ORCID Profile
0000-0002-1056-5799
Current Organisation
Bangor University
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Publisher: Elsevier BV
Date: 05-2017
Publisher: Springer Science and Business Media LLC
Date: 04-2005
Publisher: Springer Science and Business Media LLC
Date: 11-2011
Publisher: Elsevier BV
Date: 2022
DOI: 10.2139/SSRN.4103257
Publisher: Informa UK Limited
Date: 25-09-2017
Publisher: Wiley
Date: 18-06-2020
DOI: 10.1002/JNR.24672
Publisher: Elsevier BV
Date: 2022
DOI: 10.2139/SSRN.4173950
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 07-2020
Publisher: Informa UK Limited
Date: 03-2013
Publisher: American Chemical Society (ACS)
Date: 04-03-2020
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 12-2012
Publisher: Elsevier BV
Date: 2022
DOI: 10.2139/SSRN.4116256
Publisher: Elsevier BV
Date: 02-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9TA12285K
Abstract: The first metallated hypercrosslinked polymers have been synthesised, characterised and found to have remarkable capacity for uptake of fluoride ions.
Publisher: MDPI AG
Date: 05-11-2021
DOI: 10.3390/ENG2040033
Abstract: The extraction of Cu from mixed-metal acidic solutions by the thiourea-functionalized resin Puromet MTS9140 was studied. Despite being originally manufactured for precious metal recovery, a high selectivity towards Cu was observed over other first-row transition metals ( % removal), highlighting a potential for this resin in base metal recovery circuits. Resin behaviour was characterised in batch-mode under a range of pH and sulphate concentrations and as a function of flow rate in a fixed-bed setup. In each instance, a high selectivity and capacity (max. 32.04 mg/g) towards Cu was observed and was unaffected by changes in solution chemistry. The mechanism of extraction was determined by XPS to be through reduction of Cu(II) to Cu(I) rather than chelation. Elution of Cu was achieved by the use of 0.5 M–1 M NaClO3. Despite effective Cu elution (82%), degradation of resin functionality was observed, and further detailed through the application of IC analysis to identify degradation by-products. This work is the first detailed study of a thiourea-functionalized resin being used to selectively target Cu from a complex multi-metal solution.
Publisher: Springer Science and Business Media LLC
Date: 10-02-2020
DOI: 10.1007/S12649-020-00954-1
Abstract: This work aims to contribute to addressing the global challenge of recycling and valorising spent potlining a hazardous solid waste product of the aluminium smelting industry. This has been achieved using a simple two-step chemical leaching treatment of the waste, using dilute lixiviants, namely NaOH, H 2 O 2 and H 2 SO 4 , and at ambient temperature. The potlining and resulting leachate were characterised by spectroscopy and microscopy to determine the success of the treatment, as well as the morphology and mineralogy of the solid waste. This confirmed that the potlining s les were a mixture of contaminated graphite and refractory materials, with high variability of composition. A large quantity of fluoride was solublised by the leaching process, as well as numerous metals, some of them toxic. The acidic and caustic leachates were combined and the aluminium and fluoride components were selectively extracted, using a modified ion-exchange resin, in fixed-bed column experiments. The resin performed above expectations, based on previous studies, which used a simulant feed, extracting fluoride efficiently from leachates of significantly different compositions. Finally, the fluoride and aluminium were coeluted from the column, using NaOH as the eluent, creating an enriched aqueous stream, relatively free from contaminants, from which recovery of synthetic cryolite can be attempted. Overall, the study accomplished several steps in the development of a fully-realised spent potlining treatment system.
Publisher: Frontiers Media SA
Date: 16-11-2018
Publisher: Elsevier BV
Date: 09-2017
Publisher: Springer Science and Business Media LLC
Date: 27-12-2012
Publisher: Springer Science and Business Media LLC
Date: 09-02-2022
Publisher: Academy of Science of South Africa
Date: 2008
Publisher: Springer Science and Business Media LLC
Date: 2020
DOI: 10.1007/S10953-019-00942-7
Abstract: In this report, the interaction of monoamide/diamide and monoamide/diglycolamide mixtures with $${\\text{UO}}_{2}^{2 + }$$ UO 2 2 + are investigated in pH = 1 methanolic nitric acid media. These monoamides include N , N -dimethylacetamide (DMAA), N , N -diethylacetamide (DEAA), N , N -dibutylacetamide (DBAA) and N , N -dibutylbutanamide (DBBA). N , N , N ′ N ′-tetraethylmalonamide (TEMA) and N , N , N ′, N ′-tetraethyldiglycolamide (TEDGA), which were chosen as model diamides and diglycolamides, respectively. Complex stability constants for each ligand were modelled using the Stability Quotients Using Absorbance Data program using UV–visible data. Complex stoichiometry of ligand mixtures was determined using Job plots and UV–Vis spectrometry. Monoamides were confirmed to produce only disolvate complexes with $${\\text{UO}}_{2}^{2 + }$$ UO 2 2 + in solution. The log 10 ( K ) values for monoamides were found to be independent of amine-side chain length, but were slightly dependent on the carbonyl-side chain length. TEDGA was found to produce multiple uranyl complexes in solution. Job plot data indicated that the uranyl cation strongly prefers to bond either only with the monoamide or diamide in ternary monoamide–diamide–UO 2 systems. Monoamide–diglycolamide–UO 2 systems were more complicated, with Job plot data indicating the potential for multiple ternary species being present is dependent on the monoamide structure.
Publisher: EDP Sciences
Date: 2016
DOI: 10.1051/EPJN/2016022
Publisher: Elsevier BV
Date: 07-2017
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 11-2020
Publisher: Japan Association of Ion Exchange
Date: 20-09-2018
DOI: 10.5182/JAIE.29.104
Publisher: Japan Association of Ion Exchange
Date: 20-09-2018
DOI: 10.5182/JAIE.29.53
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 06-2017
Publisher: Elsevier BV
Date: 08-2018
Publisher: Springer Science and Business Media LLC
Date: 13-04-2012
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 12-2022
DOI: 10.1016/J.JENVMAN.2022.116279
Abstract: Phosphate shortages and the ensuing pressures on food security have led to an interest in processed sewage sludge as a substitute for commercial fertilisers. The presence of heavy metals in this nutrient source causes concerns around environmental release and pollution. This work builds towards a resin-in-pulp sludge detoxification process. It showcases the kinetic and thermodynamic adsorption capabilities of the ion-exchange resins C107E (carboxylic acid functionality), MTS9301 (iminodiacetic acid) and TP214 (thiourea), with respect to Cu(II), Fe(II), Pb(II) and Zn(II), within a simulated sewage sludge weak acid (acetate) leachate. The isotherms produced in this complex system were quite different to those generated when single metals were investigated in isolation, with desorption of lower affinity species clearly observed at higher equilibrium concentration values. Mixed-metal isotherm data were fitted to common two-parameter isotherm models and also a novel modified Langmuir model, which better accounted for the effects of desorption and competition. Kinetic data were also fit to common two-parameter models results suggesting the system was likely film diffusion-controlled and followed pseudo-2nd-order kinetics. C107E displayed rapid adsorption of lead (t
Publisher: American Chemical Society
Date: 09-06-2006
Publisher: Springer Science and Business Media LLC
Date: 2012
Publisher: Elsevier BV
Date: 08-2011
Publisher: Wiley
Date: 21-11-2016
DOI: 10.1002/APP.44618
Publisher: MDPI AG
Date: 05-10-2020
DOI: 10.3390/MI11100923
Abstract: We introduce fluoride-selective anion exchange resin sorbents as sensitisers into membranes for water-gated field effect transistors (WGTFTs). Sorbents were prepared via metal (La or Al)-loading of a commercial macroporous aminophosphonic acid resin, PurometTM MTS9501, and were filled into a plasticised poly(vinyl chloride) (PVC) phase transfer membrane. We found a potentiometric response (membrane potential leading to WGTFT threshold shift) to fluoride following a Langmuir–Freundlich (LF) adsorption isotherm with saturated membrane potential up to ~480 mV, extremely low characteristic concentration c1/2 = 1/K, and picomolar limit of detection (LoD), even though ion exchange did not build up charge on the resin. La-loading gave a superior response compared to Al-loading. Membrane potential characteristics were distinctly different from charge accumulating sensitisers (e.g., organic macrocycles) but similar to the Cs+ (cation) selective ion-exchanging zeolite mineral ‘mordenite’. We propose a mechanism for the observed threshold shift and investigate interference from co-solutes. Strong interference from carbonate was brought under control by ‘diluting’ metal loading in the resin. This work sets a template for future studies using an entirely new ‘family’ of sensitisers in applications where very low limit of detection is essential such as for ions of arsenic, mercury, copper, palladium, and gold.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Frontiers Media SA
Date: 18-10-2022
DOI: 10.3389/FCHEM.2022.997147
Abstract: This paper is part of a growing body of research work looking at the synthesis of an optimal adsorbent for the capture and containment of aqueous radioiodine from nuclear fuel reprocessing waste. 32 metalated commercial ion exchange resins were subjected to a two-tier screening assessment for their capabilities in the uptake of iodide from aqueous solutions. The first stage determined that there was appreciable iodide capacity across the adsorbent range (12–220 mg·g −1 ). Candidates with loading capacities above 40 mg·g −1 were progressed to the second stage of testing, which was a fractional factorial experimental approach. The different adsorbents were treated as discrete variables and concentrations of iodide, co-contaminants and protons (pH) as continuous variables. This gave rise to a range of extreme conditions, which were representative of the industrial challenges of radioiodine abatement. Results were fitted to linear regression models, both for the whole dataset ( R 2 = 59%) and for in idual materials ( R 2 = 18–82%). The overall model determined that iodide concentration, nitrate concentration, pH and interactions between these factors had significant influences on the uptake. From these results, the top six materials were selected for project progression, with others discounted due to either poor uptake or noticeable iodide salt precipitation behaviour. These candidates exhibited reasonable iodide uptake in most experimental conditions (average of & mg·g −1 hydrated mass), comparing favourably with literature values for metallated adsorbents. Ag-loaded Purolite S914 (thiourea functionality) was the overall best-performing material, although some salt precipitation was observed in basic conditions. Matrix effects not withstanding it is recommended that metalated thiourea, bispicolylamine, and aminomethylphosphonic acid functionalized silicas warrant further exploration.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 2021
DOI: 10.1016/J.CELREP.2020.108641
Abstract: Central nervous system myelination increases action potential conduction velocity. However, it is unclear how myelination is coordinated to ensure the temporally precise arrival of action potentials and facilitate information processing within cortical and associative circuits. Here, we show that myelin sheaths, supported by mature oligodendrocytes, remain plastic in the adult mouse brain and undergo subtle structural modifications to influence action potential conduction velocity. Repetitive transcranial magnetic stimulation and spatial learning, two stimuli that modify neuronal activity, alter the length of the nodes of Ranvier and the size of the periaxonal space within active brain regions. This change in the axon-glial configuration is independent of oligodendrogenesis and robustly alters action potential conduction velocity. Because aptitude in the spatial learning task was found to correlate with action potential conduction velocity in the fimbria-fornix pathway, modifying the axon-glial configuration may be a mechanism that facilitates learning in the adult mouse brain.
Publisher: Elsevier BV
Date: 06-2022
Publisher: IOP Publishing
Date: 03-2010
Publisher: Wiley
Date: 16-10-2018
DOI: 10.1002/APP.45814
Publisher: Elsevier BV
Date: 02-2020
Publisher: Frontiers Media SA
Date: 13-11-2020
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 07-2019
Publisher: Informa UK Limited
Date: 20-12-2018
Publisher: American Chemical Society (ACS)
Date: 29-05-2019
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JHAZMAT.2018.07.036
Abstract: Spent potlining (SPL) hazardous waste is a potentially valuable source of fluoride, which may be recovered through chemical leaching and adsorption with a selective sorbent. For this purpose, the commercially available chelating resin Purolite
Publisher: Springer Science and Business Media LLC
Date: 13-10-2021
DOI: 10.1007/S42452-021-04818-8
Abstract: Iodine-129 poses a significant challenge in the drive towards lowering radionuclide emissions from used nuclear fuel recycling operations. Various techniques are employed for capture of gaseous iodine species, but it is also present, mainly as iodide anions, in problematic residual aqueous wastestreams, which have stimulated research interest in technologies for adsorption and retention of the radioiodine. This removal effort requires specialised adsorbents, which use soft metals to create selectivity in the challenging chemical conditions. A review of the literature, at laboratory scale, reveals a number of organic, inorganic and hybrid adsorbent matrices have been investigated for this purpose. They are functionalised principally by Ag metal, but also Bi, Cu and Pb, using numerous synthetic strategies. The iodide capacity of the adsorbents varies from 13 to 430 mg g −1 , with ion-exchange resins and titanates displaying the highest maximum uptakes. Kinetics of adsorption are often slow, requiring several days to reach equilibrium, although some ligated metal ion and metal nanoparticle systems can equilibrate in 1 h. Ag-loaded materials generally exhibit superior selectivity for iodide verses other common anions, but more consideration is required of how these materials would function successfully in industrial operation specifically their performance in dynamic column experiments and stability of the bound radioiodine in the conversion to final wasteform and subsequent geological storage. Metallated adsorbents for the capture and retention of radioiodine in the nuclear industry are assessed. The strengths and weaknesses of organic, inorganic and hybrid support matrices and loading mechanisms are discussed. Pathways for progression of this technology are proposed.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.WATRES.2019.04.042
Abstract: A shortage of phosphate rock resources has led to a focus on the use of sewage sludge as a fertiliser. One factor preventing the unlimited application of sewage sludge in agriculture is the heavy metal content. This work looks at a process where weak acid leaching of sewage sludge would be coupled to ion exchange (IX) for heavy metal ion removal. IX offers an effective method for the recovery of these metals from a leachate. This study presents the pH performance of six selected IX resins in extracting Cu
Publisher: Elsevier BV
Date: 10-2019
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: Australia
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2016
End Date: 2021
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2016
End Date: 2019
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2015
End Date: 2018
Funder: Engineering and Physical Sciences Research Council
View Funded Activity