Rapid removal of uranium from wastewater via Cu-based single-atom catalyst/carbon nitride composite electrode under photoelectric cooperative catalysis

The removal and recovery of uranium from radioactive wastewater are crucial for environmental protection. A photoelectric cooperative catalysis method using Cu-SA/g-C 3 N 4 electrodes has been proposed for the efficient removal and recovery of uranium. The uranium removal efficiency achieves 98.8 % within just 5 min for a 10 mg/L uranium solution at pH 6. The removal rate under photoelectric cooperative catalysis is 22 times higher than that under photocatalytic alone and 12 times higher than that under electrocatalysis alone. Compared to the Cu-based single-atom catalyst electrode, the electrocatalytic uranium removal process achieves a significant reduction in time, decreasing from 180 min to 5 min, which is considerably higher than that reported in the prior literature. The results of PXRD and Raman analysis indicate that the adsorbed uranyl species are initially reduced to unstable U(V) intermediates, which are subsequently oxidized to form Na 2 O(UO 3 ·H 2 O) x deposits. The synergistic advantages of photocatalysis and metal single-atom catalysts are fully utilized to achieve rapid uranium deposition and removal without occupying the electrode's adsorption sites. The cyclic experiment demonstrates an exceptionally high uranium adsorption capacity of 8954 mg/g, with no signs of saturation. The uranium removal rate by the Cu-SA/g-C 3 N 4 electrode from real wastewater is 100 % within 30 min. In summary, the photoelectric cooperative catalytic system enables highly efficient uranium removal, thereby establishing a robust foundation for the removal and recovery of uranium from wastewater.