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Lu(III) coprecipitation with hectorite: a P-EXAFS approach

Finck, N.; Schlegel, M.L.; Bosbach, D.

Abstract:
Various secondary phases may form upon alteration of the High Level nuclear Waste (HLW) glass over geological time scales, including hectorite [1] (a magnesian smectite). Such secondary phases represent a significant retention potential for radionuclides (RNs), including actinides. In addition to (surface) adsorption reactions, effective RN incorporation into the bulk structure may occur by coprecipitation. Recently, hectorite was coprecipitated in the presence of the trivalent lanthanide Eu(III) [2], as non-radioactive chemical homologue for trivalent actinides. Time-resolved laser fluorescence spectroscopy data suggested that Eu(III) substitutes for cations at octahedral position.
Polarized EXAFS (P-EXAFS) experiments [3] were performed on Lu(III)-containing samples associated with the hectorite multi-step synthesis protocol [4]. P-EXAFS spectra were collected for the (Mg/Lu) hydroxide precursor and the Lu(III)-coprecipitated hectorite at different angles a between the electric field vector of the X-ray beam and the mineral layer plane. The modeling results for the oxygen shell (d(Lu-O) = 2.27 Å) strongly suggest that Lu(III) is ... mehr


Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Zeitschriftenaufsatz
Jahr 2009
Sprache Englisch
Identifikator ISSN: 0016-7037, 1872-9533
KITopen ID: 120076664
HGF-Programm 32.27.01; LK 01
Erschienen in Geochimica et cosmochimica acta
Band 73
Heft 13
Seiten A376
Erscheinungsvermerk 19th Annual V.M. Goldschmidt Conf., Davos, CH, June 21-26, 2009, Suppl.1, (Abstract)
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