Adsorption of the uranyl ion on the hydroxylated α-quartz (101) surface

Abstract

Uranyl ion adsorption on the hydroxylated α- quartz (101) surface was investigated by firstprinciples density functional theory calculations. We explicitly considered the first hydration shell of the uranyl ion for short-range solvent effects and used the conductor-like screening model (COSMO) for longrange solvent effects. Both the adsorption energies and electronic structures of the adsorption system indicated that the bidentate hydrated uranyl species were more stable than bidentate hydroxylated species, and bidentate adsorption of the uranyl ion on the bridge site of dia-Os1Os2 was the most stable adsorption model in the aqueous state. The large differences in the electronic structures of the two forms were mainly because of the different degree of bonding between uranium and the surface after adsorption, which makes the 5f orbital narrow and causes a red shift. Use of halogen ions in the uranyl coordination environment can adjust the band gap of the uranyl adsorption system.