Molecular dynamics modeling of uranyl ion adsorption onto the basal surfaces of kaolinite

Abstract

We performed a molecular dynamics simulation to investigate the adsorption of uranyl ions onto the basal surfaces of kaolinite using a simulation cell containing 0.01 mol·L-1 uranyl carbonate and 9× 9×3 kaolinite unit cells. The adsorption sites of the uranyl ions on kaolinite were clearly shown by serial snapshots and the coordination of uranyl ions to oxygen were determined using a radial distribution function. The adsorption trends of uranyl ions on two distinct basal surfaces were discussed using an atomic density profile. Outer-sphere complexation of uranyl on kaolinite was confirmed using the atomic density profile and the mean squared displacement. Confirmation of the outer-sphere complexation supports the theoretical simplification of the adsoption sites in the surface complexation model. © Editorial office of Acta Physico-Chimica Sinica.