Through-and Out-Diffusion of Se(IV) and Re(VII) in Compacted Bentonite

Abstract

Through-diffusion and out-diffusion are good way to understand anion diffusion behavior in compacted bentonite. In the present work we investigated Re (VII) and Se (IV) diffusion behavior in 2000 kg/m3 compacted GMZ bentonite. The De values of Re (VII) and Se (IV) are 0.29 ± 0.02 and 0.77 ± 0.05× 10-11 m2/s. The result obtained from out-diffusion method was not agreed with predicted data due to the heterogeneous porosity distribution in clay boundaries and species changed when the diffusion occurred in GMZ bentonite. Comparing the Da values of Se, Tc and I in GMZ and Kunigel-F bentonites, it showed that Kunigel-F bentonite hindered the mobilities of anion more efficiently than GMZ bentonite because of the higher content of montmorillonite.