Implanting open active pairs into open flower-structured Cu-S-O nanosheets for electrochemical uranium extraction in radioactive wastewater

Electrochemical uranium extraction in real nuclear wastewater containing ultrahigh concentration of F - is challenging, which requires the development of extraction material with highly exposed active sites for dominant uranyl complex species. Herein, we implant open active pairs of Cu + -SO x on an open flower-structured Cu-S-O nanosheets by pulse electro-oxidation, enabling the efficient electrochemical uranium extraction in real nuclear wastewater with F - . In this case, the open structure ensures the sufficient contact with electrolyte, together with the open active pairs selective binding with the dominant UO 2 F x species. In simulated nuclear wastewater, the open Cu-S-O nanosheets with open active pairs possessed an optimum extraction efficiency of 98.6 % in 300 min, which was 1.2-time larger than that of CuS nanosheets. Moreover, the Cu-S-O nanosheets maintained the remarkable efficiency regardless of the variation of pH, the interfering ions, and the ratio of U/F. The mechanistic study revealed an evolution of UO 2 F x adsorption, uranium reduction, and UO 2.34 crystallization. In real acidic nuclear wastewater from the fabrication of fuel element, the Cu-S-O nanosheets electrochemical extracted 95.6 % of the uranium, with a facile collection of the uranium oxide product.