Glauconite as model material for examining deactivation of uranium-containing soils

Abstract

Sorption of U(VI) on a clay illite mineral glauconite from Osykovo deposit was examined in relation to the sorption time, pH, and presence of EDTA. The equilibrium in the radionuclide-glauconite system is established within 24 h. The pH dependence of the degree of sorption has a distinct maximum at pH 4–6, characteristic for U sorption on aluminosilicates. The sorption data were interpreted in terms of the constantcapacity surface complexation model. It was shown that uranium is sorbed predominantly as (≡SO)2UO2 and ≡SO(UO2)3(OH)5 complexes. The EDTA occurring in solution substantially decreases the degree of sorption. An isotherm of U(VI) sorption on glauconite was obtained, which is adequately described by the empirical Langmuir equation. Desorption of U with various reagents under dynamic conditions was carried out. It was shown that EDTA is suitable as desorbing reagent for treatment of uranium-containing soils.