Theoretical investigation of uranyl ion adsorption on hydroxylated γ-Al2O3 surfaces

Abstract

We herein report density functional investigations of uranyl adsorption on γ-Al₂O₃ surfaces. By applying periodic slab models, we report the possible configurations of uranyl adsorbed on the (100) and (110) surfaces of γ-Al₂O₃ by calculations using density functional theory. The above mentioned two surfaces are expected to be highly reactive and adsorb metal ions preferentially. We explored bidentate inner-sphere adsorption complexes of uranyl at short-bridge sites, AlOO, and long-bridge sites, AlOAlO(H). The results indicate several favorable adsorption configurations which fit the available TRLFS and EXAFS data well. Comparison of key calculated structure parameters with available experimental data suggests an extension of the prevailing interpretation and implies that a set of uranyl complexes may coexist on the edge surfaces of γ-Al₂O₃.