[1D01-04] Sorption/Adsorption

[1D03] Sorption behavior of selenite ions onto calcium silicate hydrate under the water-saturated condition

*Kazuki Maeta¹, Tsugumi Seki¹, Taiji Chida¹, Yuichi Niibori¹ (1. Tohoku Univ.)

Keywords:calcium silicate hydrate, selenite ions

Selenium, an important radionuclide in assessment for geological disposal, may exist as selenite ions in underground environments with high pH. Whereas, C-S-H, which is formed by leached silicate and cement-derived Ca in high pH environments, is expected to have nuclide sorption capacity. In this study, the interaction of C-S-H with selenite ions was investigated when C-S-H was brought into contact with selenite ions without any drying process from its formation. In the experiments, powdered CaO and SiO₂ were mixed with Na₂SeO₃ solution. The results show that more than 80 % of Se was sorbed to the solid phase side in all conditions, suggesting that the sorption is due to precipitation formation of CaSeO₃ and interaction of C-S-H with Ca.