Decontamination studies of the uranium sludge waste consisting of hundreds ppm of uraniumand tens thousands ppm of salts such as NH4NO3, NaNO3, Ca(NO3)2 have been carried out by electrosorption ona carbon electrode composed of activated carbon fibers(ACFs) in a continuous flow-through cell by varying pHand potential. Effective uranium (Ⅵ) removal was accomplished when a negative potential in the range of -0.3 to-0.9V (vs. Ag/AgCl) was applied to the carbon electrode. For a feed concentration of 100-350mg/l, theconcentration of U(Ⅵ) in the cell effluent was reduced to less than 1mg/l which was low enough toenvironmental release. And the electrosorption capacity over 600 mg uranium/g ACF was reached. It was foundthat the principle mechanism of the uranium removal was by reductive precipitation on the ACF surface inducedby lowering the electropotential.
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