Uranium(VI) and Europium(III) Speciation at the Phosphate Compounds−Solution Interface

• Published in: Langmuir Vol. 15; no. 14; pp. 4820 - 4827
• Main Authors: Drot, Romuald, Simoni, Eric
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 06.07.1999
• Subjects: Chemical Physics; Chemistry; Exact sciences and technology; General and physical chemistry; Physics; Solid-liquid interface; Surface physical chemistry; Sorption; Liquid solid interface; Atom migration; Thorium Phosphates; Europium ion; Uranium ion; Radioisotope; Zirconium Phosphates; network economy; schorlarly publishing; strategic analysis
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la981596v

Prediction of radionuclides migration through a geosphere is of fundamental interest in order to evaluate the safety of an underground radwastes repository. We have studied uranyl and europium(III) ion sorption mechanisms onto three phosphate compounds:  ZrP2O7, Zr2O(PO4)2, and Th4(PO4)4P2O7. A spectroscopic investigation which has been previously reported has allowed one to determine all species involved in the sorption processes under study. This paper presents the modeling of experimental retention data using FITEQLv3.2 code (constant capacitance model). All sorption isotherms were successfully simulated with respect to the structural constraints. We have shown that uranyl sorption onto the solids under study is less influenced by electrostatic interactions between aqueous species and charges on the surface than is that for europium(III) ion. Because many experimental constraints, obtained from independent spectroscopic techniques, have been taken into account for the fitting procedure, the sorption constant values can be determined accurately.