MOF modified C3N4 for efficient photo-induced removal of uranium under air without sacrificial agents

Photocatalytic reduction of uranium from U(VI) to U(IV) is an effective method to remove uranium from wastewater, while it often requires anaerobic conditions and/or the addition of sacrificial agents, which hindered its further application. Herein, MOF modified C3N4 composite material was prepared for uranium removal under air atmosphere without the addition of sacrifices, achieving a notably uranium removal capacity of 1355 mg/g. The introduction of MOF enhanced the band structure and the photoelectric properties of C3N4, making it able to generate and separate electrons and holes efficiently. The electrons were applied to reduce O2 to form H2O2 and the holes could oxidize H2O to O2. The generated H2O2 could react with UO22+ to form (UO2)O2.2H2O to realize the solidification of uranium under both air and N2 atmosphere. This work may give new direction of the design of photocatalysts for highly efficient uranium removal under air atmosphere without sacrificial agent.