Simultaneous diffusion of Re(VII) and Se(IV) in compacted Tamusu clay by capillary method

This paper presents the first laboratory-based, simultaneous diffusion experiments of Re(VII) and Se(IV) in Tamusu (TMS) clay, using the capillary method. We determined diffusion coefficients (Da) and adsorption values (Kd) for these nuclides under varying clay compaction densities, solution pH values, ionic strengths, and in the presence of humic acid (HA). The results indicated rapid acquisition of diffusion data, the Da values predominantly ranging from 10−9 m2/s to 10−10 m2/s, and weak adsorption for both Re(VII) and Se(IV). While the presence of HA augmented the Da and Kd values for Re(VII) and Se(IV) diffusion in clay, these values did not exhibit significant alterations in response to increasing HA concentrations.