Electrochemical upcycling of uranyl from radioactive organic wastewater with a self-standing covalent-organic framework electrode

Abstract

Efficient upcycling of uranyl from uranyl–containing radioactive organic wastewater is of utmost importance for the sustainable development of nuclear energy. In this work, an indirect electrochemical method to upcycle uranyl from radioactive organic wastewater is proposed. A cost-efficient self-standing polyarylether-based covalent organic framework electrode (PAE-COF-AO@CC) not only acts as an oxygen reduction reaction (ORR) catalyst for hydrogen peroxide (H₂O₂) production, but also provides chelating sites for uranyl ions and nucleation center for the following growth of studtite originating from the reaction between H₂O₂ and chelated uranyl. It’s clarified that the up-take studtite on PAE-COF-AO@CC electrode could transform to high-pure U₃O₈ after calcinating the permanently used PAE-COF-AO@CC electrode. The ultra-long lifespan of longer than 450 h and the excellent uranyl capacity of 9238.9 mg/g from the continuous accumulation of studtite make the self-standing PAE-COF-AO@CC electrode as promising materials for the uranyl resource upcycling from the complicated organic waste water matrix.