Sorption of Se(-II): Batch Sorption Experiments on Limestone and Multi-Site Sorption Modelling on Illite and Montmorillonite

Abstract

Selenium is an important radionuclide in used nuclear fuel. Sorption behavior of Se(-II) under reducing conditions has been further understood by a combination of experimental measurements and surface complexation sorption modelling. Sorption experimental measurements were conducted for limestone in highly saline Na-Ca-Cl solutions with ionic strengths ranging from 0.1 to 6.0 mol/kgw(m). These sorption experiments were also conducted over a pH range from 4-9. Se(-II) sorption on limestone required14 daysto achieve sorption equilibrium. Sorption modelling of Se(-II) on illite and montmorillonite has been conducted over a wide pH range of 3-10. There is a general decrease in the sorption of Se(-II) on illite, bentonite, and limestone with increasing pH.