Highly efficient uranium extraction by a piezo catalytic reduction-oxidation process

In this work, a highly efficient uranium extraction method from water by the piezo catalytic reduction-oxidation process is reported by utilizing a hollow cubic shaped Zn 2 SnO 4 /SnO 2 as piezo catalyst. The electrons and holes in Zn 2 SnO 4 /SnO 2 are separated efficiently under the irradiation of ultrasound. After that, some of the piezo electrons reduce the adsorbed U(VI) to UO 2 , the others react with soluble oxygen to form H 2 O 2 , and oxidize UO 2 to generate (UO 2 )O 2 ∙2H 2 O, which could be efficiently separated from the solution. U(VI) piezo catalytic extraction rate could reach ~ 90% under the irradiation of ultrasonic waves (40 kHz, 120 W) within 5 h and only decreased by ~ 3% after four cycles. The present work advances piezo catalysis as a new route for uranium extraction from water, which may be applied in the extraction or removal of U(VI) in the U-containing wastewaters, providing new opportunities for resource-saving and environmental enhancement.