The diffusion behavior of Re(VII) in bentonite with low porosity

The diffusion behavior of Re(VII) in bentonite with low porosity was investigated by the capillary method at different SO₄²⁻ concentrations, dry densities, pH values and ionic strengths. The batch experiment results revealed that the D_a values decreased with increasing SO₄²⁻ concentration and dry density. This is mainly due to CaSO₄ precipitation blocking pore water channels to form low-porosity bentonite, and the porosity of bentonite with low porosity decreases as the dry density increases. In contrast, the influence of pH on the diffusion behavior of Re(VII) is relatively small. Moreover, the D_a values increase as the ionic strength increases because the free water pore channels widen.