Adsorption and diffusion of selenite on Boda Claystone Formation

This study provides adsorption and diffusion data of selenite on Boda Claystone Formation (BCF) which is a potential host rock deep geological disposal high-level radioactive waste. The experiments were performed two diverse core samples: one albitic claystone sample characteristic for the entire BCF pyrite containing sparsely occurring in BCF. carried out under atmospheric conditions. Batch to kinetics at high initial concentration (1.2 × 10−3 M), isotherms reversibility investigated 10−10–10−3 M range. Adsorption onto petrographic thin sections was done elemental distribution microscale oxidation state selenium. maximum coefficient found as Kd ≈ 200 L/kg decrease experienced around 10−6–10−7 equilibrium concentration, showed similarities other argillaceous rocks. Isotopic exchange revealed adsorption. Diffusion studied with through-diffusion in-diffusion experiments. Using X-ray fluorescence, despite low 2.3 10−5 experiment, meaningful profile selenium could be obtained, from apparent Dappselenite = (1.5–4.3) 10−14 m2/s capacity factor αselenite 1.4–2.2 determined. As species are redox sensitive adsorbed absorption near edge structure spectroscopy SeK edge. Adsorbed remained +IV state, however reduction pyritic sample.