Sorption of Eu(III) by amorphous titania, anatase and rutile: Denticity difference in surface complexes

Metal Oxide Sorbents for the Separation of Radium and Actinium

“…Second, the mechanism of rare-earth and trivalent actinide adsorption by selected mineral oxide surfaces has been the focus of a large number of studies within the context of radionuclide migration and uptake from repositories. − The lanthanide ions undergo surface complexation with hydroxyl groups in a cation-exchange manner, where ≡ X represents the metallic support Al, Ti, or Zr and M represents the metal ion. The hydration information is supported by time-resolved laser-induced fluorescence of either Eu or Cm . Based on radius to charge ratios, the Ba ion should be retained to a lesser extent compared to a La cation, which is evident in Figures and for alumina and zirconia.…”

Simultaneous removal of Pb2+, Cu2+, Zn2+ and Cd2+ from highly acidic solutions using mechanochemically synthesized montmorillonite–kaolinite/TiO2 composite

“…difference in the dominant crystal orientations of TiO 2 that resulted in the presence of various types of oxygen binding to titanium atoms. Distribution of these sites of different acidities on the dominant planes of the different titania phases may cause the observed difference in pH response (Kasar et al, 2013). Thus, in the case of the mechanochemically synthesized Mt-K/TiO 2 ,a, it can be concluded that the crystalline structure of TiO 2 (present in 20 wt.% of the sample) well dispersed on the clay matrix (80 wt.% of the sample) determined its adsorption behavior.…”

“…It was attributed to the smaller particles, disordered surface structure and high surface area as well as higher adsorption site density (Kanna et al, 2005); Then, Huang et al (2012) investigated the adsorption of Pb 2+ ions on different titanate structure and reported that titanate nanoflowers exhibit better adsorption ability to all selected heavy metal-ions compared to titanate nanowires and nanotubes. It was attributed to its micrometer-size overall structure, composed of many ultra-thin nanosheets that can provide facile mass transportation; Further, Xie and Gao (2009) reported strong dependence of adsorption capacity of TiO 2 from its crystalline structure: higher chemisorption capacity of anatase compared to rutile can be attributed to higher surface energy, rough surface and unsaturated oxygen bond, that provided an easier chemisorption of cations and easy forming of cation-surface oxygen complexes or easy penetration of cation into the structural voids, under the top of the surface mineral layer; also, Kasar et al (2013) investigated the adsorption of Eu 3+ by amorphous titania, anatase and rutile and showed that the difference in acidic/basic pH response of different titania suspensions can be understood by taking into consideration the difference in the structural characteristics of titania phases, i.e. difference in the dominant crystal orientations of TiO 2 that resulted in the presence of various types of oxygen binding to titanium atoms.…”

A Combined Extended X-ray Absorption Fine Structure Spectroscopy and Density Functional Theory Study of Americium vs. Yttrium Adsorption on Corundum (α–Al2O3)

“…Even in the case of simple oxides, such as Al 2 O 3 , Fe 2 O 3 , MnO 2 , or TiO 2 , which do not have an interlayer space for cation attachment or a permanent negative charge allowing for cation exchange reactions, sorption investigations have shown that the presence of different surface planes or different surface sites may influence the speciation of the metal ion at the oxide interface [6,[23][24][25][26][27][28][29][30][31]. As an example, Den Auwer et al (2003) [31] investigated the sorption of uranyl on different surface planes of rutile (TiO 2 ) as well as on polycrystalline powder.…”