U(VI) Sorption and Reduction by Fe(II) Sorbed on Montmorillonite
- Chakraborty, Sudipta
- Favre, Fabienne
- Banerjee, Dipanjan
- Scheinost, Andreas C.
- Mullet, Martine
- Ehrhardt, Jean-Jacques
- Brendle, Jocelyne
- Vidal, Loic
- Charlet, Laurent
DOIAbstract
International audienceThe influence of surface-bound Fe(II) on uranium oxidation state and speciation was studied as a function of time (6 min−72 h) and pH (6.1−8.5) in a U(VI)−Fe(II)-montmorillonite (Ca-montmorillonite, MONT) system under CO2-free, anoxic (O2 <1 ppmv) conditions. The results show a rapid removal of U(VI) from the aqueous solution within 1 h under all pH conditions. U LIII-edge X-ray absorption near-edge structure spectroscopy shows that 96% of the total sorbed U(VI) is reduced at pH 8.5. However, the extent of reduction significantly decreases at lower pH values as specifically sorbed Fe(II) concentration decreases. The reduction kinetics followed by X-ray photoelectron spectroscopy during 24 h at pH 7.5 demonstrates the p...
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