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U redox state and speciation of U in contact with magnetite nanoparticles : High resolution XANES, EXAFS, XPS and TEM study

Pidchenko, I.; Schild, D.; Yokosawa, T.; Kvashnina, K.; Bohnert, E.; Heberling, F.; Finck, N.; Schäfer, T.; Rothe, J.; Geckeis, H.; Vitova, T.

Abstract:
In this work, redox states and speciation of U in U coprecipitated with and sorbed on magnetite nanoparticles are investigated by U M₄ HR-XANES, L₃ EXAFS, XPS and TEM techniques. Coexistence of U(V), U(IV) and U(VI) in varying ratios is clearly detect by the U M₄ HR-XANES technique. Mainly U(V) stable for more than 240 days of contact time is found In a coprecipitated sample with lowest U loading (1000 ppm U). Coprecipitated sample with highest U loading (10000 ppm) undergoes reduction to U(IV) within less than 7 days. Reduction kinetics of U and long term stability of U(V) is discussed for both batch sorption and coprecipitation systems.

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Volltext §
DOI: 10.5445/IR/230102172
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Vortrag
Publikationsjahr 2015
Sprache Englisch
Identifikator urn:nbn:de:swb:90-AAA2301021721
KITopen-ID: 230102172
HGF-Programm 32.27.01 (POF III, LK 01)
Grundlegende Untersuchungen
Veranstaltung 16th International Conference on X-Ray Absorption Fine Structure (XAFS16), Karlsruhe, Germany, 23rd - 28th August 2015
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