-second-order adsorption model, meaning that removing Orange II via Fe/Pd NPs involved both adsorption and catalytic reduction. The remarkable stability of Fe/Pd NPs showed the potential application for removing azo dyes. Furthermore, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the changes in Fe/Pd NPs before and after reaction with Orange II. High Performance Liquid Chromatography-Mass Spectrum (HPLC-MS) identified the degraded products in the removal of Orange II, and finally a removal mechanism was proposed. This one-step strategy using grape leaf aqueous extract to synthesize Fe/Pd NPs is simple, cost-effective and environmentally benign, making possible the large-scale production of Fe/Pd NPs for field remediation.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Springer Science and Business Media LLC
Date: 28-05-2014
DOI: 10.1007/S11356-014-3037-Y
Abstract: A new strain isolated from activated sludge and identified as Burkholderia vietnamiensis C09V was used to biodegrade crystal violet (CV) from aqueous solution. To understand the degradation pathways of CV, batch experiments showed that the degradation using B. vietnamiensis C09V significantly depended on conditions such as pH, initial dye concentration and media components, carbon and nitrogen sources. Acceleration in the biodegradation of CV was observed in presence of metal ions such as Cd and Mn. More than 98.86C of CV (30 mg l(-1)) was degraded within 42 h at pH 5 and 30 °C. The biodegradation kinetics of CV corresponded to the pseudo first-order rate model with a rate constant of 0.046 h(-1). UV-visible and Fourier transform infrared spectroscopy (FTIR) were used to identify degradation metabolites. Which further confirmed by LC-MS analysis, indicating that CV was biodegraded to N,N-dimethylaminophenol and Michler's ketone prior to these intermediates being further degraded. Finally, the ability of B. vietnamiensis C09V to remove CV in wastewater was demonstrated.
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.CHEMOSPHERE.2017.06.038
Abstract: Kaolin supported nanoscale zero-valent iron (K-nZVI) is synthesized and applied as the Fenton-like oxidation catalyst to degrade a model azo dye, Direct Black G (DBG). The characterization of K-nZVI by the high resolution transmission electronmicroscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Energy Diffraction Spectrum (EDS) and X-ray diffraction (XRD) show that kaolin as a support material not only reduces the aggregation of zero-valent iron (nZVI) but also facilitates the Fenton-like oxidation by increasing the local concentration of DBG in the vicinity of nZVI. Pseudo first-order and pseudo second-order kinetic models are employed to reveal the adsorption and degradation of the DBG using K-nZVI as the catalyst. A better fit with pseudo second-order model for the adsorption process and equal excellent fits with pseudo first-order and pseudo second-order models for the degradation process are observed the adsorption process is found to be the rate limiting step for overall reactions. The adsorption, evaluated by isotherms and thermodynamic parameters is a spontaneous and endothermic process. High-performance liquid chromatography-mass spectrometry (LC-MS) analysis was used to test degraded products in the degradation of DGB by K-nZVI. A removal mechanism based on the adsorption and degradation is proposed, including (i) prompt adsorption of DBG onto the K-nZVI surface, and (ii) oxidation of DBG by hydroxyl radicals at the K-nZVI surface. The application of K-nZVI to treat real wastewater containing azo dyes shows excellent degradation efficiency.
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/J.CHROMA.2003.09.039
Abstract: A simple and fast method for simultaneous separation of nine metal cations Ni2+, Cu2+, Co2+, Zn2+ Cd2+, K+, Na+, Mg2+ and Ca2+, and NH4+ in methanol is reported. The optimization for separation these 10 cations was achieved by using 0.5% acetic acid and 10 mM imidazole as electrolyte. The effects of water and ionic strength in the s le are discussed. The sensitive detection of transition metal ions was accomplished at 191 nm. The optimized method demonstrated high efficiency and good reproducibility, and was applied successfully to the qualitative and quantitative determination of transition metal ions in water s les, chemical reagents, oral zinc gluconate solution and human plasma.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.JCIS.2019.04.078
Abstract: As one of the important contaminants in wastewater, Pb(II) becomes a severe public health problem because of its non-biodegradable and persistent nature. In this study, reduced graphene oxide (RGO) prepared using green tea extract was successfully used to remove Pb(II) from aqueous solutions. A 96.6% of Pb(II) was removed at 10 mg/L Pb(II) and 0.4 g/L RGO with pH 4.5 at 30 °C, and the adsorption of Pb(II) by RGO followed pseudo-second-order kinetics. To confirm the removal mechanism, various methods (Transmission Electron Microscopy, Raman spectroscopy and X-ray diffraction) were used to characterize RGO before and after Pb(II) adsorption. The results showed that the surface of RGO after Pb(II) adsorption became rougher, and the interlayer spacing increased from 0.36 nm to 0.40 nm, indicating that Pb(II) was adsorbed on the surface and between the layers of RGO. Finally, the adsorption mechanism of Pb(II) by RGO was proposed, Pb(II) was adsorbed on the surface of RGO via the electrons on the π-bond on RGO and the interaction of Pb(II) with oxygen-containing functional groups, which were supported by the Fourier Transform Infrared and X-ray photoelectron spectroscopy results.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.ENVPOL.2017.10.114
Abstract: The incorporation of various types of crop straw to agricultural soils has long been practiced to improve soil fertility. However, the effects of crop straw on the fate of organo-chlorine pesticides in flooded paddy soils are not well understood. The dechlorination of pentachlorophenol (PCP) in four vertical profiles (0-10, 10-20, 20-30, 30-50 mm depth) of two flooded paddy soils, a Plinthudult (Soil 1) and a Tropudult (Soil 2) was investigated following the application of four crop straws (rice, wheat, rape and Chinese milk vetch) to them. In all treatments, PCP dechlorination decreased with increasing soil depth. In the crop straw treatments, PCP was almost completely dechlorinated within 60 days, and rapidly transformed to 2,3,4,5-tetrachlorophenol, and further to 3,4,5-trichlorophenol. Further dechlorination of 3,4,5-trichlorophenol also occurred in all treatments except for the rape straw. It is possible that the NH
Publisher: American Chemical Society (ACS)
Date: 06-10-2014
DOI: 10.1021/JF502746N
Abstract: Vertical variations of pentachlorophenol (PCP) dissipation and microbial community were investigated in a paddy soil with the addition of electron acceptors (NO3(-), SO4(2-)) and donors (crop residues). Crop residues enhanced PCP dissipation by supplying dissolved organic carbon (DOC) as an electron donor, whereas NO3(-) and SO4(2-) inhibited it. The dissipation of PCP in electron donor treatments resulted in the accumulation of 3,4,5-trichlorophenol (3,4,5-TCP) except for wheat residues. The abundance and ersity of phospholipid fatty acids (PLFAs) decreased with increasing soil depth. The succession of predominant PLFAs shifted from aerobic bacteria to anaerobic bacteria when electron acceptors were changed to electron donors. The saturated/monounsaturated fatty acids (S/M) ratio increased with soil depth, which probably implied that nutrient turnover rate declined after the accumulation of 3,4,5-TCP. The results showed that the addition of electron donors and acceptors modified the microbial communities, which then further influenced the degradation pathway of PCP.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.CHEMOSPHERE.2019.05.191
Abstract: Extracellular electron transfer from the biofilm surface to the electrode is the key step for the microbial fuel cell (MFC). More recently, graphene has attracted tremendous attentions for bioelectrochemical applications due to its good biocompatibility, high electrical conductivity and large surface area. In the current work, we report a facile and green synthesis of graphene-modified carbon paper (CP) as an efficient MFC anode through plant-mediated bioreduction coupled with self-assembly. Three-dimensional CFP uniformly wrapped by curled and wrinkled biosynthesized graphene enables more surface area for microbe adhesion and mass diffusion. Significantly, nontoxic and biodegradable biomolecules extracted from Eucalyptus leaves act as reducing agent and adsorb on the graphene, rendering the graphene surface become hydrophilic and biocompatible. Furthermore, the obtained graphene exhibit excellent bioelectrochemical interactions with the microbes. Equipped with the biosynthesized graphene-modified anode, the E. coli-catalyzed MFC delivered an enhanced maximum power density of 1158 mW/m
Publisher: Springer Science and Business Media LLC
Date: 18-11-2009
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.JCIS.2021.11.049
Abstract: The presence of residual antibiotics will lead to potential environmental risks. Here cyclodextrins (CDs) were successfully used to modify graphene-based iron nanoparticles (GO@Fe NPs) to enhance the absorption of oxytetracycline hydrochloride (OTC). The removal of OTC decreased in the order: γCD-GO@Fe NPs > βCD-GO@Fe NPs > αCD-GO@Fe NPs > GO@Fe NPs, with better performance than that of bare GO and Fe NPs. Characterization techniques were applied to better understand how CDs impact the structure of GO@Fe NPs and improve removal performance. Raman and X-ray diffraction analysis showed that GO acted as a carrier to support Fe NPs within the grafted cyclodextrin, where GO also participated in the removal process. Cyclodextrin modified GO@Fe NPs had relatively small particle sizes (15 nm), with a high surface area (61.7 m
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.JHAZMAT.2010.06.101
Abstract: Bacterial strains isolated from oil refining wastewater sludge (Fuzhou, China) were used to biodegrade naphthalene in cultured medium. Bacillus fusiformis (BFN) strain was identified using 16S rDNA gene sequence analysis. Optimal conditions for the biodegradation of naphthalene included: temperature of 30 degrees C, pH 7.0, 0.2% inoculum size and a C/N ratio of 1.0. Under these conditions and initial naphthalene concentration of 50 mg/L, more than 99.1% was removed within 96 h. Of those factors influencing the biodegradation of naphthalene, salinity and inoculum concentration were of greatest importance. Furthermore, the biodegradation kinetics of naphthalene corresponded with the first-order rate model. Degradation metabolites identified using GC-MS, included o-phthalic acid and benzoic acid, suggesting possible metabolic pathways. Finally, given these metabolites are water-soluble and non-toxic, the findings suggest a potential bioremediation role of Bacillus fusiformis (BFN) in the removal of naphthalene from wastewaters.
Publisher: Springer Science and Business Media LLC
Date: 27-04-2012
Publisher: Elsevier BV
Date: 11-2002
DOI: 10.1016/S0043-1354(02)00221-X
Abstract: A new liquid chromatographic (LC) method with automated on-line solid phase extraction was developed to determine caffeine at sub-microgram per litre concentrations in waters. The filtered s le was pre-concentrated in a pre-column, which was backwashed with acidic water at pH of 2.70. The concentrated caffeine was separated using a C18 column with a gradient of water-acetonitrile and detected by diode array detection (DAD) at 210 nm. Four different pre-columns: C18, PRP-1, PLRP-s and Env were evaluated for the on-line solid phase extraction of caffeine. The PLRP-s pre-column allowed the enrichment of up to 100 mL of environmental water s le with highest recovery. The procedure was validated by recovery experiments in water spiked at 0.5 1.0 and 4.0 microg/L. Average recoveries were between 92.1 +/- 5.2% and 97.8 +/- 2.6%. Detection limits as low as 0.1 microg/L from 50 ml of s le were achieved. The proposed method has the advantages of higher reliability and sensitivity, simpler s le preparation and shorter analysis time in comparison with off-line solid-phase extraction. The utility of the method was demonstrated at two field sites: Bolivar and Halls Head (Australia). At Bolivar, the treatment process included 6-week lagoon storage which is believed to have attenuated caffeine, and thus limited its use as an environmental tracer of reclaimed water. At the Halls Head site, where the storage period is shorter, caffeine was detected in both the treated sewage effluent and in groundwater near ponds where the reclaimed water is at similar concentrations. These results suggest that the environmental conditions under which caffeine is conservative require better definition.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 07-2011
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.JCIS.2014.04.059
Abstract: Kaolinite supported bimetallic Fe/Ni nanoparticles (K-Fe/Ni) demonstrated capacity for simultaneous removal of both cationic and anionic contaminants such as Pb (II) and NO3(-). The dispersion of Fe/Ni nanoparticles was improved when kaolinite was used as a stabilizer, and also enhanced the reactivity of K-Fe/Ni. The adsorption of Pb (II) onto the kaolinite and the consequent simultaneous catalytic reduction of Pb (II) and NO3(-) kaolinite were confirmed by SEM, BET, EDS, XRD and batch adsorption-reduction test. Orthogonal method showed that initial concentrations of Pb (II) and NO3(-), as well the dosage of K-Fe/Ni showed the most significant impact on the removal rates, where 86.3% of Pb (II) and 73.6% of NO3(-) was removed at optimized conditions. In addition, K-Fe/Ni could be stored for 15 days in dry air without losing reactivity. Reusability test of K-Fe/Ni indicated that the removal efficiency decreased by 12.5% for Pb (II) and 27.2% for NO3(-) after using 3 times successively. Two electroplating wastewater s les were tested and showed K-Fe/Ni could remove more than 96% of Pb (II) and NO3(-) under the optimized conditions.
Publisher: Elsevier BV
Date: 06-2001
Publisher: Wiley
Date: 10-11-2009
DOI: 10.1002/RCM.4321
Abstract: On-line solid-phase extraction (SPE) for pre-concentration and s le cleanup is one strategy to reduce matrix effects and to simultaneously improve detection sensitivity in liquid chromatography/mass spectrometry (LC/MS). This paper describes an on-line SPE-LC/MS method for the determination of tributyltin (TBT) and triphenyltin (TPhT) at trace levels in water s les. The direct coupling of an on-line C18 pre-column to LC/MS was used to pre-concentrate TBT and TPhT at trace levels from waters and to remove interfering matrix effects. Pre-concentration was followed by separation of TBT and TPhT on a C18 column using a mobile phase containing 0.1% (v/v) HCOOH/5 mM HCOONH4 and methanol. While both electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) can be interfaced with MS for the detection of TBT and TPhT, ESI-MS was preferred for this application. The calibration curve for the targets was linear in the concentration range 0.1-30 microg L(-1). The detection limit (signal-to-noise (S/N) ratio = 3) was 0.02 microg L(-1) when 3.0 mL of s le was enriched on the C18 pre-column. The recoveries of TBT and TPhT in spiked waters were from 81.0 to 101.9%. The reproducibilities for the analysis of the standard mixture (10 microg L(-1)) for TBT and TPhT were 13.1 and 5.0%, respectively. The developed method was an easy and fast way to analyze TBT and TPhT in water s les.
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.SCITOTENV.2019.07.090
Abstract: Cadmium (Cd) is a toxic metal ion in pig manure impacting on the ecosystem, and hence the immobilization of Cd by green synthesis of iron nanoparticles (G-nFe) is a potential approach. In this study, transformation of Cd (II) during the pig manure thermophilic aerobic composting process in the presence of G-nFe was investigated. The results show that the addition of G-nFe promoted the composting process and release of available phosphorus (AP). In all six experiments, obvious passivation of Cd occurred during 15 days' composting. Particularly when 500 mL kg
Publisher: Wiley
Date: 12-2008
Abstract: Flow injection analysis (FIA) with ESI-MS and ion chromatography (IC) with inductively coupled plasma-MS (ICP-MS) as the complementary technique have been explored for the determination of metal ions as their metal-EDTA complexes. ESI-MS enabled the identification of metal-EDTA complexes such as [Mn(EDTA)](2-), [Co(EDTA)](2-), [Ni(EDTA)](2-), [Cu(EDTA)](2-), [Zn(EDTA)](2-), [Pb(EDTA)](2-), and [Fe(EDTA)](1-) and their MS spectral showed that these metal-EDTA complexes were present in solution. Based on the ESI-MS, ion chromatographic separation and ICP-MS detection of these complexes are possible because IC-ICP-MS requires stable metal-EDTA complex during the chromatographic separation. The separation of these metal-EDTA complexes was achieved on an anion-exchange column with a mobile phase containing 30 mM NH(4)(HPO(4))(2) at pH 7.5 within 7 min with ICP-MS providing element specific detection. The ICP-MS LODs for the metal-EDTA were in the range of 0.1-0.5 microg/L with the exception of Fe (15 microg/L). The proposed method was a simple procedure for s le processing, using direct injection of s le without removal of s le matrix and was successfully applied to the determination of metal-EDTA complexes in real s les.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CHEMOSPHERE.2019.01.179
Abstract: Aromatic compounds are widely contained in coking wastewater (CWW), drawing great attention due to their potential risks to environment and human health. Integrated systems combining biological processes with advanced treatments are the current trend of CWW reclamation. However, the variations of aromatic composition throughout these processes are poorly understood. This study investigated the occurrence, fate and removal of aromatic compounds in a full scale CWW reclamation plant with eight treatment stages by gas chromatography-mass spectrometry and optical spectrum. The results showed that polycyclic aromatic hydrocarbons (PAHs), phenols and heterocyclic compounds accounted for 38.9%, 33.5% and 22.6% of the total organics in CWW, respectively. Among them, PAHs were more sensitive to anaerobic digestion, while phenols and heterocyclics had higher bioavailability in aerobic process. Although more than 90% DOC could be removed in biological processes, the bio-effluent was still brown in color, implying the residues of aromatics to the advanced treatments. The interaction between the bio-refractory organics and the advanced treatments suggested that multiple aromatic compounds were selectively removed along the treatment train. Specifically, coagulation, sand filtration, ultrafiltration, adsorption, nanofiltration and reverse osmosis were found to be highly related to the elimination of residual isoquinoline, phenol, cresol, fluoranthene, benzene and humic-like organics, correspondingly. Findings in this study indicated that adsorption was a key step for removing chromophoric PAHs with more aromatic rings, while fouling control in the end-point membrane systems should be focused on the elimination of BTEXs and humic-like substances.
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.BIORTECH.2021.126565
Abstract: The laccase enzymatic characteristics and delignification processes of rice straw by Comamonas testosteroni FJ17 were investigated. Artificial intelligence modeling and molecular docking revealed the specific functional properties involved in the interaction between laccase and lignin compounds with a maximum laccase activity of 2016.7 U L
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 12-2008
DOI: 10.1016/J.JCIS.2008.08.066
Abstract: Adsorption of cationic methylene blue and anionic orange II onto unmodified and surfactant-modified zeolites was studied using a batch equilibration method. The effects of equilibrium time, solution pH, and sorption temperature were examined. The results suggested that 2% sodium dodecyl benzenesulfonate (SDBS)- and 3% sodium dodecyl sulfate (SDS)-modified zeolites had higher adsorption capacities for methylene blue than the unmodified zeolite, while 2% cetylpyridinium bromide hexadecyl (CPB)- and 2% hexadecylammonium bromide (HDTMA)-modified zeolites were the best adsorbents for orange II. The adsorption conditions were optimized, and the mechanisms of adsorption are briefly discussed.
Publisher: Elsevier BV
Date: 2023
Publisher: Wiley
Date: 2000
DOI: 10.1002/1099-1565(200011/12)11:6<362::AID-PCA542>3.0.CO;2-U
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.CHEMOSPHERE.2016.05.080
Abstract: This study investigated the use of cetyltrimethylammonium bromide (CTAB) as a stabilizer in green synthesis to improve the reactivity of iron oxide nanoparticles (IONP). Results show that efficiency in removing phosphate increased from 71.0% to 97.3%. To understand how to improve the reactivity of IONP by CTAB: firstly, characterizations of IONP before and after phosphate removal by SEM, EDS, FTIR, XPS show the adsorption of P onto the IONP secondly, batch experiments indicate that the adsorption capacity of phosphate increased when temperature or initial phosphate concentration increased and decreased with an increase in both adsorbent dose and pH. Adsorption followed the pseudo-second-order kinetics model and the equilibrium data fitted well to the Langmuir isotherm. Thermodynamic data confirmed the spontaneous and endothermic nature of the adsorption process. Finally, it was proposed that the adsorption of phosphate using CTAB-modified IONP was mainly associated with inner-sphere complexing mechanism and electrostatic attraction.
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.WATRES.2010.09.025
Abstract: Bentonite-supported nanoscale zero-valent iron (B-nZVI) was synthesized using liquid-phase reduction. The orthogonal method was used to evaluate the factors impacting Cr(VI) removal and this showed that the initial concentration of Cr(VI), pH, temperature, and B-nZVI loading were all importance factors. Characterization with scanning electron microscopy (SEM) validated the hypothesis that the presence of bentonite led to a decrease in aggregation of iron nanoparticles and a corresponding increase in the specific surface area (SSA) of the iron particles. B-nZVI with a 50% bentonite mass fraction had a SSA of 39.94 m(2)/g, while the SSA of nZVI and bentonite was 54.04 and 6.03 m(2)/g, respectively. X-ray diffraction (XRD) confirmed the existence of Fe(0) before the reaction and the presence of Fe(II), Fe(III) and Cr(III) after the reaction. Batch experiments revealed that the removal of Cr (VI) using B-nZVI was consistent with pseudo first-order reaction kinetics. Finally, B-nZVI was used to remediate electroplating wastewater with removal efficiencies for Cr, Pb and Cu > 90%. Reuse of B-nZVI after washing with ethylenediaminetetraacetic acid (EDTA) solution was possible but the capacity of B-nZVI for Cr(VI) removal decreased by approximately 70%.
Publisher: Elsevier BV
Date: 08-2020
Publisher: Springer Science and Business Media LLC
Date: 2003
DOI: 10.1007/S00216-002-1621-3
Abstract: In this paper, the use of an ion-pairing reagent to improve the separation selectivity of inorganic anions in CZE was demonstrated by the addition of tetramethylammonium hydroxide (TMAOH) to the electrolyte. The separation of inorganic anions (Cl(-), I(-), Br(-), NO(2)(-), NO(3)(-) and SCN(-)) was performed using co-electroosmotic flow (EOF) with direct UV detection at 185 nm. The parameters affecting the mobility of the tested anions and the EOF such as the electrolyte pH and concentration of TMAOH in the electrolyte were examined to optimise the separation conditions. In addition, s le-stacking techniques were investigated to improve detection sensitivity. Detection sensitivities were improved 5-13-fold using electrokinetic s le stacking. The detection limits ranged from 1-3 micro mol L(-1). Finally, the proposed method was used for the separation of anions in groundwaters.
Publisher: Elsevier BV
Date: 12-2016
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.ENVPOL.2019.113668
Abstract: Iron nanoparticles (Fe NPs) have often been used for in situ remediation of both groundwater and soil. However, the impact of Fe NPs on the distribution and transformation of As species in contaminated soil is still largely unknown. In this study, green iron oxide nanoparticles synthesized using a euphorbia cochinchinensis leaf extract (GION) were used to stabilize As in a contaminated soil. GION exhibited excellent As stabilization effects, where As in non-specifically-bound and specifically-bound fractions decreased by 27.1% and 67.3% after 120 days incubation. While both arsenate (As (V)) and arsenite (As (III)) decreased after GION application, As (V) remained the dominant species in soil. X-ray photoelectron spectroscopy (XPS) confirmed that As (V) was the dominant species in specifically-bound fractions, while As (III) was the dominant species in amorphous and poorly-crystalline hydrous oxides of Fe and Al. Correlation analysis showed that while highly available As fractions were negatively correlated to oxalate and DCB extractable Fe, they were positively correlated to Fe
Publisher: Elsevier BV
Date: 09-2021
Publisher: Springer Science and Business Media LLC
Date: 05-0004
DOI: 10.1007/BF02467748
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CHEMOSPHERE.2018.06.002
Abstract: Membrane distillation (MD) has been hindered in industrial applications due to the potential wetting or fouling caused by complicated organic compositions. This study investigated the correlations between the fate and wetting potential of bio-refractory organics in the MD process, where three coke wastewater s les pre-treated with bio-degradation and coagulation served as feed solutions. Results showed that although most of the bio-refractory organics in coke wastewater were rejected by the hydrophobic membrane, some volatile aromatic organics including benzenes, phenols, quinolines and naphthalenes passed through the membrane during the MD process. Interestingly, membrane wetting occurred coincidently with the penetration of phenolic and heterocyclic organics. The wetting rate was obviously correlated with the feed composition and membrane surface properties. Ultimately, novel insights into the anti-wetting strategy of MD with bio-refractory organics was proposed, illustrating that the polyaluminum chloride olyacrylamide coagulation not only removed contaminants which could accelerate membrane wetting, but also retarded membrane wetting by the complexation with organics. The deposition of these complexes on the membrane surface introduced a secondary hydrophilic layer on the hydrophobic substrate, which established a composite membrane structure with superior wetting resistance. These new findings would be beneficial to wetting control in membrane distillation for wastewater treatment.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.CHEMOSPHERE.2017.02.079
Abstract: Bioremediation plays an important role in oil spill management and bio-electrochemical treatment systems are supposed to represent a new technology for both effective remediation and energy recovery. Diesel removal rate increased by four times in microbial fuel cells (MFCs) since the electrode served as an electron acceptor, and high power density (29.05 W m
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.SCITOTENV.2019.135002
Abstract: Since elevated levels of common nutrients, such as ammonia and phosphate, in natural water bodies (lakes and rivers) can lead to significant deterioration of pristine water ecosystems due to eutrophication, new and cost-effectiveness remediation strategies are urgently required. This work investigated the feasibility of using green synthesized iron oxide nanoparticles dispersed onto zeolite by eucalyptus leaf extracts (EL-MNP@zeolite), to simultaneously remove ammonia and phosphate from aqueous solutions. SEM and XRD both showed that EL-MNP@zeolite had better stability and dispersity than unsupported zeolite. At an initial concentration of 10 mg L
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.CHEMOSPHERE.2015.07.050
Abstract: The remediation of toxic persistent organic contaminants in the environment has raised a need for effective cleanup methods. In this study, an integrated remediation technique based on biodegradation of naphthalene using Bacillus fusiformis and Fenton oxidation of their degraded metabolites using nanoscale zero-valent iron (nZVI). A 99.0% naphthalene was biodegraded by B. fusiformis in 96h, while only 59.4% chemical oxygen demand (COD) was removed, indicating that the degraded metabolites existed in solution. To further degrade the metabolites, nanoscale zero-valent iron (nZVI) was used as heterogeneous catalyst for Fenton-like oxidation of the metabolites after biodegradation lasting 40h. Results showed that the total the removal COD increased from 36.4% to 91.6% at pH 3.0, 1.0gL(-1) nZVI, 10.0mML(-1) H2O2 and temperature of 35°C. Scanning electron microscopy (SEM) showed the aggregation and corrosion of nZVI. X-ray diffraction (XRD) confirmed the existence of Fe(0) and the presence of iron oxide (Fe(II)) and iron oxohydroxide (Fe(III)). A possible degradation pathway was proposed since two naphthalene metabolites (1-Naphthalenol and 1,4-Naphthalenedione) were detected by GC-MS.
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.JCIS.2011.07.057
Abstract: Zero-valent iron (ZVI) nanoparticles tend to agglomerate, resulting in a significant loss in reactivity. To address this issue, synthesized bentonite-supported nanoscale zero-valent iron (B-nZVI) was used to remove azo dye methyl orange (MO) in aqueous solution. Batch experiments show that various parameters, such as pH, initial concentration of MO, dosage, and temperature, were affected by the removal of MO. Scanning electron microscopy (SEM) confirmed that B-nZVI increased their reactivity and a decrease occurred in the aggregation of iron nanoparticles for the presence of bentonite (B). Using B-nZVI, 79.46% of MO was removed, whereas only 40.03% when using nZVI after reacting for 10 min with an initial MO concentration of 100 mg/L (pH=6.5). Furthermore, after B-nZVI reacted to MO, XRD indicated that iron oxides were formed. FTIR showed that no new bands appeared, and UV-vis demonstrated that the absorption peak of MO was degraded. Kinetics studies showed that the degradation of MO fitted well to the pseudo first-order model. A degradation mechanism is proposed, including the following: oxidation of iron, adsorption of MO to B-nZVI, formation of Fe(II)-dye complex, and cleavage of azo bond. Finally, the removal rate of MO from actual wastewater was 99.75% when utilizing B-nZVI.
Publisher: Elsevier BV
Date: 05-2020
DOI: 10.1016/J.CHEMOSPHERE.2019.125700
Abstract: Anti-tumor drugs, due to their non-specific toxicity will cause long-term delayed toxicity to organisms and humans when discharged into the environment. In this study, reduced graphene oxide @ iron nanoparticles (rGO@Fe NPs) were successfully prepared using green tea extract as reductant and subsequently used for mitoxantrone (MTX) removal. SEM and Raman spectroscopy showed that 30-60 nm sized Fe NPs were loaded on rGO and green tea extract successfully reduced GO to rGO. The removal efficiency of MTX by the hybrid material was higher (98.5%) than either rGO (77.5%) or Fe NPs (53.1%) alone. In addition, the removal efficiency of MTX by the hybrid material was as high as 95% within 5 min, MTX adsorption followed both a pseudo-second-order kinetic model and the Langmuir isotherm, and it is a spontaneous adsorption. Recycling experiments showed that the removal efficiency of MTX decreased from 99.9 to 76.8% after six cycles, and could be as high as 99% in both municipal and medical wastewater. Scanning electron microscopy (SEM), Fourier transform infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and High performance liquid chromatography (HPLC) were all used to characterize and analyze the hybrid material, and possible adsorption mechanisms which revealed that MTX adsorption probably involved a combination of π-π stacking interaction, hydrogen bonding, electrostatic interaction and pore-filling.
Publisher: Elsevier BV
Date: 02-1997
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.CHEMOSPHERE.2017.05.120
Abstract: The treatment of a synthetically prepared wastewater containing diesel oil has been investigated using combined treatment schemes based on the biological treatment followed by an advanced oxidation process. 78% of diesel oil was degraded by Acinetobacter venetianus in 96 h, while the removal efficiency of chemical oxygen demand (COD) in the aqueous phase was only 56.8%, indicating that degraded metabolites existed in solution. To solve this problem, a Fenton-like system consisting of nanoscale zero-valent iron (nZVI) and hydrogen peroxide was used for further oxidation of the metabolites after biodegradation. Results showed that the total COD removal increased from 56.8% to 89% under the optimal condition. In addition, effects of initial pH (2.0-9.0), ZVI dosage (0-2.0 g L-1), hydrogen peroxide (H
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 11-2017
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/J.CHROMA.2003.10.002
Abstract: On-column complexation of Fe2+ and Fe3+ with 2,6-pyridinedicarboxylic acid (2,6-PDCA) formed anionic complexes, which were then separated by capillary zone electrophoresis with direct UV detection at 214 nm. To achieve reasonable separation selectivity and on-column complexation, the conditions such as pH, the concentration of 2,6-PCDA and the EOF modifiers in the electrolyte were examined. The electrolyte contained 5.0 mM 2,6-PDCA, 0.25 mM tetradecyltrimethlammonium bromide (TTAB) and 5% (v/v) acetonitrile at pH 4.0 was optimised for on-column complexation and the separation of Fe[PCDA]2(2-) and Fe[PCDA]2(-). To enhance the detection sensitivity, large-volume s le stacking (LVSS) was used for the on-line preconcentration of Fe[PCDA]2(2-) and Fe[PCDA]2(-). Under the optimised conditions, satisfactory working ranges (0.5-50 microM), lower detection limits (less than 0.1 microM) and good repeatability of the peak areas (R.S.D.: 5.2-7.8%, n = 5) was achieved using LVSS (300 s). With LVSS, the detection sensitivity was enhanced more than 50-fold compared to conventional hydrodynamic injection. The proposed method was used successfully for the determination of Fe2+ and Fe3+ in water s les.
Publisher: Springer Science and Business Media LLC
Date: 21-08-2013
Publisher: Informa UK Limited
Date: 1999
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.ACA.2007.11.013
Abstract: A comprehensive review is presented addressing recent trends in the speciation and determination of vanadium in environmental and biological s le matrices, including important analytical aspects such as s le clean up, pre-concentration and method development. Methodology based on both separation and spectroscopic techniques for the determination of vanadium speciation is discussed. A brief outline of analytical principles, together with an overview of the recent developments and applications of vanadium speciation determination is included. The newer methods for detecting metal ions including hyphenated spectroscopic techniques and s le preparation schemes are also discussed.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2012
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 1997
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.JCIS.2015.01.080
Abstract: Calcium alginate encapsulated Ni/Fe bimetallic nanoparticles beads (CA-Ni/Fe beads) were synthesized to simultaneously remove Cu (II) and monochlorobenzene (MCB) from aqueous solution. SEM, EDS, and XRD analyses confirmed that Ni/Fe bimetallic nanoparticles were not oxidized and successfully encapsulated by calcium alginate (CA). The experiments showed that the encapsulation process improved the simultaneous removal efficiency of Cu (II) and MCB, from 83.9% to 86.7% for Cu (II) and 94.7% to 99.1% for MCB compared with bare Ni/Fe nanoparticles after 120min treatment. Furthermore, the removal efficiency of Cu (II) and MCB increased with higher temperature, calcium alginate: Ni/Fe ratios and pH. Pseudo-second-order model for adsorption and pseudo-first-order model for the reduction process fitted the simultaneous removal of Cu (II) and MCB using CA-Ni/Fe beads. Based on the above results, it could be concluded that the simultaneous removal was a two-step process: firstly, the adsorption of Cu (II) and MCB on the CA-Ni/Fe beads and secondly, reduction of Cu (II) and dehalogenation of MCB by Ni/Fe in CA-Ni/Fe beads. Finally, the efficiency of regenerated CA-Ni/Fe beads was tested using synthesized wastewater which showed a satisfactory removal efficiency of Cu (II) and MCB maintained at 83.8% and 91.7% after three times' regeneration.
Publisher: Wiley
Date: 08-1999
DOI: 10.1046/J.1469-8137.1999.00454.X
Abstract: A centrifugal method for extracting apoplastic sap from roots of lupin ( Lupinus angustifolius ) and pea ( Pisum sativum ) plants, and a method to analyse malic dehydrogenase in the sap using capillary electrophoresis, are described. Osmolality of apoplastic sap was relatively constant at relative centrifugal forces (RCFs) between 600 and 3000 g for lupin, and between 600 and 4000 g for pea. Electropherograms of a marker enzyme (malic dehydrogenase) and other components in apoplastic and symplastic saps revealed that contamination occurred at 7000 g . It is suggested that apoplastic sap expelled from plant roots at RCF between 600 and 3000 g is free from symplastic contamination, and is regarded as being of apoplastic origin. The proposed method was used to measure apoplastic pH changes in the plant roots in response to external pH, ammonium, nitrate and vanadate.
Publisher: Elsevier BV
Date: 06-2014
Publisher: Elsevier BV
Date: 07-2020
Publisher: Wiley
Date: 05-10-2016
Abstract: The discovery of novel drugs against animal parasites is in high demand due to drug-resistance problems encountered around the world. Herein, the synthesis and characterization of 27 organic and organometallic derivatives of the recently launched nematocidal drug monepantel (Zolvix
Publisher: Elsevier BV
Date: 2015
Publisher: Wiley
Date: 11-1997
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 20-02-2011
Publisher: Elsevier BV
Date: 10-2010
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 04-2016
Publisher: Wiley
Date: 28-12-2017
DOI: 10.1002/CEM.2870
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.JHAZMAT.2009.04.092
Abstract: Modified kaolinite clay with 25% (w/w) aluminium sulphate and unmodified kaolin were investigated as adsorbents to remove Pb(II) from aqueous solution. The results show that amount of Pb(II) adsorbed onto modified kaolin (20mg/g) was more than 4.5-fold than that adsorbed onto unmodified kaolin (4.2mg/g) under the optimized condition. In addition, the linear Langmuir and Freundlich models were used to describe equilibrium isotherm. It is observed that the data from both adsorbents fitted well to the Langmuir isotherm. The kinetic adsorption of modified and unmodified kaolinite clay fitted well to the pseudo-second-order model. Furthermore, both modified and unmodified kaolinite clay were characterized by X-ray diffraction, Fourier transform infrared (FT-IR) and scanning electron microscope (SEM). Finally, both modified and unmodified kaolinite clay were used to remove metal ions from real wastewater, and results show that higher amount of Pb(II) (the concentration reduced from 178 to 27.5mg/L) and other metal ions were removed by modified kaolinite clay compared with using unmodified adsorbent (the concentration reduced from 178 to 168 mg/L).
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.SAA.2013.09.054
Abstract: Iron-based nanoparticles (OT-FeNP) were synthesized using oolong tea extracts. Their morphology, structure and size were confirmed by scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-visible (UV-vis) and Fourier Transform Infrared spectroscopy (FTIR). Formation of FeNP results in mostly spherical particles with diameters ranging from 40 to 50 nm. Degradation of malachite green (MG) using OT-FeNP demonstrated that kinetics fitted well to the pseudo first-order reaction by removing 75.5% of MG (50 mg/L). This indicated that OT-FeNP has the potential to serve as a green nanomaterial for environmental remediation.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.SCITOTENV.2019.133878
Abstract: The mixed contamination of environmental matrices by antibacterial agents and heavy metals has attracted much attention worldwide due to the complex nature of their environmental interactions and their potential toxicity. In this work, green synthesized bimetallic iron/nickel nanoparticles (Fe/Ni NPs) was used to simultaneously remove triclosan (TCS) and copper (Cu (II)) under optimal experimental conditions with removal efficiencies of 75.8 and 44.1% respectively. However, in a mixed contaminant system the removal efficiencies of TCS and Cu (II) were lower than when TCS (85.8%) and Cu (II) (52.5%) were removed separately, suggesting that there was competitive relationship between the two contaminants and Fe/Ni NPs used for remediation. SEM-EDS, XRD and FTIR all indicated that both TCS and Cu (II) were adsorbed onto Fe/Ni NPs. Furthermore, while XPS showed that Cu (II) was reduced to Cu
Publisher: Informa UK Limited
Date: 15-03-2011
Start Date: 2008
End Date: 2010
Funder: National Natural Science Foundation of China
View Funded ActivityStart Date: 2005
End Date: 2007
Funder: Australian Research Council
View Funded Activity