CTR diffraction and grazing-incidence EXAFS study of U(VI) adsorption onto α-Al2O3 and α-Fe2O3 (11̄02) surfaces

A comparative study of the effect of desferrioxamine B, oxalic acid, and Na-alginate on the desorption of U(VI) from goethite at pH 6 and 25°C

“…However, the uranyl-carbonato ternary surface complex was not confined to the alkaline pH range but predominant even down to pH 4.5. Crystal truncation rod diffraction, grazing incidence EXAFS, and bond-valance calculations have also identified the presence of a binuclear, bidentate uranyl-carbonate ternary complex on hematite (Catalano et al, 2005). In contrast, in situ attenuated total reflection-infrared spectroscopy detected a binary, inner-sphere, multidentate surface complex of uranyl on hematite (Lefèvre et al, 2006).…”

A surface structural model for ferrihydrite II: Adsorption of uranyl and carbonate

“…In the case of ternary surface complex formation between uranyl and carbonate, the number of CO 3 2À ions present in the UO 2 2+ coordination sphere varies considerably between structural models. For hematite, surface complexes with one (Bargar et al, 1999) and two CO 3 2À ions (Bargar et al, 2000;Catalano et al, 2005) have been suggested. For goethite, the formation of a surface complex with only one CO 3 2À ion in the uranyl coordination sphere has been proposed (Sherman et al, 2008) and this has also been suggested for natural samples (Bostick et al, 2002).…”

Uranyl adsorption and surface speciation at the imogolite–water interface: Self-consistent spectroscopic and surface complexation models

“…More importantly, U(VI) in air-equilibrated hematite systems is known to form U(VI)-carbonate ternary complexes (Bargar et al, 1999(Bargar et al, , 2000. Recent grazing-incidence X-ray absorption spectroscopic studies indicated the formation of innersphere bidentate and outer-sphere complexes on rutile (TiO 2 ) (1 1 0) and (0 0 1) planes, and inner-sphere surface species on a-A 2 O 3 (1 1 0 2) and (1 1 0) surfaces and aFe 2 O 3 (1 1 0 2) surfaces (Den Auwer et al, 2003;Denecke et al, 2003;Catalano et al, 2005).…”