XAS signatures of Am(III) adsorbed onto magnetite and maghemite

16th International Conference on X-ray Absorption Fine Structure

Finck, N.^1 ; Radulescu, L.^1 ; Schild, D.^1 ; Rothmeier, M.^1 ; Huber, F.^1 ; Lützenkirchen, J.^1 ; Rabung, T.^1 ; Heberling, F.^1 ; Schlegel, M.L.^2 ; Dideriksen, K.^3 ; Nedel, S.^3 ; Geckeis, H.^1

Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), P O Box 3640, Karlsruhe

D-76021, Germany^1

CEA, DEN, DPC/SEARS/LISL, Bât. 391, Gif-sur-Yvette

F-91191, France^2

Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen

DK-2100, Denmark^3

关键词: Chemical conditions;    Coordination number;    Fe atoms;    Fe oxide;    Local environments;    Maghemites;    Surface complex;    XPS data;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012085/pdf
DOI  :  10.1088/1742-6596/712/1/012085

来源: IOP

【 摘 要 】

Trivalent americium was adsorbed on magnetite and maghemite under similar chemical conditions and the local environment probed by EXAFS spectroscopy. In both samples, partially hydrated Am(III) binds the surface but slightly different surface complexes were identified. On Fe3O4, Am(III) forms monomeric tridentate surface complexes similar to that reported for Pu(III) at the (111) surface. In contrast, the lower number of detected Fe atoms may suggest that Am(III) forms monomeric bidentate surface complexes on γ-Fe2O3. Alternatively, the lower Fe coordination number can also be due to the presence of vacancies in maghemite. XPS data imply very similar binding environments for Am at both Fe oxide surfaces.