Adsorption/desorption of uranium on iron-bearing soil mineral surface

In this study, we evaluated the adsorption/desorption of uranium (U) in pure soil environment using continuous column reactor. We additionally investigated the adsorption/desorption mechanism of U on vivianite surface in molecular scale using quantum calculation. We observed that below 0.1μM of U was detected after 20 d from U injection ( 1μM ) in adsorption test. However, all of absorbed U was detached from vivianite surface in 24 h by injection of CARB solution ( 1.44×10⁻²M\;NaHCO₃ and 2.8×10⁻³M\;Na₂CO₃ ). Based on exchange energy calculation, we found that UO₂(CO₃)₂²⁻ and UO₂(CO₃)₃⁴⁻ species have higher repulsive energy than UO₂(OH)₂ species. The results obtained from this study could be applied to predict the behavior of uranium in contaminated and remediation sites.