ORCID Profile
0000-0003-4042-7589
Current Organisation
University of Canterbury
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Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 03-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RA04185C
Abstract: A multi-step chemical replication method using natural green leaves as templates can produce a porous, visible-light active TiO 2 -based photocatalyst.
Publisher: IEEE
Date: 2006
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.JHAZMAT.2019.121161
Abstract: Mesoporous ZSM-5 (MFI) zeolite was synthesized by using bacterial cellulose-derived activated carbon (BC-AC500) with a high surface area as a hard template. Different ratios of BC-AC500 and zeolite precursor gel were prepared in a Teflon-lined autoclave and crystallized at 180 °C for 48 h in a rotating oven. The physicochemical properties of the s les were characterized by x-ray diffraction (XRD), scanning/transmission electron microscopies (SEM/TEM), and N
Publisher: Elsevier BV
Date: 09-2018
Publisher: MDPI AG
Date: 06-10-2017
DOI: 10.3390/CATAL7100297
Publisher: MDPI AG
Date: 06-12-2021
DOI: 10.3390/EN14238167
Abstract: This study investigated the effect of HCl in biomass gasification producer gas on the CO2 capture efficiency and contaminants removal efficiency by CaO-Fe2O3 based sorbent material in the calcium looping process. Experiments were conducted in a fixed bed reactor to capture CO2 from the producer gas with the combined contaminants of HCl at 200 ppmv, H2S at 230 ppmv, and NH3 at 2300 ppmv. The results show that with presence of HCl in the feeding gas, sorbent reactivity for CO2 capture and contaminants removal was enhanced. The maximum CO2 capture was achieved at carbonation temperatures of 680 °C, with efficiencies of 93%, 92%, and 87%, respectively, for three carbonation-calcination cycles. At this carbonation temperature, the average contaminant removal efficiencies were 92.7% for HCl, 99% for NH3, and 94.7% for H2S. The outlet contaminant concentrations during the calcination process were also examined which is useful for CO2 reuse. The pore structure change of the used sorbent material suggests that the HCl in the feeding gas contributes to high CO2 capture efficiency and contaminants removal simultaneously.
Publisher: Springer Science and Business Media LLC
Date: 04-01-2021
Publisher: Springer Science and Business Media LLC
Date: 03-2016
DOI: 10.1007/S10653-016-9808-2
Abstract: Permeable reactive barriers (PRBs) have proved to be a promising passive treatment to control groundwater contamination and associated human health risks. This study explored the potential use of low-cost adsorbents as PRBs media and assessed their longevity and risk mitigation against leaching of acidic rainfall through an e-waste recycling site, of which Cu, Zn, and Pb were the major contaminants. Batch adsorption experiments suggested a higher adsorption capacity of inorganic industrial by-products [acid mine drainage sludge (AMDS) and coal fly ash (CFA)] and carbonaceous recycled products [food waste compost (FWC) and wood-derived biochar] compared to natural inorganic minerals (limestone and apatite). Continuous leaching tests of sand columns with 10 wt% low-cost adsorbents were then conducted to mimic the field situation of acidic rainfall infiltration through e-waste-contaminated soils (collected from Qingyuan, China) by using synthetic precipitation leaching procedure (SPLP) solution. In general, Zn leached out first, followed by Cu, and finally delayed breakthrough of Pb. In the worst-case scenario (e.g., at initial concentrations equal to 50-fold of average SPLP result), the columns with limestone, apatite, AMDS, or biochar were effective for a relatively short period of about 20-40 pore volumes of leaching, after which Cu breakthrough caused non-cancer risk concern and later-stage Pb leaching considerably increased both non-cancer and lifetime cancer risk associated with portable use of contaminated water. In contrast, the columns with CFA or FWC successfully mitigated overall risks to an acceptable level for a prolonged period of 100-200 pore volumes. Therefore, with proper selection of low-cost adsorbents (or their mixture), waste-based PRBs is a technically feasible and economically viable solution to mitigate human health risk due to contaminated groundwater at e-waste recycling sites.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 07-2019
Publisher: MDPI AG
Date: 17-03-2019
DOI: 10.3390/CATAL9030274
Abstract: Hierarchical zeolites have been extensively studied due to their enhancement of intra-crystalline diffusion, which leads to the improved catalytic activity and resistance to coking-deactivation. Traditional synthesis strategies of hierarchical zeolites via post-treatment or directing synthesis with the aid of mesoporous template are often characterized by high energy consumption and substantial use of expensive and environmentally unfriendly organic templates. In the recent decade, new green synthesis protocols have been developed for the effective synthesis of conventional and hierarchical zeolites. In this review, the latest advancements on the green synthesis of hierarchical zeolites are summarized and discussed in detail.
Publisher: Springer Science and Business Media LLC
Date: 17-01-2019
Publisher: American Chemical Society (ACS)
Date: 10-08-2009
DOI: 10.1021/IE900731S
Publisher: American Chemical Society (ACS)
Date: 07-05-2018
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.JENVMAN.2018.07.087
Abstract: Nanotechnology is currently one of the highest priority research fields in many countries due to its immense potentiality and economic impact. Nanotechnology involves the research, development, production, and processing of structures and materials on a nanometer scale in various fields of science, technology, health care, industries, and agriculture. As such, it has contributed to the gradual restructuring of many associated technologies. However, due to the uncertainties and irregularities in shape, size, and chemical compositions, the presence of certain nanomaterials may exert adverse impacts on the environment as well as human health. Concerns have thus been raised about the destiny, transport, and transformation of nanoparticles released into the environment. A critical evaluation of the current states of knowledge regarding the exposure and effects of nanomaterials on the environment and human health is discussed in this review. Recognition on the potential advantages and unintended dangers of nanomaterials to the environment and human health is critically important to pursue their development in the future.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8GC00358K
Abstract: Propylene carbonate and γ-valerolactone prevent transformation of Sn 4+ (aq) into inactive SnO 2(s) , maintaining active Lewis acidity for glucose-to-fructose isomerisation.
Publisher: Elsevier BV
Date: 03-2019
Publisher: American Chemical Society (ACS)
Date: 05-09-2022
Publisher: Wiley
Date: 07-12-2020
Publisher: Elsevier BV
Date: 03-2017
Publisher: American Chemical Society (ACS)
Date: 05-01-2022
Abstract: Biogas is an environmentally friendly and sustainable energy resource that can substitute or complement conventional fossil fuels. For practical uses, biogas upgrading, mainly through the effective separation of CO
Publisher: Elsevier BV
Date: 05-2022
Publisher: Springer Science and Business Media LLC
Date: 27-05-2014
DOI: 10.1007/S11356-014-3032-3
Abstract: In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation.
Publisher: Elsevier BV
Date: 11-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2GC36067E
Publisher: Elsevier BV
Date: 03-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA02462B
Abstract: An oriented, hydrophobic membrane made of a decadodecasil 3 rhombohedral (DDR) zeolite (0.36 nm) could separate CO 2 (0.33 nm) from larger N 2 (0.364 nm) reliably.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.CHEMOSPHERE.2019.04.004
Abstract: -While sulfate radical (SO
Publisher: Elsevier BV
Date: 09-2018
Publisher: American Chemical Society (ACS)
Date: 23-05-2014
DOI: 10.1021/JA5016298
Abstract: As a subset of the metal-organic frameworks, zeolitic imidazolate frameworks (ZIFs) have potential use in practical separations as a result of flexible yet reliable control over their pore sizes along with their chemical and thermal stabilities. Among many ZIF materials, we explored the effect of thermal treatments on the ZIF-7 structure, known for its promising characteristics toward H2 separations the pore sizes of ZIF-7 (0.29 nm) are desirable for molecular sieving, favoring H2 (0.289 nm) over CO2 (0.33 nm). Although thermogravimetric analysis indicated that ZIF-7 is thermally stabile up to ~400 °C, the structural transition of ZIF-7 to an intermediate phase (as indicated by X-ray analysis) was observed under air as guest molecules were removed. The transition was further continued at higher temperatures, eventually leading toward the zinc oxide phase. Three types of ZIF-7 with differing shapes and sizes (~100 nm spherical, ~400 nm rhombic-dodecahedral, and ~1300 nm rod-shaped) were employed to elucidate (1) thermal structural transitions while considering kinetically relevant processes and (2) discrepancies in the N2 physisorption and CO2 adsorption isotherms. The largest rod-shaped ZIF-7 particles showed a delayed thermal structural transition toward the stable zinc oxide phase. The CO2 adsorption behaviors of the three ZIF-7s, despite their identical crystal structures, suggested minute differences in the pore structures in particular, the smaller spherical ZIF-7 particles provided reversible CO2 adsorption isotherms at ~30-75 °C, a typical temperature range of flue gases from coal-fired power plants, in contrast to the larger rhombic-dodecahedral and rod-shaped ZIF-7 particles, which exhibited hysteretic CO2 adsorption/desorption behavior.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.JHAZMAT.2019.04.049
Abstract: CO
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.BIORTECH.2017.01.017
Abstract: This study aimed to maximize the valorization of bread waste, a typical food waste stream, into hydroxymethylfurfural (HMF) by improving our kinetic understanding. The highest HMF yield (30mol%) was achieved using SnCl
Publisher: Elsevier BV
Date: 06-2020
Publisher: American Chemical Society (ACS)
Date: 28-11-2011
DOI: 10.1021/IE201467U
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 10-2015
Publisher: American Chemical Society (ACS)
Date: 24-09-2018
Publisher: Elsevier BV
Date: 09-2003
Publisher: American Chemical Society (ACS)
Date: 06-04-2015
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.BIORTECH.2016.08.002
Abstract: This study aimed to transform food waste into a value-added chemical, hydroxymethylfurfural (HMF), and unravel the tangled effects induced by the metal catalysts on each single step of the successive conversion pathway. The results showed that using cooked rice and bread crust as surrogates of starch-rich food waste, yields of 8.1-9.5% HMF and 44.2-64.8% glucose were achieved over SnCl4 catalyst. Protons released from metal hydrolysis and acidic by-products rendered Brønsted acidity to catalyze fructose dehydration and hydrolysis of glycosidic bond. Lewis acid site of metals could facilitate both fructose dehydration and glucose isomerization via promoting the rate-limiting internal hydride shift, with the catalytic activity determined by its electronegativity, electron configuration, and charge density. Lewis acid site of a higher valence also enhanced hydrolysis of polysaccharide. However, the metals also catalyzed undesirable polymerization possibly by polarizing the carbonyl groups of sugars and derivatives, which should be minimized by process optimization.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Springer Science and Business Media LLC
Date: 14-01-2014
Publisher: Elsevier BV
Date: 03-2020
Publisher: Wiley
Date: 07-2023
Abstract: Utilizing renewable energy to hydrogenate carbon dioxide into fuels eliminates massive CO 2 emissions from the atmosphere and diminishes our need for using fossil fuels. This review presents the most recent developments for designing heterogeneous catalysts for the hydrogenation of CO 2 to formate, methanol, and C 2+ hydrocarbons. Thermodynamic challenges and mechanistic insights are discussed, providing a strong foundation to propose a suitable catalyst. The main body of this review focuses on nanostructured catalysts for constructing efficient heterogeneous systems. The most important factors affecting catalytic performance are highlighted, including active metals, supports and promoters that can potentially be used. The summary of the results and the outlook are presented in the final section. During the past few decades, heterogeneous CO 2 hydrogenation has gained much attention and made tremendous progress. Thus, many highly efficient catalysts have been studied to discover their active sites and provide mechanistic insights. This paper summarizes recent advances in CO 2 hydrogenation and its conversion into various hydrocarbons such as formate, methanol, and C 2+ products. As for formate production, Au and Ru nanocatalysts show superior activity. However, considering the catalyst cost, Cu‐based catalysts have an excellent prospect for methanol production, among other catalysts. Ultra‐small nanoparticles and nanoclusters appear promising to provide highly active cost‐effective catalysts. A growing number of researchers are investigating the possibility of directly synthesizing C 2+ products through CO 2 hydrogenation. The major challenge in producing heavy hydrocarbons is breaking the ASF limitations, which have been achieved over bifunctional catalysts using zeolites. Using suitable support and promoter can lead to a superior activity, ascribed to structural, electronic, and chemical promotional effects.
Publisher: Elsevier BV
Date: 12-2016
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.CHEMOSPHERE.2013.09.097
Abstract: Utilising locally available industrial by-products for in situ metal stabilisation presents a low-cost remediation approach for contaminated soil. This study explored the potential use of inorganic (acid mine drainage (AMD) sludge and zero-valent iron) and carbonaceous materials (green waste compost, manure compost, and lignite) for minimising the environmental risks of As and Cu at a timber treatment site. After 9-month soil incubation, significant sequestration of As and Cu in soil solution was accomplished by AMD sludge, on which adsorption and co-precipitation could take place. The efficacy of AMD sludge was comparable to that of zero-valent iron. There was marginal benefit of adding carbonaceous materials. However, in a moderately aggressive environment (Toxicity Characteristic Leaching Procedure), AMD sludge only suppressed the leachability of As but not Cu. Therefore, the provision of compost and lignite augmented the simultaneous reduction of Cu leachability, probably via surface complexation with oxygen-containing functional groups. Under continuous acid leaching in column experiments, combined application of AMD sludge with compost proved more effective than AMD sludge with lignite. This was possibly attributed to the larger amount of dissolved organic matter with aromatic moieties from lignite, which may enhance Cu and As mobility. Nevertheless, care should be taken to mitigate ecological impact associated with short-term substantial Ca release and continuous release of Al at a moderate level under acid leaching. This study also articulated the engineering implications and provided recommendations for field deployment, material processing, and assessment framework to ensure an environmentally sound application of reactive materials.
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 08-2016
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 03-2019
Publisher: American Chemical Society (ACS)
Date: 03-09-2021
Publisher: Elsevier BV
Date: 05-2016
Publisher: American Chemical Society (ACS)
Date: 12-02-2019
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 12-2023
Publisher: Informa UK Limited
Date: 21-12-2014
DOI: 10.1080/09593330.2014.992481
Abstract: There is an increasing interest to recycle greywater for meeting non-portable water demand. However, linear alkylbenzene sulphonates (a form of anionic surfactants) that are commonly found in greywater are less biodegradable at moderate to high concentrations. A fenton-like system is a relatively economic advanced oxidation process that can potentially be used for surfactant degradation in greywater treatment. This study investigated the feasibility of zerovalent iron (ZVI)-mediated Fenton's oxidation of sodium dodecylbenzene sulphonate (SDBS) using Fe0/H2O2 and Fe2+/Fe0/H2O2 systems under a range of operating conditions. For the Fe0/H2O2 binary system, the initial pH value and Fe0 dosage played important roles in final degradation efficiency. For the Fe2+/Fe0/H2O2 ternary systems, a small amount of Fe2+ (0.5-1.7 mM) contributed a synergistic effect to promote iron recycling and SDBS degradation. Approximately, 90% of SDBS mineralization efficiency was accomplished within 15 min at a pH range from 3.0 to 6.5, using 18 mM Fe0 and 15 mM H2O2. However, the removal kinetics was rate-limited by Fe2+ dissolution from the ZVI surfaces. The Fenton-like process of the Fe2+/Fe0/H2O2 ternary system also presents a promising treatment method for synthetic greywater, in which 90% TOC removal was achieved within the first 10 min 78% COD and 91% BOD5 were achieved after 120 min of reaction.
Publisher: American Chemical Society (ACS)
Date: 24-06-2016
Publisher: MDPI AG
Date: 31-01-2019
DOI: 10.3390/CATAL9020127
Abstract: Zeolites are promising catalysts that are widely used in petrochemical, oil, and gas industries due to their unique characteristics, such as ordered microporous networks, good hydrothermal stability, large surface area, tunable acidity, and shape-selectivity. Nevertheless, the sole presence of microporous channels in zeolites inevitably restricts the diffusion of bulky reactants and products into and out of the microporous networks, leading to retarded reaction rates or catalyst deactivation. This problem can be overcome by developing hierarchical zeolites which involve mesoporous and macroporous networks. The meso- and macro-porosities can enhance the mass transport of molecules and simultaneously maintain the intrinsic shape selectivity of zeolite microporosity. Hierarchical zeolites are mainly developed through post-synthesis and pre-synthesis or in situ modification of zeolites. In this review, we evaluated both pre-synthesis and post-synthesis modification strategies with more focus on post-synthesis modification strategies. The role of various synthesis strategies on the intrinsic properties of hierarchical zeolites is discussed. The catalytic performance of hierarchical zeolites in important biomass reactions, such as catalytic pyrolysis of biomass feedstock and upgradation of bio-oil, has been summarized. The utilization of hierarchical zeolites tends to give a higher aromatic yield than conventional zeolites with microporosity solely.
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.ENVRES.2019.03.046
Abstract: The adsorption characteristics of four aromatic hydrocarbons (i.e., benzene, toluene, xylene, and styrene) onto ground-activated carbon were investigated both independently and as a mixture of the four at <10 Pa partial pressures (e.g., 0-100 ppm concentration range). The maximum sorption capacities for benzene, toluene, styrene, and xylene were measured both as a sole component and as a mixture (at 10 Pa). In the former, the values were approximately 123, 184, 272, and 238 mg g
Publisher: Wiley
Date: 06-11-2020
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 05-2019
Publisher: American Chemical Society (ACS)
Date: 11-12-2018
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.CHEMOSPHERE.2017.06.095
Abstract: This study aimed to produce a high-value platform chemical, hydroxymethylfurfural (HMF), from food waste and evaluate the catalytic performance of trivalent and tetravalent metals such as AlCl
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 08-2019
Publisher: Walter de Gruyter GmbH
Date: 26-05-2020
Abstract: A monolithic catalytic support is potentially a thermally effective system for application in an intensified steam reforming process. In contrast to ceramic analogues, metal monoliths exhibit better mechanical strength, thermal conductivity and a thermal expansion coefficient equivalent to that of the reformer tube. A layer of carbon nanomaterials grown on the metal monolith’s surface can act as a textural promoter offering sufficient surface area for hosting homogeneously dispersed catalytically active metal particles. Carbon nanomaterials possess good thermal conductivities and mechanical properties. The future potential of this system in steam reforming is envisaged based on hypothetical speculation supported by fundamental carbon studies from as early as the 1970s, and sufficient literature evidence from relatively recent research on the use of monoliths and carbon in catalysis. Thermodynamics and active interaction between metal particle surface and carbon-containing gas have resulted in coke deposition on the nickel-based catalysts in steam reforming. The coke is removable through gasification by increasing the steam-to-carbon ratio to above stoichiometric but risks a parallel gasification of the carbon nanomaterials textural promoter, leading to nickel particle sintering. We present our perspective based on literature in which, under the same coke gasification conditions, the highly crystallised carbon nanomaterials maintain high chemical and thermal stability.
Location: United States of America
No related grants have been discovered for Alex Yip.