Kinetics of the Laser Induced Photoreduction of U(VI) in Aqueous Suspensions of TiO2 Particles.
The reduction of U(IV) in aqueus suspensions of TiO2 (pH 4.5 to 7) was investigated by Time-Resolved Laser Induced Fluorescence (TRLIF). The laser irradiation was used both to provide the energy necessary for the photogeneration of charge carriers, and to monitor the kinetics of the oxidation state change directly in the measurements cuvette by exciting the U(VI) fluorescence. The U(VI) photoreduction was found to involve only adsorbed Uranium species. The TRLIF measurements of U(VI) fluorescence lifetimes and individual emission fluorescence spectra allowed a selective identification of the various U(VI) hydro-complexes present in the aqueous phase and adsorbed on the mineral surface. a reaction mechanism is proposed based on the kinetics results obtained at pH 7 where adsorption of the hydro-complex (UO2)3(OH)5 on TiO2 is complete.
ELIET Veronique;
BIDOGLIO Giovanni;
1998-09-21
JRC16838
https://publications.jrc.ec.europa.eu/repository/handle/JRC16838,
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