Rights statement: 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
Accepted author manuscript, 661 KB, PDF document
Available under license: CC BY-NC-ND
Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Simulating uranium sorption onto inorganic particles
T2 - The effect of redox potential
AU - Degueldre, C.
AU - McGowan, S.
N1 - 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
PY - 2020/12/1
Y1 - 2020/12/1
N2 - 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.
AB - 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.
KW - Distribution coefficient
KW - Redox potential
KW - Surface complexation
KW - Uranium sorption
KW - Biogeochemistry
KW - Carbonates
KW - Hydrolysis
KW - Redox reactions
KW - Sorption
KW - Surface waters
KW - Analytical expressions
KW - Aquatic environments
KW - Experimental approaches
KW - Hydrolysis constant
KW - Ligand concentration
KW - Surface complexation modeling
KW - Iron compounds
U2 - 10.1016/j.jenvrad.2020.106408
DO - 10.1016/j.jenvrad.2020.106408
M3 - Journal article
VL - 225
JO - Journal of Environmental Radioactivity
JF - Journal of Environmental Radioactivity
SN - 0265-931X
M1 - 106408
ER -