T. David Waite

CFD modelling of uneven flows behaviour in flat-sheet membrane bioreactors: From bubble generation to shear stress distribution

Publisher: Elsevier BV

Date: 2019

DOI: 10.1016/J.MEMSCI.2018.10.040

Removal of Trace Uranium from Groundwaters Using Membrane Capacitive Deionization Desalination for Potable Supply in Remote Communities: Bench, Pilot, and Field Scale Investigations

Publisher: American Chemical Society (ACS)

Date: 19-07-2023

DOI: 10.1021/ACS.EST.3C03477

Boron Removal from Reverse Osmosis Permeate Using an Electrosorption Process: Feasibility, Kinetics, and Mechanism

Publisher: American Chemical Society (ACS)

Date: 29-06-2022

DOI: 10.1021/ACS.EST.2C02297

Abstract: Boron is present in the form of boric acid (B(OH)

The role of bacterial and algal exopolymeric substances in iron chemistry

Publisher: Elsevier BV

Date: 07-2015

DOI: 10.1016/J.MARCHEM.2015.03.015

Electrocatalysis of the Oxygen Reduction Reaction by Copper Complexes with Tetradentate Tripodal Ligands

Publisher: American Chemical Society (ACS)

Date: 25-10-2023

DOI: 10.1021/ACS.INORGCHEM.3C02738

Production of a Surface-Localized Oxidant during Oxygenation of Mackinawite (FeS)

Publisher: American Chemical Society (ACS)

Date: 20-12-2019

DOI: 10.1021/ACS.EST.9B03975

Abstract: The oxygenation of mackinawite (FeS) frequently occurs at anoxic-oxic interfaces in both natural and engineered systems such as intertidal sediment, in activated sludge in water treatment processes, and during sulfidized zero-valent iron particle corrosion. During reoxygenation events, FeS may drive a Fenton-like process leading to the production of strong oxidants though the details of this process are poorly understood. In this study, benzoic acid (BA) has been used to probe both the magnitude and identity of these strong oxidants under circumneutral pH conditions. The major product of BA oxidation during FeS oxygenation was found to be 2,5-dihydroxybenzoic acid (2,5-DHBA) rather than monohydroxybenzoic acids identified to be the major products in a range of hydroxyl radical (HO

Response of Microbial Community Function to Fluctuating Geochemical Conditions within a Legacy Radioactive Waste Trench Environment

Publisher: American Society for Microbiology

Date: 09-2017

DOI: 10.1128/AEM.00729-17

Abstract: During the 1960s, small quantities of radioactive materials were codisposed with chemical waste at the Little Forest Legacy Site (Sydney, Australia) in 3-meter-deep, unlined trenches. Chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a 6-week period immediately after a prolonged rainfall event to assess the impact of changing water levels upon the microbial ecology and contaminant mobility. Collectively, results demonstrated that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solid-iron-associated species immediately after the initial rainwater pulse to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the potentially important role that the taxonomically erse microbial community played in this transition. In particular, aerobes dominated in the first day, followed by an increase of facultative anaerobes/denitrifiers at day 4. Toward the mid-end of the s ling period, the functional and taxonomic profiles depicted an anaerobic community distinguished by a higher representation of dissimilatory sulfate reduction and methanogenesis pathways. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs. IMPORTANCE The role of chemical and microbiological factors in mediating the biogeochemistry of groundwaters from trenches used to dispose of radioactive materials during the 1960s is examined in this study. Specifically, chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a 6-week period immediately after a prolonged rainfall event to assess how changing water levels influence microbial ecology and contaminant mobility. Results demonstrate that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solid-iron-associated species immediately after the initial rainwater pulse to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the important role that the taxonomically erse microbial community played in this transition. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs.

Cooperative Co-Activation of Water and Hypochlorite by a Non-Heme Diiron(III) Complex

Publisher: American Chemical Society (ACS)

Date: 07-09-2021

DOI: 10.1021/JACS.1C07669

Abstract: Aqueous solutions of the iron(III) complex of

Impact of ferrous iron dosing on iron and phosphorus solids speciation and transformation in a pilot scale membrane bioreactor

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C9EW00225A

Abstract: Dosing of a pilot scale MBR with a ferrous salt for P removal results in a mix of FePO 4(s) and P adsorbed to amorphous iron oxyhydroxides. Increase in the proportion of FePO 4(s) is desired given the higher ratio of P : Fe in the biosolids produced.

Iron and phosphorus speciation in Fe-conditioned membrane bioreactor activated sludge

Publisher: Elsevier BV

Date: 06-2015

DOI: 10.1016/J.WATRES.2015.02.020

Abstract: Iron dosing of membrane bioreactors (MBRs) is widely used as a means of meeting effluent phosphorus targets but there is limited understanding of the nature of iron and phosphorus-containing solids that are formed within the bioreactor (an important issue in view of the increasing interest in recovering phosphorus from wastewaters). Of particular challenge is the complexity of the MBR system and the variety of reactions that can occur on addition of iron salts to a membrane bioreactor. In this study, the performances of bench scale MBRs with dosing of either ferrous or ferric salts were monitored for a period of four months. The distributions of Fe and P-species in the Fe-conditioned sludges were determined using X-ray absorption spectroscopy (XAS) at the Fe K-edge and the P K-edge. Regardless of whether iron was dosed to the anoxic or aerobic chambers and regardless of whether ferrous (Fe(II)) or ferric (Fe(III)) iron was dosed, iron present in the minerals in the conditioned sludges was consistently in the +III oxidation state. Fitting of the Fe K-edge EXAFS spectra revealed that an Fe(III)-phosphate species was the main Fe species present in all cases with the remaining fraction dominated by lepidocrocite (γ-FeOOH) in the Fe(II)-dosed case and ferrihydrite (am-FeOOH) in the Fe(III)-dosed case. Approximately half the phosphorus in the activated sludge s les was present as a distinct Fe-PO4 mineral (such as strengite or an amorphous ferric hydroxyl phosphate analogue of strengite) and half as phosphorus adsorbed to an iron oxyhydroxide mineral phase indicating that both co-precipitation and adsorption of phosphorus by iron contribute to removal of phosphorus from the MBR supernatant.

Self-Sustained Visible-Light-Driven Electrochemical Redox Desalination

Publisher: American Chemical Society (ACS)

Date: 29-06-2020

DOI: 10.1021/ACSAMI.0C08286

The tortoise versus the hare - Possible advantages of microparticulate zerovalent iron (mZVI) over nanoparticulate zerovalent iron (nZVI) in aerobic degradation of contaminants

Publisher: Elsevier BV

Date: 11-2016

DOI: 10.1016/J.WATRES.2016.09.012

Abstract: A comparative study of the ability of microparticulate zerovalent iron (mZVI) and nanoparticulate zerovalent iron (nZVI) to oxidize a target compound (in this study,

Implication of Non-electrostatic Contribution to Deionization in Flow-Electrode CDI: Case Study of Nitrate Removal From Contaminated Source Waters

Publisher: Frontiers Media SA

Date: 22-03-2019

DOI: 10.3389/FCHEM.2019.00146

Faradaic reactions in capacitive deionization (CDI) - problems and possibilities: A review

Publisher: Elsevier BV

Date: 2018

DOI: 10.1016/J.WATRES.2017.10.024

Abstract: Capacitive deionization (CDI) is considered to be one of the most promising technologies for the desalination of brackish water with low to medium salinity. In practical applications, Faradaic redox reactions occurring in CDI may have both negative and positive effects on CDI performance. In this review, we present an overview of the types and mechanisms of Faradaic reactions in CDI systems including anodic oxidation of carbon electrodes, cathodic reduction of oxygen and Faradaic ion storage and identify their apparent negative and positive effects on water desalination. A variety of strategies including development of novel electrode materials and use of alternative configurations and/or operational modes are proposed for the purpose of mitigation or elimination of the deterioration of electrodes and the formation of byproducts caused by undesired side Faradaic reactions. It is also recognized that Faradaic reactions facilitate a variety of exciting new applications including i) the incorporation of intercalation electrodes to enhance water desalination or to selectively separate certain ions through reversible Faradaic reactions and ii) the use of particular anodic oxidation and cathodic reduction reactions to realize functions such as water disinfection and contaminant removal.

Selective Arsenic Removal from Groundwaters Using Redox-Active Polyvinylferrocene-Functionalized Electrodes: Role of Oxygen

Publisher: American Chemical Society (ACS)

Date: 14-09-2020

DOI: 10.1021/ACS.EST.0C03007

Kinetic Analysis of H₂O₂ Activation by an Iron(III) Complex in Water Reveals a Nonhomolytic Generation Pathway to an Iron(IV)oxo Complex

Publisher: American Chemical Society (ACS)

Date: 04-01-2021

DOI: 10.1021/ACSCATAL.0C02877

Kinetic Modeling of the Electro-Fenton Process: Quantification of Reactive Oxygen Species Generation

Publisher: Elsevier BV

Date: 09-2015

DOI: 10.1016/J.ELECTACTA.2015.06.103

Genomic insights into the Archaea inhabiting an Australian radioactive legacy site

Publisher: Cold Spring Harbor Laboratory

Date: 13-08-2019

DOI: 10.1101/728089

Abstract: During the 1960s, small quantities of radioactive materials were co-disposed with chemical waste at the Little Forest Legacy Site (LFLS, Sydney, Australia). The microbial function and population dynamics in a waste trench during a rainfall event have been previously investigated using shotgun metagenomics. This revealed a broad abundance of candidate and potentially undescribed taxa in this iron-rich, radionuclide-contaminated environment. Here, applying genome-based metagenomic methods, we recovered 37 refined archaeal MAGs (≥50% completeness, ≤10% redundancy) from 10 different major lineages. They were, mainly, included in four DPANN lineages without standing nomenclature (LFWA-I to IV) and Methanoperedenaceae (ANME-2D). While most of the new DPANN lineages show reduced genomes with limited central metabolism typical of other DPANN, the orders under the LFWA-III lineage, ‘ Ca. Gugararchaeales’ and ‘ Ca. Anstonellales’, may constitute distinct orders with a more comprehensive central metabolism and anabolic capabilities within the Micrarchaeota phylum. The new Methanoperedens spp. MAGs, together with previously published data, suggests metal ions as the ancestral electron acceptors during the anaerobic oxidation of methane while the respiration of nitrate/nitrite via molybdopterin oxidoreductases would have been a secondary acquisition. The presence of genes for the biosynthesis of polyhydroxyalkanoates in most Methanoperedens also appears to be a widespread characteristic of the genus for carbon accumulation. We formally propose 22 new candidate taxa based on data analysed in this manuscript, as well as four missing formal taxa definitions and two new candidate species based on extant data. We present evidence of four new DPANN lineages and six non-conspecific Methanoperedens , while exploring their uniqueness, potential role in elemental cycling, and evolutionary history.

Oxidant Generation Resulting from the Interaction of Copper with Menadione (Vitamin K3)–a Model for Metal-mediated Oxidant Generation in Living Systems

Publisher: Elsevier BV

Date: 11-2018

DOI: 10.1016/J.JINORGBIO.2018.08.007

Abstract: The oxidation of hydroquinones is of interest both due to the generation of reactive oxygen species (ROS) and to the implications to trace metal redox state. Menadione (MNQ), a typical toxicant quinone used extensively for studying the mechanisms underlying oxidative stress, is known to be an effective source of exogenous ROS. In this study, the kinetics and mechanism of the oxidation of menadiol (MNH

Investigating the effect of ascorbate on the Fe(II)-catalyzed transformation of the poorly crystalline iron mineral ferrihydrite

Publisher: Elsevier BV

Date: 08-2018

DOI: 10.1016/J.BBAGEN.2018.05.005

Abstract: The inorganic core of the iron storage protein, ferritin, is recognized as being analogous to the poorly crystalline iron mineral, ferrihydrite (Fh). Fh is also abundant in soils where it is central to the redox cycling of particular soil contaminants and trace elements. In geochemical circles, it is recognized that Fh can undergo Fe(II)-catalyzed transformation to form more crystalline iron minerals, vastly altering the reactivity of the iron oxide and, in some cases, the redox poise of the system. Of relevance to both geochemical and biological systems, we investigate here if the naturally occurring reducing agent, ascorbate, can effect such an Fe(II)-catalyzed transformation of Fh at 25 °C and circumneutral pH. The transformation of ferrihydrite to possible secondary Fe(III) mineralization products was quantified using Fourier transform infrared (FTIR) spectroscopy, with supporting data obtained using X-ray absorbance spectroscopy (XAS) and X-ray diffraction (XRD). Whilst the amount of Fe(II) formed in the presence of ascorbate has resulted in Fh transformation in previous studies, no transformation of Fh to more crystalline Fe(III) (oxyhydr)oxides was observed in this study. Further experiments indicated this was due to the ability of ascorbate to inhibit the formation of goethite, lepidocrocite and magnetite. The manner in which ascorbate associated with Fh was investigated using FTIR and total organic carbon (TOC) analysis. The majority of ascorbate was found to adsorb to the Fh surface under anoxic conditions but, under oxic conditions, ascorbate was initially adsorbed then became incorporated within the Fe(III) (oxyhydr)oxide structure (i.e., co-precipitated) over time.

Numerical simulations of impact of membrane module design variables on aeration patterns in membrane bioreactors

Publisher: Elsevier BV

Date: 12-2016

DOI: 10.1016/J.MEMSCI.2016.07.011

Faradaic Reactions in Water Desalination by Batch-Mode Capacitive Deionization

Publisher: American Chemical Society (ACS)

Date: 02-05-2016

DOI: 10.1021/ACS.ESTLETT.6B00124

Key Considerations When Assessing Novel Fenton Catalysts: Iron Oxychloride (FeOCl) as a Case Study

Publisher: American Chemical Society (ACS)

Date: 21-09-2021

DOI: 10.1021/ACS.EST.1C04370

Reductive reactivity of borohydride- and dithionite-synthesized iron-based nanoparticles: A comparative study

Publisher: Elsevier BV

Date: 02-2016

DOI: 10.1016/J.JHAZMAT.2015.10.009

Abstract: In this study sodium dithionite (NaS2O4) and sodium borohydride (NaBH4) were employed as reducing agents for the synthesis of nanosized iron-based particles. The particles formed using NaBH4 (denoted nFe(BH4)) principally contained (as expected) Fe(0) according to XAS and XRD analyses while the particles synthesized using NaS2O4, (denoted nFe(S2O4)) were dominated by the mixed Fe(II)/Fe(III) mineral magnetite (Fe3O4) though with possible presence of Fe(0). The ability of both particles to reduce trichloroethylene (TCE) under analogous conditions demonstrated remarkable differences with nFe(BH4) resulting in complete reduction of 1.5mM of TCE in 2h while nFe(S2O4) were unable to effect complete reduction of TCE in 120 h. Moreover, acetylene was the major reaction product formed in the presence of nFe(S2O4) while the major reaction product formed following reaction with nFe(BH4) was ethylene, which was further reduced to ethane as the reaction proceeded. Considering that effective Pd reduction to Pd(0) requires the presence of Fe(0), this is consistent with our finding that Fe(0) is not the dominant phase formed when employing dithionite as a reducing agent under the conditions employed in this study.

Optimizing the design and synthesis of supported silver nanoparticles for low cost water disinfection

Publisher: American Chemical Society (ACS)

Date: 10-2014

DOI: 10.1021/ES502804A

Abstract: Silver nanoparticles (AgNPs) were successfully synthesized and impregnated on silica using chemical reduction methods. XPS and Ag K-edge XANES analysis revealed that the impregnation of AgNPs onto silica using a chitosan + sodium borohydride (NaBH4) method results in higher silver loading and Ag(0)/Ag(I) ratio compared to that obtained using NH3 + NaBH4/glucose methods. The effects of the dosage of chitosan on silver loading, Ag(I) release, and bactericidal activities of AgNP-impregnated silica were investigated, with results showing that, at high dosages of chitosan, Ag(I) released from AgNP-impregnated silica plays an important role in disinfection, while AgNP-mediated bactericidal action dominates at low dosages of chitosan. To further decrease the manufacturing cost, partially oxidized "black rice husk ash" containing substantial residual carbon was applied as AgNP support and found to lead to a greater degree of silver impregnation and to exhibit a longer disinfection lifetime than that of lower carbon content silica supports. On the basis of these findings, it is clear that considerable scope exists for careful optimization in the design and production of AgNP-based bactericidal materials for water treatment purposes.

Phosphate selective recovery by magnetic iron oxide impregnated carbon flow-electrode capacitive deionization (FCDI)

Publisher: Elsevier BV

Date: 02-2021

DOI: 10.1016/J.WATRES.2020.116653

Comparative Experimental and Computational Studies of Hydroxyl and Sulfate Radical-Mediated Degradation of Simple and Complex Organic Substrates

Publisher: American Chemical Society (ACS)

Date: 13-05-2022

DOI: 10.1021/ACS.EST.2C00686

Abstract: Persulfate (PS)-based advanced oxidation processes (AOPs) have been promoted as alternatives to H

The effect of Vitamin C and iron on dopamine-mediated free radical generation: Implications to Parkinson's disease

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C7DT04373B

Abstract: While the application of Asc alone may aggravate the progression of PD in view of the possible peroxidation of Asc bound Fe( ii ), a combination therapy of Asc and strong clinically appropriate iron chelator would appear to be a promising direction for the treatment of PD as a result of the enhanced iron chelation and attenuation in oxidative stress and toxicity induced by DA derived quinones.

Kinetic Modeling-Assisted Mechanistic Understanding of the Catalytic Ozonation Process Using Cu-Al Layered Double Hydroxides and Copper Oxide Catalysts

Publisher: American Chemical Society (ACS)

Date: 16-09-2021

DOI: 10.1021/ACS.EST.1C03718

Effect of Structural Transformation of Nanoparticulate Zero-Valent Iron on Generation of Reactive Oxygen Species

Publisher: American Chemical Society (ACS)

Date: 18-03-2016

DOI: 10.1021/ACS.EST.5B04988

Abstract: While it has been recognized for some time that addition of nanoparticlate zerovalent iron (nZVI) to oxygen-containing water results in both corrosion of Fe(0) and oxidation of contaminants, there is limited understanding of either the relationship between transformation of nZVI and oxidant formation or the factors controlling the lifetime and extent of oxidant production. Using Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, we show that while nZVI particles are transformed to ferrihydrite then lepidocrocite in less than 2 h, oxidant generation continues for up to 10 h. The major products (Fe(II) and H2O2) of the reaction of nZVI with oxygenated water are associated, for the most part, with the surface of particles present with these surface-associated Fenton reagents inducing oxidation of a target compound (in this study, (14)C-labeled formate). Effective oxidation of formate only occurred after formation of iron oxides on the nZVI surface with the initial formation of high surface area ferrihydrite facilitating rapid and extensive adsorption of formate with colocation of this target compound and surface-associated Fe(II) and H2O2 apparently critical to formate oxidation. Ongoing formate oxidation long after nZVI is consumed combined with the relatively slow consumption of Fe(II) and H2O2 suggest that these reactants are regenerated during the nZVI-initiated heterogeneous Fenton process.

Chlorine-Mediated Regeneration of Semiconducting AgCl(s) Following Light-Induced Ag⁰ Formation: Implications to Contaminant Degradation

Publisher: American Chemical Society (ACS)

Date: 11-03-2016

DOI: 10.1021/ACS.JPCC.5B11273

Self-Enhanced Decomplexation of Cu-Organic Complexes and Cu Recovery from Wastewaters Using an Electrochemical Membrane Filtration System

Publisher: American Chemical Society (ACS)

Date: 26-10-2020

DOI: 10.1021/ACS.EST.0C05554

Mechanistic and kinetic insights into the ligand-promoted depassivation of bimetallic zero-valent iron nanoparticles

Publisher: Royal Society of Chemistry (RSC)

Date: 2016

DOI: 10.1039/C6EN00071A

Abstract: Little attention has been given to either the thermodynamics and kinetics of palladium-doped nanoscale zero-valent iron particles (Pd-nZVI) depassivation process or the effect of the presence of co-existent cations using ligand-assisted performance improvement strategies.

Contaminant Removal from Source Waters Using Cathodic Electrochemical Membrane Filtration: Mechanisms and Implications

Publisher: American Chemical Society (ACS)

Date: 15-02-2017

DOI: 10.1021/ACS.EST.6B05625

Abstract: Removal of recalcitrant anthropogenic contaminants from water calls for the development of cost-effective treatment technologies. In this work, a novel electrochemical membrane filtration (EMF) process using a conducting microfiltration membrane as the cathode has been developed and the degradation of sulphanilic acid (SA) examined. The electrochemical degradation of SA in flow-by mode followed pseudo-first-order kinetics with the degradation rate enhanced with increase in charging voltage. Hydrogen peroxide as well as oxidants such as HO

Mechanism Underlying the Effectiveness of Deferiprone in Alleviating Parkinson's Disease Symptoms

Publisher: American Chemical Society (ACS)

Date: 30-01-2018

DOI: 10.1021/ACSCHEMNEURO.7B00478

Abstract: Elevation in iron content as well as severe depletion of dopamine (DA) as a result of iron-induced loss of dopaminergic neurons has been recognized to accompany the progression of Parkinson's disease (PD). To better understand the mechanism of the mitigating effect of the iron chelator deferiprone (DFP) on PD, the interplay between iron and DFP was investigated both in the absence and presence of DA. The results show that DFP was extremely efficient in scavenging both aqueous iron and iron that was loosely bound to DA with the entrapment of iron in Fe-DFP complexed form critical to halting the iron catalyzed degradation of DA and associated generation of toxic metabolites. The DFP related scavenging of dopamine semiquinone (DA

Sulfonamido-Pincer Complexes of Cu(II) and the Electrocatalysis of O₂ Reduction

Publisher: American Chemical Society (ACS)

Date: 03-08-2023

DOI: 10.1021/ACS.INORGCHEM.3C01262

Investigation of pH-dependent phosphate removal from wastewaters by membrane capacitive deionization (MCDI)

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7EW00138J

Abstract: Membrane capacitive deionization (MCDI) is a promising technology for the removal of charged species from aqueous feed streams.

Challenges Relating to the Quantification of Ferryl(IV) Ion and Hydroxyl Radical Generation Rates Using Methyl Phenyl Sulfoxide (PMSO), Phthalhydrazide, and Benzoic Acid as Probe Compounds in the Homo

Publisher: American Chemical Society (ACS)

Date: 31-01-2023

DOI: 10.1021/ACS.EST.2C06753

Effect of Chloride and Suwannee River Fulvic Acid on Cu Speciation: Implications to Cu Redox Transformations in Simulated Natural Waters

Publisher: American Chemical Society (ACS)

Date: 30-01-2020

DOI: 10.1021/ACS.EST.9B06789

Abstract: Copper is a critical trace nutrient and, at higher concentrations, a toxicant in natural waters, with the relative rates of transformation between the Cu(I) and Cu(II) oxidation states being key to its speciation, bioavailability, and toxicity. While the influence of chloride (Cl

Effect of chloride driven copper redox cycling on the kinetics of Fe(II) oxidation in aqueous solutions at pH 6.5-8.0

Publisher: Elsevier BV

Date: 07-2015

DOI: 10.1016/J.GCA.2015.03.035

Hydroxyl Radical Production via a Reaction of Electrochemically Generated Hydrogen Peroxide and Atomic Hydrogen: An Effective Process for Contaminant Oxidation?

Publisher: American Chemical Society (ACS)

Date: 20-04-2022

DOI: 10.1021/ACS.EST.2C00405

Abstract: An electrochemical advanced oxidation process (EAOP) is demonstrated with a catalytic cathode capable of simultaneously catalyzing the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR) with resultant in situ generation of atomic hydrogen (H*) and hydrogen peroxide (H

Effect of release of dopamine on iron transformations and reactive oxygen species (ROS) generation under conditions typical of coastal waters

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C7EM00497D

Abstract: Release of dopamine by Ulvaria obscura var. blyttii may, allelopathically, assist Ulvaria growth by H 2 O 2 generation and benefit the bloom region through alleviation in iron stress and by mitigating the effects of other oxidative metabolites.

Phosphate recovery as vivianite using a flow-electrode capacitive desalination (FCDI) and fluidized bed crystallization (FBC) coupled system

Publisher: Elsevier BV

Date: 04-2021

DOI: 10.1016/J.WATRES.2021.116939

Ammonia-Rich Solution Production from Wastewaters Using Chemical-Free Flow-Electrode Capacitive Deionization

Publisher: American Chemical Society (ACS)

Date: 07-03-2019

DOI: 10.1021/ACSSUSCHEMENG.9B00314

Comparison of Faradaic reactions in capacitive deionization (CDI) and membrane capacitive deionization (MCDI) water treatment processes

Publisher: Elsevier BV

Date: 09-2017

DOI: 10.1016/J.WATRES.2017.05.009

Abstract: Capacitive deionization (CDI) and membrane capacitive deionization (MCDI) are the most common cell architectures in the use of CDI for water treatment. In this work, the Faradaic reactions occurring in batch-mode CDI and MCDI processes were compared by investigating the variation of H

Capacitive Membrane Stripping for Ammonia Recovery (CapAmm) from Dilute Wastewaters

Publisher: American Chemical Society (ACS)

Date: 27-12-2018

DOI: 10.1021/ACS.ESTLETT.7B00534

Heterogeneous Fenton Chemistry Revisited: Mechanistic Insights from Ferrihydrite-Mediated Oxidation of Formate and Oxalate

Publisher: American Chemical Society (ACS)

Date: 27-05-2021

DOI: 10.1021/ACS.EST.1C00284

Continuous Ammonia Recovery from Wastewaters Using an Integrated Capacitive Flow Electrode Membrane Stripping System

Publisher: American Chemical Society (ACS)

Date: 21-11-2018

DOI: 10.1021/ACS.EST.8B02743

Abstract: We have previously described a novel flow-electrode capacitive deionization (FCDI) unit combined with a hydrophobic gas-permeable hollow fiber membrane contactor (designated "CapAmm") and presented results showing efficient recovery of ammonia from dilute synthetic wastewaters (Zhang et al., Environ. Sci. Technol. Lett. 2018, 5, 43-49). We extend this earlier study here with description of an FCDI system with integrated flat sheet gas permeable membrane with comprehensive assessment of ammonia recovery performance from both dilute and concentrated wastewaters. The integrated CapAmm cell exhibited excellent ammonia removal and recovery efficiencies (up to ∼90% and ∼80% respectively). The energy consumptions for ammonia recovery from low-strength (i.e., domestic) and high-strength (i.e., synthetic urine) wastewaters were 20.4 kWh kg

Ligand-mediated contaminant degradation by bare and carboxymethyl cellulose-coated bimetallic palladium-zero valent iron nanoparticles in high salinity environments

Publisher: Elsevier BV

Date: 03-2019

DOI: 10.1016/J.JES.2018.09.002

Abstract: The application of nanoscale zero-valent iron (nZVI) for the degradation of contaminants has been extensively investigated, however, few studies have focused on degradation in high salinity environments. In this study, the ability of bare and carboxymethyl cellulose (CMC)-coated bimetallic Pd-nZVI particles to degrade 33'44'-tetrachlorobiphenyl in high saline water (SW) is examined with particular attention given to the effects of ethylenediaminetetraacetic acid (EDTA) on the rate of degradation. EDTA enhances the reactivity of Pd-nZVI in SW, with evidence provided to link this to the removal of the passivating layer. Additionally, a conceptual model is proposed which provides a quantitative description of the removal of these iron oxide layers in the presence of EDTA. An optimum EDTA to bare Pd-nZVI molar ratio of 0.1 exists, with insufficient EDTA unable to remove the passivating layer whilst excess EDTA results in Fe loss and enhanced agglomeration due to magnetic attraction of the bare Fe(0) particles. In contrast, CMC-coating of Pd-nZVI assemblages actually impedes degradation, despite the coated particles displaying a smaller average size compared to uncoated particles, with even the presence of EDTA in this case not significantly improving degradation. The reduced reactivity in the presence of CMC is primarily attributed to the effect of CMC on the association of Pd with nZVI particles. In particular, the presence of CMC reduced the total amount of Pd incorporated with the stabilized particles compared to the non-stabilized particles. Additionally, the presence of CMC results in less Pd present in its reactive zero-valent oxidation state.

Numerical simulation of bubble induced shear inmembrane bioreactors: Effects of mixed liquor rheology and membrane configuration

Publisher: Elsevier BV

Date: 05-2015

DOI: 10.1016/J.WATRES.2015.02.009

Abstract: A CFD model, incorporating an empirically determined rheology model and a porous media model, was developed to simulate bubble induced surface shear in membrane bioreactors configured with hollow fibre membranes with outer diameters ranging from 1.3 to 2.4 mm, arranged in vertically orientated modules with packing density from 200 to 560 m(2)/m(3). The rheology model was developed for mixed liquor suspended solids (MLSS) concentrations of 3 to 16 gL(-1) in the presence and absence of coagulant (generated by addition of a ferrous salt) for shear rates ranging from 0 to 500 s(-1). Experimentally determined particle relaxation times for the biological flocs in the mixed liquor, both in the absence and presence of iron, were negligible, consistent with an environment where positive buoyancy forces were greater than negative settling forces thereby allowing the sludge mixture to be modelled as a single continuous phase. The non-Newtonian behaviour of the mixed liquor was incorporated into the CFD simulations using an Ostwald-de Waele rheology model. Interactions between mixed liquor and hollow fibre membranes of different fibre size and packing density were described using a porous media model that was calibrated by empirical measurement of inertial loss coefficients over a range of viscosities (0.8 × 10(-3) to 2.1 × 10(-3) Pa.s) and velocities (0 to 0.35 m/s) typically encountered in full scale MBRs. Experimental results indicated that addition of iron salts resulted in an increase in MLSS and sludge viscosity. Shear stress is affected by both velocity and viscosity. The increase in sludge viscosity resulted in an increase in resistance to flow through the hollow fibre membrane bundles and, as a result, decreased the liquid flow velocities. CFD simulations provided insight on the effects of point of coagulant addition and MLSS concentration on bubble-induced shear over a range of industrially relevant conditions. A 12% increase in shear stress was observed when ferrous salts were added to the membrane filtration zone compared to addition to the primary anoxic zone. The presence of iron salts also improved the distribution of shear stress especially at the lower zone of the membrane module. The CFD models developed here were validated using Particle Image Velocimetry (PIV) with the average difference between simulated liquid velocities and PIV measured velocities found to be 5.5%.

A Novel Integrated Flow-Electrode Capacitive Deionization and Flow Cathode System for Nitrate Removal and Ammonia Generation from Simulated Groundwater

Publisher: American Chemical Society (ACS)

Date: 18-09-2023

DOI: 10.1021/ACS.EST.3C03922

Kinetic modeling of pH-dependent oxidation of dopamine by iron and its relevance to Parkinson's disease

Publisher: Frontiers Media SA

Date: 26-11-2018

DOI: 10.3389/FNINS.2018.00859

Insufficient desorption of ions in constant-current membrane capacitive deionization (MCDI): Problems and solutions

Publisher: Elsevier BV

Date: 08-2023

DOI: 10.1016/J.WATRES.2023.120273

Mechanistic insights into the catalytic ozonation process using iron oxide-impregnated activated carbon

Publisher: Elsevier BV

Date: 06-2020

DOI: 10.1016/J.WATRES.2020.115785

Modified Double Potential Step Chronoamperometry (DPSC) Method for As(III) Electro-oxidation and Concomitant As(V) Adsorption from Groundwaters

Publisher: American Chemical Society (ACS)

Date: 23-07-2019

DOI: 10.1021/ACS.EST.9B01762

Abstract: Constrained by low energy efficiency and ineffectiveness in As(III) removal under circumneutral pH conditions by many exsiting technologies, As(III) removal has become an issue. In this work we present proof of concept of a modified double potential step chrono erometry (DPSC) method of As(III) oxidation and concomitant As(V) electro-sorption from aqueous solution. Results show that in situ anodic As(III) oxidation, As(V) electro-sorption, and As(V) electro-desorption are affected by aqueous pH with high oxidation and sorption/desorption rates observed at the elevated pH. We particularly show that effective As(III) oxidation and concomitant As(V) adsorption are related to (i) the rapid oxidation of the deprotonated species compared to the protonated species and (ii) stronger electrochemical interaction between the multicharged As(V) species and the electrodes. At 1.2 V and an electric energy consumption of 0.06 kWh m

Effects of Good’s Buffers and pH on the Structural Transformation of Zero Valent Iron and the Oxidative Degradation of Contaminants

Publisher: American Chemical Society (ACS)

Date: 25-01-2018

DOI: 10.1021/ACS.EST.7B04030

Abstract: The presence of Good's buffers caused rapid ZVI corrosion and a dramatic release of Fe(II) leading to the Fe(II)-catalyzed transformation of ferrihydrite to lepidocrocite and/or the direct formation of lepidocrocite from the oxidation of Fe(II) in the pH range 4.0-6.2. In comparison, in the absence of Good's buffers, elution of Fe(II) was insignificant with ferrihydrite being the only Fe(III) oxyhydroxide detected following the oxidative transformation of ZVI. The rapid ZVI corrosion in the presence of Good's buffer is possibly due to either (i) disruption of the Fe oxide surface layer as a result of attack by Good's buffers and/or (ii) interaction of Good's buffer with the outer Fe oxide surface and surface-associated Fe(II)/Fe(III) causing the Fe oxide surface layers to be more porous with both these processes facilitating continuous O

Computational fluid dynamics (CFD) analysis of membrane reactors: modelling of membrane bioreactors for municipal wastewater treatment

Publisher: Elsevier

Date: 2013

DOI: 10.1533/9780857097330.3.532

Contaminant degradation by irradiated semiconducting silver chloride particles: Kinetics and modelling

Publisher: Elsevier BV

Date: 05-2015

DOI: 10.1016/J.JCIS.2014.11.069

Abstract: The kinetics and mechanism of light-mediated formic acid (HCOO(-)) degradation in the presence of semiconducting silver chloride particles are investigated in this study. Our experimental results show that visible-light irradiation of AgCl(s) results in generation of holes and electrons with the photo-generated holes and its initial oxidation product carbonate radical, oxidizing HCOO(-) to form CO2. The HCOO(-) degradation rate increases with increase in silver concentration due to increase in rate of photo-generation of holes while the increase in chloride concentration decreases the degradation rate of HCOO(-) as a result of the scavenging of holes by Cl(-), thereby resulting in decreased holes and carbonate radical concentration. The results obtained indicate that a variety of other solution conditions including dioxygen concentration, bicarbonate concentration and pH influence the availability of holes and hence the HCOO(-) degradation rate in a manner consistent with our understanding of key processes. Based on our experimental results, we have developed a kinetic model capable of predicting AgCl(s)-mediated HCOO(-) photo-degradation over a wide range of conditions.

Uranium Binding Mechanisms of the Acid-Tolerant Fungus Coniochaeta fodinicola

Publisher: American Chemical Society (ACS)

Date: 09-07-2015

DOI: 10.1021/ACS.EST.5B01342

Abstract: The uptake and binding of uranium [as (UO2)(2+)] by a moderately acidophilic fungus, Coniochaeta fodinicola, recently isolated from a uranium mine site, is examined in this work in order to better understand the potential impact of organisms such as this on uranium sequestration in hydrometallurgical systems. Our results show that the viability of the fungal biomass is critical to their capacity to remove uranium from solution. Indeed, live biomass (viable cells based on vital staining) were capable of removing ∼16 mg U/g dry weight in contrast with dead biomass (autoclaved) which removed ∼45 mg U/g dry weight after 2 h. Furthermore, the uranium binds with different strength, with a fraction ranging from ∼20-50% being easily leached from the exposed biomass by a 10 min acid wash. Results from X-ray absorption spectroscopy measurements show that the strength of uranium binding is strongly influenced by cell viability, with live cells showing a more well-ordered uranium bonding environment, while the distance to carbon or phosphorus second neighbors is similar in all s les. When coupled with time-resolved laser fluorescence and Fourier transformed infrared measurements, the importance of organic acids, phosphates, and polysaccharides, likely released with fungal cell death, appear to be the primary determinants of uranium binding in this system. These results provide an important progression to our understanding with regard to uranium sequestration in hydrometallurgical applications with implications to the unwanted retention of uranium in biofilms and/or its mobility in a remediation context.

pH Dependence of Hydroxyl Radical, Ferryl, and/or Ferric Peroxo Species Generation in the Heterogeneous Fenton Process

Publisher: American Chemical Society (ACS)

Date: 29-12-2021

DOI: 10.1021/ACS.EST.1C05722

Abstract: The heterogeneous Fenton process in the presence of Fe-containing minerals is ubiquitous in nature and widely deployed in wastewater treatment. While there have been extensive relevant studies, the dependence on pH of the nature and extent of oxidant generation and key reaction pathways remain unclear. Herein, the adsorption and decomposition of formate and H

Comparison of Performance of Conventional Ozonation and Heterogeneous Catalytic Ozonation Processes in Phosphate- and Bicarbonate-Buffered Solutions

Publisher: American Chemical Society (ACS)

Date: 05-01-2022

DOI: 10.1021/ACSESTENGG.1C00350

Effect of ferric and ferrous iron addition on phosphorus removal and fouling in submerged membrane bioreactors

Publisher: Elsevier BV

Date: 02-2015

DOI: 10.1016/J.WATRES.2014.11.011

Abstract: The effect of continuously dosing membrane bioreactors (MBRs) with ferric chloride (Fe(III)) and ferrous sulphate (Fe(II)) on phosphorus (P) removal and membrane fouling is investigated here. Influent phosphorus concentrations of 10 mg/L were consistently reduced to effluent concentrations of less than 0.02 mg/L and 0.03-0.04 mg/L when an Fe(III)/P molar ratio of 4.0 and Fe/P molar ratio (for both Fe(II) and Fe(III)) of 2.0 were used, respectively. In comparison, effluent concentrations did not decrease below 1.35 mg/L in a control reactor to which iron was not added. The concentrations of supernatant organic compounds, particularly polysaccharides, were reduced significantly by iron addition. The sub-critical fouling time (tcrit) after which fouling becomes much more severe was substantially shorter with Fe(III) dosing (672 h) than with Fe(II) dosing (1200-1260 h) at Fe/P molar ratios of 2.0 while the control reactor (no iron dosing) exhibited a tcrit of 960 h. Not surprisingly, membrane fouling was substantially more severe at Fe/P ratios of 4. Fe(II) doses yielding Fe/P molar ratios of 2 or less with dosing to the aerobic chamber were found to be optimal in terms of P removal and fouling mitigation performance. In long term operation, however, the use of iron for maintaining appropriately low effluent P concentrations results in more severe irreversible fouling necessitating the application of an effective membrane cleaning regime.

Flow-electrode capacitive deionization (FCDI) scale-up using a membrane stack configuration

Publisher: Elsevier BV

Date: 2020

DOI: 10.1016/J.WATRES.2019.115186

Abstract: Flow-electrode capacitive deionization (FCDI) is an attractive variant of CDI with distinct advantages over fixed electrode CDI including the capability for seawater desalination, high flow efficiency and easy management of the electrodes. Challenges exist however in increasing treatment capacity with this attempted here through use of a membrane stack configuration. By comparison of standardised metrics (in particular, average salt removal rate (ASRR), energy normalized removed salt (ENRS) and productivity), results show that that an FCDI system with two pairs of ion exchange membranes had the highest efficiency in desalting a brackish influent (1000 mg L

Effect of Shewanella oneidensis on the Kinetics of Fe(II)-Catalyzed Transformation of Ferrihydrite to Crystalline Iron Oxides

Publisher: American Chemical Society (ACS)

Date: 20-12-2017

DOI: 10.1021/ACS.EST.7B05098

Abstract: Iron (oxyhydr)oxides are widespread in natural and engineered systems, potent adsorbents of contaminants and a source of energy for iron-reducing bacteria. Microbial reduction of iron (oxyhydr)oxides results in the formation of Fe(II) which can induce the transformation of these iron minerals, typically from less crystalline to more crystalline forms, affecting the biogeochemical cycling of iron and the behavior of any species adsorbed to the iron (oxyhydr)oxides. Factors influencing the transformation rate of the poorly crystalline iron (oxyhydr)oxide, ferrihydrite, to more crystalline forms in the presence of the iron reducing bacterium Shewanella oneidensis MR-1 are investigated under controlled laboratory conditions in this work. In particular, the amount of Fe(II) produced increased the transformation rate while increasing concentrations of the electron donor, lactate, decreased the rate. Using kinetic parameters determined from abiotic controls, the results of transformation experiments in the presence of Shewanella oneidensis were modeled with this exercise revealing that less goethite and more lepidocrocite formed than expected. Conversely, studies using the Shewanella exudate only, containing biogenic Fe(II), displayed rates of transformation that were satisfactorily modeled using these abiotic control kinetic parameters. This result suggests that the physical presence of the microbes is pivotal to the reduction in ferrihydrite transformation rate observed in the biotic experiments relative to the analogous abiotic controls.

Scale-up and Modelling of Flow-electrode CDI Using Tubular Electrodes

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.WATRES.2021.117498

Ascorbic acid-mediated reductive cleaning of iron-fouled membranes from submerged membrane bioreactors

Publisher: Elsevier BV

Date: 03-2015

DOI: 10.1016/J.MEMSCI.2014.11.040

Flow anodic oxidation: Towards high-efficiency removal of aqueous contaminants by adsorbed hydroxyl radicals at 1.5 V vs SHE

Publisher: Elsevier BV

Date: 07-2021

DOI: 10.1016/J.WATRES.2021.117259

Comparison of faradaic reactions in flow-through and flow-by capacitive deionization (CDI) systems

Publisher: Elsevier BV

Date: 03-2019

DOI: 10.1016/J.ELECTACTA.2019.01.058

Silver sulfide nanoparticles in aqueous environments: formation, transformation and toxicity

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C9EN00138G

Abstract: Formation and transformation of silver sulfide nanoparticles occur in both engineered and natural water systems with potential toxic effects to aqueous organisms.

Analysis of capacitive and electrodialytic contributions to water desalination by flow-electrode CDI

Publisher: Elsevier BV

Date: 11-2018

DOI: 10.1016/J.WATRES.2018.07.049

Abstract: While flow-electrode capacitive deionization (FCDI) is a potential alternative to brackish and/or sea water desalination, there is limited understanding of both the fate of ions following migration across the ion exchange membranes and the mechanisms responsible for ion separation. In this study, we investigate the desalting performance of an FCDI system operated over a range of conditions. Results show that although ion transport as a result of electrodialysis is inevitable in FCDI (and is principally responsible for pH excursion in the flow electrode), the use of high carbon content ensures that a high proportion of the charge and counterions are retained in the electrical double layers of the flowing carbon particles, even at high charging voltages (e.g., 2.0 V) during the deionization process. Estimation of the portions of sodium and chloride ions adsorbed in the flow electrode after migration through the membranes suggests that the ongoing capacitive adsorption exhibits asymmetric behavior with the anodic particles demonstrating better affinity for Cl

Manipulation of planar oxygen defect arrangements in multifunctional magnèli titanium oxide hybrid systems: from energy conversion to water treatment

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0EE02550J

Abstract: This work demonstrates that the layer structured Magnèli titanium oxides possess co-existing functionalities, which can be applied to both energy harvesting and water treatment using one material.

pH-dependence of production of oxidants (Cu(III) and/or HO^•) by copper-catalyzed decomposition of hydrogen peroxide under conditions typical of natural saline waters

Publisher: Elsevier BV

Date: 07-2018

DOI: 10.1016/J.GCA.2018.04.016

Water Recovery Rate in Short-Circuited Closed-Cycle Operation of Flow-Electrode Capacitive Deionization (FCDI)

Publisher: American Chemical Society (ACS)

Date: 05-11-2019

DOI: 10.1021/ACS.EST.9B03263

Abstract: While flow-electrode CDI is a promising desalination technology that has major advantages when the electrodes are operated in the short-circuited closed-cycle (SCC) mode, little attention has been paid to the water recovery rate, which, in the SCC mode, is determined by the need for partial replacement of the saline electrolyte of the flow electrodes. Results of this study show that an extremely high water recovery rate of ∼95% can be achieved when desalting a 1000 mg NaCl L

Flow Electrode Capacitive Deionization (FCDI): Recent Developments, Environmental Applications, and Future Perspectives

Publisher: American Chemical Society (ACS)

Date: 16-03-2021

DOI: 10.1021/ACS.EST.0C06552

Redox- and EPR-Active Graphene Diiron Complex Nanocomposite.

Publisher: American Chemical Society (ACS)

Date: 30-08-2019

DOI: 10.1021/ACS.LANGMUIR.9B01526

Abstract: A mixed valence diiron(II/III) complex with the ligand 2,6-bis{bis[(2-pyridinylmethyl)amino]methyl}phenol (bppH) has been covalently anchored onto graphene using a mild in situ microwave-assisted diazonium coupling through an aryl amino precursor and isoamyl nitrite. A dinuclear iron complex is then formed by complexation of the grafted bppH-graphene material with iron(II) in the presence of dioxygen. X-ray photoelectron spectroscopy (XPS), atomic force microscopy, cyclic voltammetry, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy confirm the formation of the anchored ligand and derivative diiron complexes. Semiquantitative XPS analysis shows an average bppH ligand bulk loading of 0.33 mmol/g, corresponding to a significant 20.7 wt % of the functionalized material consisting of grafted moieties. EPR measurements reveal the existence of a strong isotropic

Uranium extraction from a low-grade, stockpiled, non-sulfidic ore: Impact of added iron and the native microbial consortia

Publisher: Elsevier BV

Date: 2017

DOI: 10.1016/J.HYDROMET.2016.11.002

Low cost desalination of brackish groundwaters by Capacitive Deionization (CDI) – Implications for irrigated agriculture

Publisher: Elsevier BV

Date: 03-2019

DOI: 10.1016/J.DESAL.2018.12.001

Development of a Mechanically Flexible 2D-MXene Membrane Cathode for Selective Electrochemical Reduction of Nitrate to N₂: Mechanisms and Implications

Publisher: American Chemical Society (ACS)

Date: 16-06-2021

DOI: 10.1021/ACS.EST.1C00264

Fluoride and nitrate removal from brackish groundwaters by batch-mode capacitive deionization

Publisher: Elsevier BV

Date: 11-2015

DOI: 10.1016/J.WATRES.2015.08.012

Abstract: Capacitive deionization (CDI) is an emerging water desalination technology in which pairs of porous electrodes are electrically charged to remove ionic species from water. In this work, the feasibility of fluoride and nitrate removal from brackish groundwaters by batch-mode CDI was investigated. Initially, the effects of flow rate, initial fluoride concentration, and initial coexisting NaCl concentration on fluoride removal were studied. The steady-state fluoride concentration declined as the initial fluoride concentration decreased while initial NaCl concentration remained constant. Due to the competitive electrosorption between fluoride and chloride for limited pore surface sites, a higher initial chloride concentration resulted in a higher equilibrium dissolved fluoride concentration. A simplified one-dimensional transport model for dual anions was developed and found to reliably describe the dynamic process of removal of both fluoride and chloride ions in CDI cells over a range of well-defined operating conditions. Based on the ability of the model to describe fluoride removal, it was extended to description of nitrate removal from brackish groundwaters and also found to perform well. Thus, the approach to description of ion removal, at least in batch studies, appears robust and should assist in optimization of design and operating conditions such that optimal removal of trace ionic species is achieved even when high background concentrations of salt are present.

Heterogenous Iron Oxide Assemblages for Use in Catalytic Ozonation: Reactivity, Kinetics, and Reaction Mechanism

Publisher: American Chemical Society (ACS)

Date: 17-01-2023

DOI: 10.1021/ACS.EST.2C07319

Optimization of constant-current operation in membrane capacitive deionization (MCDI) using variable discharging operations

Publisher: Elsevier BV

Date: 10-2021

DOI: 10.1016/J.WATRES.2021.117646

Influence of Dissolved Silicate on Rates of Fe(II) Oxidation

Publisher: American Chemical Society (ACS)

Date: 18-10-2016

DOI: 10.1021/ACS.EST.6B03015

Abstract: Increasing concentrations of dissolved silicate progressively retard Fe(II) oxidation kinetics in the circum-neutral pH range 6.0-7.0. As Si:Fe molar ratios increase from 0 to 2, the primary Fe(III) oxidation product transitions from lepidocrocite to a ferrihydrite/silica-ferrihydrite composite. Empirical results, supported by chemical kinetic modeling, indicated that the decreased heterogeneous oxidation rate was not due to differences in absolute Fe(II) sorption between the two solids types or competition for adsorption sites in the presence of silicate. Rather, competitive desorption experiments suggest Fe(II) was associated with more weakly bound, outer-sphere complexes on silica-ferrihydrite compared to lepidocrocite. A reduction in extent of inner-sphere Fe(II) complexation on silica-ferrihydrite confers a decreased ability for Fe(II) to undergo surface-induced hydrolysis via electronic configuration alterations, thereby inhibiting the heterogeneous Fe(II) oxidation mechanism. Water s les from a legacy radioactive waste site (Little Forest, Australia) were shown to exhibit a similar pattern of Fe(II) oxidation retardation derived from elevated silicate concentrations. These findings have important implications for contaminant migration at this site as well as a variety of other groundwater/high silicate containing natural and engineered sites that might undergo iron redox fluctuations.

Quantitative determination of trace hydrogen peroxide in the presence of sulfide using the Amplex Red/horseradish peroxidase assay

Publisher: Elsevier BV

Date: 04-2017

DOI: 10.1016/J.ACA.2017.02.033

Abstract: The Amplex Red/horseradish peroxidase (AR/HRP) assay for H

Importance of Iron Complexation for Fenton-Mediated Hydroxyl Radical Production at Circumneutral pH

Publisher: Frontiers Media SA

Date: 04-08-2016

DOI: 10.3389/FMARS.2016.00134

Electrochemically Generated cis-Carboxylato-Coordinated Iron(IV) Oxo Acid–Base Congeners as Promiscuous Oxidants of Water Pollutants

Publisher: American Chemical Society (ACS)

Date: 17-10-2017

DOI: 10.1021/ACS.INORGCHEM.7B02208

Abstract: The nonheme iron(IV) oxo complex [Fe

Short-Circuited Closed-Cycle Operation of Flow-Electrode CDI for Brackish Water Softening

Publisher: American Chemical Society (ACS)

Date: 27-07-2018

DOI: 10.1021/ACS.EST.8B02807

Abstract: While flow-electrode capacitive deionization (FCDI) is an emerging desalination technology, reduction in water hardness using this technology has so far received minimal attention. In this study, treatment of influents containing both monovalent and alent cations using FCDI was carried out with flow-electrodes operated in short-circuited closed-cycle (SCC) configuration. Divalent Ca

Cleaning strategies for iron-fouled membranes from submerged membrane bioreactor treatment of wastewaters

Publisher: Elsevier BV

Date: 02-2015

DOI: 10.1016/J.MEMSCI.2014.09.003

Leveraging coordination chemistry in the design of bipolar energy storage materials for redox flow batteries

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D1SE01966J

Abstract: A new cobalt( ii ) coordination complex, with two widely separated cobalt-centred redox processes, has been prepared and investigated as an energy storage material for bipolar redox flow batteries.

Use of fourier transform infrared spectroscopy to examine the Fe(II)-Catalyzed transformation of ferrihydrite

Publisher: Elsevier BV

Date: 12-2017

DOI: 10.1016/J.TALANTA.2017.07.018

Abstract: The Fe(II)-catalyzed transformation of the poorly crystalline Fe(III) oxyhydroxide mineral, ferrihydrite (Fh), to more crystalline Fe(III) mineral species such as magnetite, goethite, and lepidocrocite has been quantitatively evaluated under various conditions using X-ray adsorption spectroscopy (XAS) and Fourier transform infrared (FTIR) spectroscopy. Using the peak height of signature FTIR peaks of sub-micron sized lepidocrocite and goethite references minerals, the FTIR results were comparable to the XAS results within experimental error. This was independent of whether the Fe(II)-catalyzed transformation was initiated by the Fe(III)-reducing bacterium Shewanella oneidensis MR-1 or by added ferrous ammonium sulfate in the presence or absence of lactate. Whilst the use of FTIR has not been previously employed to follow this transformation process, it has advantages relative to XAS including a lower s le requirement (approximately 30-fold lower), greater accessibility and greater safety of operation. Whilst problems with quantifying magnetite in the presence of lepidocrocite were identified in this study using reference Fe(III) oxyhydroxide suspensions, large amounts of magnetite were not produced during transformation under the conditions employed in this study. Reference spectra of lath-like nano-goethite particles (with dimensions of approx. 10 × 50nm) also resulted in higher IR absorbance and a slight red-shift in signature peak positions relative to sub-micron sized goethite particles with this shift potentially affecting the reliable quantification of s les of unknown size. Despite this, good agreement between the XAS and FTIR data for s les containing iron oxides undergoing continuous transformation was obtained suggesting that FTIR may be a convenient, inexpensive means of following such mineral transformations.

Active chlorine mediated ammonia oxidation revisited: Reaction mechanism, kinetic modelling and implications

Publisher: Elsevier BV

Date: 11-2018

DOI: 10.1016/J.WATRES.2018.08.025

Abstract: Ammonia nitrogen removal from wastewaters has gained much attention in recent decades as a result of the environmental problems associated with discharge of excessive amounts of this critical nutrient including eutrophication of receiving waters, generation of offensive odours as a result of organism decay and complications associated with the disinfection of water supplies. While removal via biological processes represents the principal means by which a reduction in dissolved nitrogen concentrations is achieved, an electrochemical advanced oxidation process has been proposed as a potentially effective alternate means of removing ammonia from wastewaters with the removal associated with the in situ generation of oxidants (particularly active chlorine) at the anode. Here we describe the influence of key factors on the rate and extent of ammonia nitrogen removal in an electrochemical cell with a Ti/IrO

Opportunities for nanotechnology to enhance electrochemical treatment of pollutants in potable water and industrial wastewater – a perspective

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0EN00194E

Abstract: An international workshop identified how pore structures and unique properties that emerge at nano- to sub-nano- size domains can improve the energy efficiency and selectivity of electroseparation or electrocatalytic processes for treating water.

Coal chemical industry membrane concentrates: characterisation and treatment by ozonation and catalytic ozonation processes

Publisher: CSIRO Publishing

Date: 08-08-2022

DOI: 10.1071/EN22042

Abstract: Environmental context Reverse osmosis (RO) is widely used for the treatment of hazardous wastewaters produced from the coal chemical industry (CCI) to achieve zero liquid discharge however the use of RO inevitably results in accumulation of refractory organic matter in the RO membrane concentrate, the treatment of which is challenging. This work provides useful insights into the organic composition of RO concentrates obtained from a range of real CCI wastewaters. The efficacy of treatment of these concentrates by ozonation processes is assessed as is the cost effectiveness of such treatment. Rationale The enactment of increasingly stringent regulations has prompted the implementation of membrane technologies such as reverse osmosis (RO) in the management of coal chemical industry (CCI) wastewaters with the goal of achieving zero liquid discharge (ZLD). However, this practice inevitably results in the production of high salinity concentrates containing refractory organic matter. Methodology In this study, we characterised the organic composition of RO concentrates obtained from the CCI using a variety of methods including liquid chromatography–organic carbon/nitrogen detection (LC-OCND) and investigated the degradability of organic compounds present in these concentrates by ozonation and catalytic ozonation processes. Results and discussion Organic analysis using LC-OCND revealed that humic-like substances and low molecular weight neutral compounds were the dominant constituents in the CCI concentrates examined. Measurement of degradability of the CCI concentrate by a pure ozonation process showed low treatment efficiency (~20% dissolved organic carbon (DOC) removal) as a result of the refractory nature of the organic compounds present in the wastewater. The degradation of these organics by a catalytic ozonation process employing a commercially available Fe-oxide based catalyst was higher than that observed by pure ozonation although the extent of organics removal (DOC removal ~47%) is still low due to the refractory nature of the organics as well as the influence of salts on the catalyst performance. Techno-economic analysis of the pure ozonation and catalytic ozonation processes indicated that the total cost of implementation of the ozonation processes (homogeneous or heterogeneous) for CCI concentrate treatment is negligible compared with the overall cost of the complete ZLD process.

Electrochemical Reduction of Nitrate with Simultaneous Ammonia Recovery Using a Flow Cathode Reactor

Publisher: American Chemical Society (ACS)

Date: 17-11-2022

DOI: 10.1021/ACS.EST.2C06033

Abstract: The presence of excessive concentrations of nitrate in industrial wastewaters, agricultural runoff, and some groundwaters constitutes a serious issue for both environmental and human health. As a result, there is considerable interest in the possibility of converting nitrate to the valuable product ammonia by electrochemical means. In this work, we demonstrate the efficacy of a novel flow cathode system coupled with ammonia stripping for effective nitrate removal and ammonia generation and recovery. A copper-loaded activated carbon slurry (Cu@AC), made by a simple, low-cost wet impregnation method, is used as the flow cathode in this novel electrochemical reactor. Use of a 3 wt % Cu@AC suspension at an applied current density of 20 mA cm

Ligand-promoted reductive cleaning of iron-fouled membranes from submerged membrane bioreactors

Publisher: Elsevier BV

Date: 2018

DOI: 10.1016/J.MEMSCI.2017.09.059

Biogeochemical Mobility of Contaminants from a Replica Radioactive Waste Trench in Response to Rainfall-Induced Redox Oscillations

Publisher: American Chemical Society (ACS)

Date: 10-06-2021

DOI: 10.1021/ACS.EST.1C01604

Fodinomyces uranophilus gen. nov. sp. nov. and Coniochaeta fodinicola sp. nov., two uranium mine-inhabiting Ascomycota fungi from northern Australia

Publisher: Informa UK Limited

Date: 11-2014

DOI: 10.3852/14-013

Abstract: Seven acidophilic/acidotolerant fungal strains were characterized from s les of process waters (raffinate) at one of Australia's largest uranium mines, the Ranger Mine in Northern Territory. They were isolated from raffinate, which typically were very acidic (pH 1.7-1.8) and contained high concentrations of total dissolved/colloidal salts (> 100 g/L). Five of the isolates correspond to two new acidotolerant Ascomycota fungi. The first is a member of a new genus, here described as Fodinomyces (Teratosphaeriaceae, Capnodiales, Dothideomycetes) and does not show clear close affiliation with any other described fungus in the scientific literature. The second belongs to the genus Coniochaeta (Coniochaetaceae, Coniochaetales, Sordariomycetes) and is closely related to Coniochaeta hansenii.

Comparative proteomics of the toxigenic diazotroph Raphidiopsis raciborskii (cyanobacteria) in response to iron

Publisher: Wiley

Date: 30-11-2020

DOI: 10.1111/1462-2920.15328

Abstract: Raphidiopsis raciborskii is an invasive bloom‐forming cyanobacteria with the flexibility to utilize atmospheric and fixed nitrogen. Since nitrogen‐fixation has a high requirement for iron as an ezyme cofactor, we hypothesize that iron availability would determine the success of the species under nitrogen‐fixing conditions. This study compares the proteomic response of cylindrospermopsin‐producing and non‐toxic strains of R. racibroskii to reduced iron concentrations, under nitrogen‐fixing conditions, to examine any strain‐specific adaptations that might increase fitness under these conditions. We also compared their proteomic responses at exponential and stationary growth phases to capture the changes throughout the growth cycle. Overall, the toxic strain was more competitive under Fe‐starved conditions during exponential phase, with upregulated growth and transport‐related proteins. The non‐toxic strain showed reduced protein expression across multiple primary metabolism pathways. We propose that the increased expression of porin proteins during the exponential growth phase enables toxic strains to persist under Fe‐starved conditions with this ability providing a potential explanation for the increased fitness of cylindrospermoipsin‐producing strains during unfavourable environmental conditions.

Wasteforms for waste from advanced reprocessing

Publisher: Springer Science and Business Media LLC

Date: 12-2016

DOI: 10.1557/ADV.2017.217

Light-Induced Extracellular Electron Transport by the Marine Raphidophyte Chattonella marina

Publisher: American Chemical Society (ACS)

Date: 23-01-2015

DOI: 10.1021/ES503511M

Abstract: There is increasing interest in extracellular electron transfer (EET) from organisms to receptors, particularly in anaerobic biofilms at mineral surfaces. Less attention has been given to EET by planktonic organisms in oxic environments where extracellular electron generation and transport might be expected to be of limited consequence. In this study, the EET activity of the photosynthetic marine raphidophyte, Chattonella marina, was examined using a mediatorless photosynthetic microbial fuel cell with results showing positive light response. Electron output by organisms present in cell suspension was substantially higher than those present in biofilms at the electrode surface. Indeed, current generation under light illumination of the C. marina suspension continued even when contact between the organisms and the electrodes was prevented by dialysis membrane, suggesting that soluble electron carriers secreted by C. marina were facilitating the EET process. Cyclic voltammetry measurements of the cell-free exudate showed redox peaks in the range of 0.1-0.5 V (vs Ag/AgCl), confirming that redox active species were present in the cell suspension. Facilitation of electron transfer from the planktonic organism to the anode by endogenous redox-active exudates appears to be critical to current generation. The ability of these exudates to remain in their reduced state in the presence of oxygen is possibly a function of the spin-restricted nature of oxygen-mediated exudate oxidation. Quantification of the EET processes operating in this planktonic system assists in understanding the means and extent to which C. marina induces redox transformations in the external medium with these transformations presumably of benefit to the survival of this organism, potentially including facilitation of iron uptake and induction of toxicity to other organisms.

Mechanistic Insights into Free Chlorine and Reactive Oxygen Species Production on Irradiation of Semiconducting Silver Chloride Particles

Publisher: American Chemical Society (ACS)

Date: 07-11-2014

DOI: 10.1021/JP5068878

Flow-Electrode CDI Removes the Uncharged Ca–UO₂–CO₃ Ternary Complex from Brackish Potable Groundwater: Complex Dissociation, Transport, and Sorption

Publisher: American Chemical Society (ACS)

Date: 13-02-2019

DOI: 10.1021/ACS.EST.8B07157

Abstract: Unacceptably high uranium concentrations in decentralized and remote potable groundwater resources, especially those of high hardness (e.g ., high Ca

Depassivation of Aged Fe-0 by Divalent Cations: Correlation between Contaminant Degradation and Surface Complexation Constants

Publisher: American Chemical Society (ACS)

Date: 20-11-2014

DOI: 10.1021/ES503777A

Abstract: The dechlorination of trichloroethylene (TCE) by aged Fe(0) in the presence of a series of alent cations was investigated with the result that while no significant degradation of TCE was observed in Milli-Q water or in solutions of Ba(2+), Sr(2+), or Ca(2+), very effective TCE removal was observed in solutions containing Mg(2+), Mn(2+), Co(2+), Fe(2+), Ni(2+), Zn(2+), Cu(2+), or Pb(2+). The rate constants of TCE removal in the presence of particular cations were positively correlated to the log K representing the affinity of the cations for hydrous ferric oxide (HFO) surface sites though the treatments with Co(2+) and Ni(2+) were found to provide particularly strong enhancement in TCE degradation rate. The extent of Fe(II) release to solution also increased with increase in log K, while the solution pH from both experimental measurement and thermodynamic calculation decreased with increasing log K. While the peak areas of Fe and O XPS spectra of the passivated ZVI in the presence of Ba(2+), Sr(2+), and Ca(2+) were very close to those in Milli-Q water, very significant increases in surface Fe and O (and OH) were observed in solutions of Mg(2+), Mn(2+), Co(2+), Fe(2+), Ni(2+), Zn(2+), Cu(2+) and Pb(2+), revealing that the surface oxide layer dissolution is consistent with the recovery of aged Fe(0) with respect to TCE degradation. The depassivation process is proposed to involve (i) surface complexation of cations on surface coatings of aged Fe(0), (ii) dissolution of the hydrated surface as a consequence of magnetite exposure, and (iii) transport of electrons from underlying Fe(0) via magnetite to TCE, resulting in TCE dechlorination and, for some cations (Co(2+), Ni(2+), Cu(2+), and Pb(2+)), reduction to their zero or +1 valence state (with potential for these reduced metals to enhance TCE degradation).

Enhanced Direct Electron Transfer Mediated Contaminant Degradation by Fe(IV) Using a Carbon Black-Supported Fe(III)-TAML Suspension Electrode System

Publisher: American Chemical Society (ACS)

Date: 02-2023

DOI: 10.1021/ACS.EST.2C08467

Physiological and Proteomic Responses of Continuous Cultures of Microcystis aeruginosa PCC 7806 to Changes in Iron Bioavailability and Growth Rate

Publisher: American Society for Microbiology

Date: 10-2016

DOI: 10.1128/AEM.01207-16

Abstract: The hepatotoxin microcystin (MCYST) is produced by a variety of freshwater cyanobacterial species, including Microcystis aeruginosa . Interestingly, MCYST-producing M. aeruginosa strains have been shown to outcompete their nontoxic counterparts under iron-limiting conditions. However, the reasons for this are unclear. Here we examined the proteomic response of M. aeruginosa PCC 7806 continuous cultures under different iron and growth regimes. Iron limitation was correlated with a global reduction in levels of proteins associated with energy metabolism and photosynthesis. These proteomic changes were consistent with physiological observations, including reduced chlorophyll a content and reduced cell size. While levels of MCYST biosynthesis proteins did not fluctuate during the study period, both intra- and extracellular toxin quotas were significantly higher under iron-limiting conditions. Our results support the hypothesis that intracellular MCYST plays a role in protecting the cell against oxidative stress. Further, we propose that extracellular MCYST may act as a signaling molecule, stimulating MCYST production under conditions of iron limitation and enhancing the fitness of bloom populations. IMPORTANCE Microcystin production in water supply reservoirs is a global public health problem. Understanding the ecophysiology of hepatotoxic cyanobacteria, including their responses to the presence of key micronutrient metals such as iron, is central to managing harmful blooms. To our knowledge, this was the first study to examine proteomic and physiological changes occurring in M. aeruginosa continuous cultures under conditions of iron limitation at different growth rates.

Machine learning modelling of a membrane capacitive deionization (MCDI) system for prediction of long-term system performance and optimization of process control parameters in remote brackish water desalination

Publisher: Elsevier BV

Date: 12-2022

DOI: 10.1016/J.WATRES.2022.119349

Abstract: Membrane Capacitive Deionization (MCDI) is a promising electrochemical technique for water desalination. Previous studies have confirrmed the effectiveness of MCDI in removing contaminants from brackish groundwaters, especially in remote areas where electricity is scarce. However, as with other water treatment technologies, performance deterioration of the MCDI system still occurs, hindering the stability of long-term operation. Herein, a machine learning (ML) modelling framework and various ML models were developed to (i) investigate the performance deterioration due particularly to insufficient charging/discharging of the electrode caused by accumulation of ions and electrode scaling and (ii) optimise MCDI operating parameters such that the impacts of these deleterious effects on unit performance were minimized. The ML models developed in this work exhibited a prediction accuracy of cycle time with average mean absolute percentage error (MAPE) values of 16.82% and 16.09% after 30-fold cross validation for Random Forest (RF) and Multilayer Perceptron (MLP) models respectively. The pre-trained ML model predicted different declining trends of water production for two different operating conditions and provided corresponding recommendations on frequencies of chemical cleaning. A case study on the adjustment of operating parameters using the results suggested by the optimization ML model was conducted. The model validation results showed that the overall water production and water recovery of the system using the cycle-based optimized process control parameters (SCN 1) exceeds the MCDI system performance under three fixed parameter settings that were used at each stage of SCN 1 by 1.78% to 4.48% and 2.95% to 9.46%, respectively. Permutation-based and Shapley additive explanation (SHAP) coefficients were also employed for variable importance (VIMP) analysis to uncover the "black-box" nature of the ML models and to better understand the various features' contributions to overall MCDI system performance.

Direct electron transfer (DET) processes in a flow anode system–Energy-efficient electrochemical oxidation of phenol

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.WATRES.2021.117547

Elucidation of the interplay between Fe(II), Fe(III), and dopamine with relevance to iron solubilization and reactive oxygen species generation by catecholamines

Publisher: Wiley

Date: 12-05-2016

DOI: 10.1111/JNC.13615

An Integrated Flow-electrode Capacitive Deionization and Microfiltration (FCDI/MF) System for Continuous and Energy-efficient Brackish Water Desalination

Publisher: American Chemical Society (ACS)

Date: 28-10-2019

DOI: 10.1021/ACS.EST.9B04436

Abstract: Flow-electrode capacitive deionization (FCDI) is an emerging electrochemically driven technology for brackish and/or sea water desalination with merits of large salt adsorption capacity, high flow efficiency, and easy electrode management. While FCDI holds promise for continuous operation, there are very few investigations with regard to the regeneration/reuse of flowable electrodes and the separation of brine from electrodes with these operation prerequisites for real nonintermittent water desalination. In this study, we propose a novel module design to achieve these critical steps involving integration of an FCDI cell and a ceramic microfiltration (MF) contactor. Our investigations reveal that the brine discharge rate is the dominant factor for stable and efficient operation of the integrated module. Results obtained show that the integrated FCDI/MF system can be used to successfully separate brackish water (of salinities 1, 2 and 5 g L

Response of microbial community function to fluctuating geochemical conditions within a legacy radioactive waste trench environment

Publisher: Cold Spring Harbor Laboratory

Date: 28-03-2017

DOI: 10.1101/121376

Abstract: During the 1960s, small quantities of radioactive materials were co-disposed with chemical waste at the Little Forest Legacy Site (Sydney, Australia) in three-metre-deep, unlined trenches. Chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a six-week period immediately after a prolonged rainfall event to assess how changing water levels impact upon the microbial ecology and contaminant mobility. Collectively, results demonstrated that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solid-iron-associated species immediately after the initial rainwater pulse, to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the potentially important role that the taxonomically- erse microbial community played in this transition. In particular, aerobes dominated in the first day followed by an increase of facultative anaerobes/denitrifiers at day four. Towards the mid-end of the s ling period, the functional and taxonomic profiles depicted an anaerobic community distinguished by a higher representation of dissimilatory sulfate reduction and methanogenesis pathways. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs. The role of chemical and microbiological factors in mediating the biogeochemistry of groundwaters from trenches used to dispose of radioactive materials during the 1960s is examined in this study. Specifically, chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a six-week period immediately after a prolonged rainfall event to assess how changing water levels influence microbial ecology and contaminant mobility. Results demonstrate that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solidiron-associated species immediately after the initial rainwater pulse, to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the important role that the taxonomically- erse microbial community played in this transition. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs.

Optimization of sulfate removal from brackish water by membrane capacitive deionization (MCDI)

Publisher: Elsevier BV

Date: 09-2017

DOI: 10.1016/J.WATRES.2017.05.046

Abstract: Removal of sulfate from water is an environmental challenge faced by many industrial sectors as most existing options are inefficient, costly or unsustainable. The situation is further complicated by the typical coexistence of other ions. In this work, the feasibility of sulfate removal from brackish water by single-pass constant-current membrane capacitive deionization (MCDI) under reverse-current desorption was investigated. Results revealed that sulfate is preferentially removed from the aqueous solution by MCDI compared to chloride. Equivalent circuits of the MCDI system during adsorption and desorption were proposed and the dynamic variation of cell voltage and charging voltage at different adsorption currents was satisfactorily elucidated. Optimization studies were conducted with attention given to discussing the effects of four operating parameters, i.e., adsorption current, pump flow rate, ending cell voltage and desorption current, on three performance indicators (i.e., water recovery, energy consumption and sorption ratio of sulfate to chloride) on the premise of maintaining the effluent sulfate concentration below the specified threshold of 300 mg L

Effect of the Presence of Carbon in Ti₄O₇ Electrodes on Anodic Oxidation of Contaminants

Publisher: American Chemical Society (ACS)

Date: 23-03-2020

DOI: 10.1021/ACS.EST.9B07398

Fluoride Removal from Brackish Groundwaters by Constant Current Capacitive Deionization (CDI)

Publisher: American Chemical Society (ACS)

Date: 23-09-2016

DOI: 10.1021/ACS.EST.6B03307

Abstract: Charging capacitive deionization (CDI) at constant voltage (CV) produces an effluent stream in which ion concentrations vary with time. Compared to CV, charging CDI at constant current (CC) has several advantages, particularly a stable and adjustable effluent ion concentration. In this work, the feasibility of removing fluoride from brackish groundwaters by single-pass constant-current (SPCC) CDI in both zero-volt and reverse-current desorption modes was investigated and a model developed to describe the selective electrosorption of fluoride and chloride. It was found that chloride is preferentially removed from the bulk solution during charging. Both experimental and theoretical results are presented showing effects of operating parameters, including adsorption/desorption current, pump flow rate and fluoride/chloride feed concentrations, on the effluent fluoride concentration, average fluoride adsorption rate and water recovery. Effects of design parameters are also discussed using the validated model. Finally, we describe a possible CDI assembly in which, under appropriate conditions, fluoride water quality targets can be met. The model developed here adequately describes the experimental results obtained and shows how change in the selected system design and operating conditions may impact treated water quality.

Fluid Structure Interaction analysis of lateral fibre movement in submerged membrane reactors

Publisher: Elsevier BV

Date: 04-2016

DOI: 10.1016/J.MEMSCI.2015.12.056

Oxidative Dissolution of Silver Nanoparticles by Chlorine: Implications to Silver Nanoparticle Fate and Toxicity

Publisher: American Chemical Society (ACS)

Date: 25-03-2016

DOI: 10.1021/ACS.EST.6B00037

Abstract: The kinetics of oxidative dissolution of silver nanoparticles (AgNPs) by chlorine is investigated in this work, with results showing that AgNPs are oxidized in the presence of chlorine at a much faster rate than observed in the presence of dioxygen and/or hydrogen peroxide. The oxidation of AgNPs by chlorine occurs in air-saturated solution in stoichiometric amounts with 2 mol of AgNPs oxidized for each mole of chlorine added. Dioxygen plays an important role in OCl(-)-mediated AgNP oxidation, especially at lower OCl(-) concentrations, with the mechanism shifting from stoichiometric oxidation of AgNPs by OCl(-) in the presence of dioxygen to catalytic removal of OCl(-) by AgNPs in the absence of dioxygen. These results suggest that the presence of chlorine will mitigate AgNP toxicity by forming less-reactive AgCl(s) following AgNP oxidation, although the disinfection efficiency of OCl(-) may not be significantly impacted by the presence of AgNPs because a chlorine-containing species is formed on OCl(-) decay that has significant oxidizing capacity. Our results further suggest that the antibacterial efficacy of nanosilver particles embedded on fabrics may be negated when treated with detergents containing strong oxidants, such as chlorine.

Specific global responses to N and Fe nutrition in toxic and non-toxic Microcystis aeruginosa

Publisher: Wiley

Date: 04-08-2016

DOI: 10.1111/1462-2920.12958

Abstract: The bloom-forming cyanobacteria species Microcystis aeruginosa includes toxic and non-toxic (microcystin-producing) strains. Certain stress conditions stimulate synthesis of microcystin (MCYST) and enhance the binding of the MCYST molecule to proteins. In this quantitative proteomic study, we compared the response of a wild-type toxic strain PCC 7806, an mcyH(-) knockout non-toxic strain, and a naturally occurring non-toxic strain, PCC 7005, after 8 days in low iron (Fe) and nitrogen (N) starvation in order to assess the benefit of MCYST synthesis in non-optimal conditions. Fe limitation increased MCYST synthesis and caused an accumulation of phycobilisome proteins and the ferric iron transporter FutA only in the toxic PCC 7806 but not the non-toxic strains. In N starvation, photosynthetic, C and N metabolism proteins were more abundant in the non-toxic strains, as were chaperones and proteases. Significant interaction between nutrient availability and toxicity existed for thioredoxin peroxidase and several thioredoxin-regulated proteins. We propose a competition of MCYST for binding sites in thioredoxin-regulated proteins during oxidative stress (low Fe) but not in growth-limiting conditions (low N). This then leads to differences in the regulation of C:N metabolism in toxic and non-toxic M. aeruginosa in nutrient-replete and nutrient-limited conditions.

Cost-effective Chlorella biomass production from dilute wastewater using a novel photosynthetic microbial fuel cell (PMFC)

Publisher: Elsevier BV

Date: 2017

DOI: 10.1016/J.WATRES.2016.11.016

Abstract: While microalgae have been suggested as a promising substitute to conventional fossil fuels, their cost effective cultivation and harvesting constitutes a major challenge. In the work described here, a novel photosynthetic microbial fuel cell (PMFC) in which a stainless steel mesh with biofilm formed on it serves as both the cathode and filtration material has been developed. Results of this study reveal that, in addition to inducing oxygen reduction reactions under illumination, the biocathode is effective in preventing the washout of algae during continuous operation, resulting in retained biomass concentrations reaching 3.5-6.5 g L

Development of Redox-Active Flow Electrodes for High-Performance Capacitive Deionization

Publisher: American Chemical Society (ACS)

Date: 30-11-2016

DOI: 10.1021/ACS.EST.6B03424

Abstract: An innovative flow electrode comprising redox-active quinones to enhance the effectiveness of water desalination using flow-electrode capacitive deionization (FCDI) is described in this study. The results show that, in addition to carbon particle contact, the presence of the aqueous hydroquinone (H

Linkage Projects - Grant ID: LP0455697

Start Date: 2004

End Date: 06-2009

Amount: $407,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0665515

Start Date: 04-2006

End Date: 11-2009

Amount: $310,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0561150

Start Date: 2005

End Date: 06-2009

Amount: $150,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP120103222

Start Date: 04-2012

End Date: 12-2016

Amount: $360,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0987188

Start Date: 08-2009

End Date: 07-2012

Amount: $285,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0210903

Start Date: 2002

End Date: 06-2005

Amount: $202,118.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0558710

Start Date: 2005

End Date: 06-2008

Amount: $402,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP100200792

Start Date: 12-2010

End Date: 01-2015

Amount: $300,000.00

Funder: Australian Research Council

Linkage - International - Grant ID: LX0346800

Start Date: 2003

End Date: 01-2004

Amount: $71,299.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0883561

Start Date: 01-2009

End Date: 01-2012

Amount: $180,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP210103727

Start Date: 2021

End Date: 12-2023

Amount: $400,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0347117

Start Date: 06-2003

End Date: 12-2009

Amount: $147,198.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP190103375

Start Date: 2019

End Date: 12-2021

Amount: $390,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE120100162

Start Date: 01-2012

End Date: 12-2016

Amount: $150,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0882388

Start Date: 2008

End Date: 12-2008

Amount: $130,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP100100056

Start Date: 07-2010

End Date: 03-2014

Amount: $548,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP130101107

Start Date: 02-2014

End Date: 01-2017

Amount: $395,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP170101180

Start Date: 07-2019

End Date: 06-2022

Amount: $498,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP220200912

Start Date: 09-2023

End Date: 09-2026

Amount: $612,689.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP150102248

Start Date: 06-2015

End Date: 06-2019

Amount: $514,700.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0880298

Start Date: 2008

End Date: 12-2011

Amount: $298,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP180101146

Start Date: 12-2019

End Date: 02-2023

Amount: $459,000.00

Funder: Australian Research Council

Special Research Initiatives - Grant ID: SR0354511

Start Date: 12-2003

End Date: 12-2004

Amount: $10,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP170103512

Start Date: 2017

End Date: 12-2019

Amount: $335,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0668316

Start Date: 2006

End Date: 12-2012

Amount: $345,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP120103234

Start Date: 07-2012

End Date: 12-2016

Amount: $450,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989680

Start Date: 2009

End Date: 12-2009

Amount: $300,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0346392

Start Date: 02-2003

End Date: 08-2006

Amount: $319,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP150100854

Start Date: 04-2016

End Date: 12-2019

Amount: $560,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE180100073

Start Date: 03-2018

End Date: 12-2019

Amount: $468,474.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE110100174

Start Date: 12-2011

End Date: 12-2012

Amount: $800,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989759

Start Date: 2009

End Date: 12-2010

Amount: $360,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0883080

Start Date: 2008

End Date: 12-2008

Amount: $490,000.00

Funder: Australian Research Council

Special Research Initiatives - Grant ID: SR0354656

Start Date: 01-2004

End Date: 03-2005

Amount: $20,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP160101153

Start Date: 08-2016

End Date: 08-2020

Amount: $450,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0219352

Start Date: 2002

End Date: 12-2004

Amount: $302,570.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0348062

Start Date: 02-2004

End Date: 09-2007

Amount: $105,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0219475

Start Date: 10-2002

End Date: 12-2004

Amount: $354,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP100100852

Start Date: 2010

End Date: 09-2014

Amount: $599,662.00

Funder: Australian Research Council