Cluster-Models for Uranyl(VI) Adsorption on α-Alumina

Abstract

Aqueous complexation, adsorption, and redox chemistry of actinide species at mineral surfaces have a significant impact on their transport and reactive behavior in chemically and physically heterogeneous environments. The adsorption configurations and energies of microsolvated uranyl dication species, UO(2)(H(2)O)(n)(2+), were determined on fully hydroxylated and proton-deficient α-alumina(0001)-like finite cluster models. The significant size of the models provides faithful representations of features that have emerged from periodic calculations, but most importantly, they afford us a systematic study of the adsorption mechanism, the effect of secondary solvation shells and an explicit treatment of the total charge. Based on this cluster representation, the energetics computed from the difference between the optimized structures and the appropriate reference states point to a preference for an inner-sphere type complex.

Uranyl adsorption on solvated edge surfaces of pyrophyllite: a DFT model study

“…[11][12][13][14][15][16] In addition, computational methods are becoming popular in this field. 17 Density functional calculations have been carried out to study uranyl adsorption on the surfaces of a-alumina, 18,19 kaolinite, 20,21 and gibbsite. 22 Thus far, only force-field based molecular dynamics simulations were used to explore uranyl adsorption on basal surfaces of 2 : 1 clays, i.e.…”

Surface Modification of Graphene Oxides by Plasma Techniques and Their Application for Environmental Pollution Cleanup

“…The DFT calculation results showed that the binding energy ( E bd ) of [HOOC‐GOs···UO 2 ] 2+ (12.1 kcal/mol) was greater than that of [GOs‐O···UO 2 ] 2+ (10.2 kcal/mol), suggesting that favored binding with the –COOH group over the –O– group. The low E bd value of [G···UO 2 ] 2+ (8.1 kcal/mol) indicated that the sorption of U(VI) on rGOs was physical adsorption (8 kcal/mol) . The higher E bd values of [GOs···U(OH)O 2 ] 2+ (45.5 kcal/mol) and [GOs‐OH···U(OH)O 2 ] 2+ (42.8 kcal/mol) were attributed to OH abstraction from GOs, resulting in the chemical sorption of U(VI) on GOs and HOOC‐GOs (Figure ).…”

The adsorption of CO2, H2CO3, HCO3− and CO32− on Cu2O (111) surface: First‐principles study

“…To mimic the surface, we employed the embedded cluster method, an accepted and used widely method in metal oxide catalysts surfaces simulating, [44,45] and constructed two embedded cluster models with experimental lattice constant as seen in Figure 2. The embedded cluster models consisted of 18 atomic layers, and every layer was in the symmetry of C 3v (around Zaxis).…”