Simulating uranium sorption onto inorganic particles : The effect of redox potential

Degueldre, C. and McGowan, S. (2020) Simulating uranium sorption onto inorganic particles : The effect of redox potential. Journal of Environmental Radioactivity, 225: 106408. ISSN 0265-931X

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An analytical expression is proposed to simulate the effects of pH and redox potential (E) on the sorption of uranium onto model inorganic particles in aquatic environments instead of following an experimental approach providing a list of empirical sorption data. The expression provides a distribution coefficient (Kd) as function of pH, E and ligand concentration (complex formation) applying a surface complexation model on one type of surface sites (>SuOH). The formulation makes use of the complexation and hydrolysis constants for all species in solution and those sorbed at the surface, using correlations between hydrolysis constants and surface complexation constants, for the specific sorption sites. The model was applied for the sorption of uranium onto aluminol, iron hydroxide and silanol sites, mimicking respectively ‘clean’ clay or ‘dirty’ clay and ‘clean’ sand or ‘dirty’ sand (‘dirty’ referring to iron hydroxide contaminated), in absence or presence of carbonates in solution. The calculated distribution coefficients are very sensitive with the presence or absence of carbonates. The Kd values obtained by applying the model are compared with values reported in the literature for the sorption of uranium onto specific adsorbents. It is known that in surface water, U(VI) and its hydroxides are the primary stable species usually observed. However, reduction to U(IV) is possible and may be simulated during sorption or when the redox potential (E) decreases. Similar simulations are also applicable to study the sorption of other redox sensitive elements.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Environmental Radioactivity
Additional Information:
This is the author’s version of a work that was accepted for publication in Journal of Environmental Radioactivity . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Environmental Radioactivity, 225, 2020 DOI: 10.1016/j.jenvrad.2020.106408
Uncontrolled Keywords:
?? distribution coefficientredox potentialsurface complexationuranium sorptionbiogeochemistrycarbonateshydrolysisredox reactionssorptionsurface watersanalytical expressionsaquatic environmentsexperimental approacheshydrolysis constantligand concentrationsurf ??
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Deposited On:
25 Nov 2020 13:25
Last Modified:
15 Jul 2024 21:06