Adsorption of Y(III) on the Interface of Kaolinite-H2O: A DFT Study

Abstract

Ion-adsorbed rare earth minerals have rare earth ions adsorbed on the surfaces of clay minerals such as kaolinite and have high contents of medium and heavy rare earth elements. They are important resources supporting the development of high-tech industries. In this study, the CASTEP module in Materials Studio was used to study the adsorption of the rare earth ion Y(III) on the interface of (Al-OH)-H2O and (Si-O)-H2O with density functional theory. The monitoring and calculation of the chemical bond of the adsorption structure showed that Y(III) on the (Al-OH)-H2O interface has a bond with O32, O34, and water molecules in the interface. In the (Si-O)-H2O interface, Y(III) interacts with O3, O4, and O10 to form new chemical bonds. The Mulliken population and density of states analysis showed that Y(III) bonds with surface oxygen atoms and water molecules in the kaolinite-H2O interface, and finally adsorbs on the surface of kaolinite in the form of metal ion hydrate.