Quantum chemical modeling of uranyl adsorption on mineral surfaces

Abstract

We overview quantum mechanical simulations that model the adsorption of actinide ions at solvated mineral surfaces. Pertinent examples illustrate the status of this emerging field of computational chemistry. In particular, we describe our own studies on uranyl adsorption on kaolinite. Already the few available results, from applications of density functional methods to cluster models or periodic slab models, show that such calculations are a useful complement to experimental investigations. Detailed information at the atomic level from accurate electronic structure calculations on well defined model systems helps to refine current interpretations of the chemical nature of uranyl adsorption species and to discover new features of these interface systems. Results from quantum mechanical simulations also provide a valuable reference for future experimental investigations.

A combined DFT and molecular dynamics study of U(VI)/calcite interaction in aqueous solution

“…The probable ion exchange reactions with the first-layer surface Ca atoms have also been studied for the first time. The surface solvation energy of minerals was either neglected [13,15] or assumed to be unchanged [20,21] in previous DFT investigations. This approximation simplified the difficulty in modeling periodic boundary systems, but left an open question: to what degree does uranyl adsorption influence the surface solvation energy of minerals.…”

“…For example, Kremleva et al. [20,21] introduced silanol groups to neutralize the supercell when modeling uranyl adsorption on the (0 0 1) surface of kaolinite. In their work, the solvation energy of the kaolinite surface was assumed to be unchanged after uranyl adsorption.…”

Application of Density Functional Theory in Soil Science

“…) form [14,15] and DFT calculations have been conducted to understand the adsorption of UO 2 2+ onto mineral surfaces [16][17][18][19][20][21][22][23][24][25]. ) interacts more strongly with anionic ligands…”

“…Kaolinite is the major constituent of sedimentary clay rocks, and adsorption of uranyl species onto its (001) surface [20,21] and (010) edge surface [22,23] have been theoretically studied. The adsorption of uranyl species on tetrahedral SiO 4 surfaces is thermodynamically unfavorable, with the adsorption energies of inner-and outer-sphere complexes being, respectively, 239 and 206 kJ/mol [20]; in contrast, the adsorption at octahedral AlO 6 surfaces is preferred due to the presence of upright (perpendicular to the surface) and lying (parallel to the surface) OH groups.…”

Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

“…Molecular simulation techniques have been used to study uranyl sorption at mineral surfaces (Kremleva et al 2010;Geckeis et al 2013). Mineral surfaces have included silica (Greathouse et al 2002;Patsahan and Holovko 2007;Boily and Rosso 2011), alumina (Moskaleva et al 2004;Glezakou and deJong 2011;Tan et al 2013), iron and titanium oxides (Steele et al 2002;Perron et al 2006aPerron et al ,b, 2008Drot et al 2007;Sherman et al 2008;Roques et al 2009;Skomurski et al 2011;Pan et al 2012;Sebbari et al 2012) , phyllosilicates (Zaidan et al 2003;Cygan 2005, 2006;Kremleva et al 2008Kremleva et al , 2011Kremleva et al , 2012Veilly et al 2008;Hattori et al 2009;Martorell et al 2010;Lectez et al 2012;Liu et al 2013b;Yang and Zaoui 2013a,b;Teich-McGoldrick et al 2014); feldspars Liu 2012, 2014), and carbonates (Doudou et al 2012).…”