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 Zn2SnO4/SnO2 as piezo catalyst. The electrons and holes in Zn2SnO4/SnO2 are separated efficiently under the irradiation of ultrasound. After that, some of the piezo electrons reduce the adsorbed U(VI) to UO2, the others react with soluble oxygen to form H2O2, and oxidize UO2 to generate (UO2)O2∙2H2O, 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.