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Naji, M. |
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Motta, Antonella |
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Aletan, Dirar |
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Mohamed, Tarek |
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Ertürk, Emre |
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Taccardi, Nicola |
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Kononenko, Denys |
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Petrov, R. H. | Madrid |
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Alshaaer, Mazen | Brussels |
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Bih, L. |
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Casati, R. |
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Muller, Hermance |
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Kočí, Jan | Prague |
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Šuljagić, Marija |
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Kalteremidou, Kalliopi-Artemi | Brussels |
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Azam, Siraj |
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Ospanova, Alyiya |
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Blanpain, Bart |
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Ali, M. A. |
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Popa, V. |
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Rančić, M. |
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Ollier, Nadège |
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Azevedo, Nuno Monteiro |
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Landes, Michael |
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Rignanese, Gian-Marco |
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Shaw, Samuel
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Topics
Publications (9/9 displayed)
- 2022Hydrotalcite colloid stability and interactions with uranium(VI) at neutral to alkaline pH.citations
- 2021A spectroscopic study of trivalent cation (Cm3+ and Eu3+) sorption on monoclinic zirconia (ZrO2)citations
- 2019U(VI) sorption during ferrihydrite formation: Underpinning radioactive effluent treatmentcitations
- 2019A spectroscopic study of trivalent cation (Cm3+ and Eu3+) sorption on monoclinic zirconia (ZrO2)citations
- 2018Stability, composition and core-shell particle structure of uranium(IV)-silicate colloidscitations
- 2016Release of Ni from birnessite during transformation of birnessite to todorokite: Implications for Ni cycling in marine sedimentscitations
- 2014Nucleation and growth of todorokite from birnessite: Implications for trace-metal cycling in marine sedimentscitations
- 2013Partitioning of Pb(II) during goethite and hematite crystallization: Implications for Pb transport in natural systemscitations
- 2006The rate of ferrihydrite transformation to goethite via the Fe(II) pathwaycitations
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article
Hydrotalcite colloid stability and interactions with uranium(VI) at neutral to alkaline pH.
Abstract
In the UK, decommissioning of legacy spent fuel storage facilities involves the retrieval of radioactive sludges that have formed as a result of corrosion of Magnox nuclear fuel. Retrieval of sludges may re-suspend a colloidal fraction of the sludge, thereby potentially enhancing the mobility of radionuclides including uranium. The colloidal properties of the layered double hydroxide (LDH) phase hydrotalcite, a key product of Magnox fuel corrosion, and it’s interactions with U(VI) are of interest. This is because colloidal hydrotalcite is a potential transport vector for U(VI) under the neutral-to-alkaline conditions characteristic of the legacy storage facilities and other nuclear decommissioning scenarios. Here, a multi-technique approach was used to investigate the colloidal stability of hydrotalcite and the U(VI) sorption mechanism(s) across pH 7 – 11.5 and with variable U(VI) surface loadings (0.01 – 1 wt%). Overall, hydrotalcite was found to form stable colloidal suspensions between pH 7 and 11.5, with some evidence for Mg2+ leaching from hydrotalcite colloids at pH ≤ 9. For systems with U present, >98% of U(VI) was removed from solution in the presence of hydrotalcite, regardless of pH and U loading, although the sorption mode was affected by both pH and U concentration. Under alkaline conditions, U(VI) surface precipitates formed on the colloidal hydrotalcite nanoparticle surface. Under more circumneutral conditions, Mg2+ leaching from hydrotalcite and more facile exchange of interlayer carbonate with the surrounding solution led to the formation of uranyl carbonate species (e.g. Mg[UO2(CO3)3]2-(aq)). Both X-ray absorption spectroscopy (XAS) and luminescence analysis confirmed these negatively charged species sorbed as both outer- and inner-sphere tertiary complexes on the hydrotalcite surface. These results demonstrate that hydrotalcite can form pseudo-colloids with U(VI) under a wide range of pH conditions and have clear implications for understanding uranium behaviour in environments where hydrotalcite and other LDHs may be present.