Photocatalytic reduction of uranium(VI) by g-C3N4/P25-TiO2 composite under full spectrum

Photocatalytic reduction of soluble uranium(VI) to insoluble uranium(IV) is a promising approach for removing uranium(VI) from aqueous solutions. In this work, a g-C 3 N 4 /P25-TiO 2 type-II heterojunction composite was fabricated by ultrasonic dispersion method for photocatalytic uranium(VI) reduction under full spectrum. Characterization confirmed the successful formation of g-C 3 N 4 /P25-TiO 2 composites. The optimized g-C 3 N 4 /P25-TiO 2 composite showed markedly enhanced charge separation and light absorption, and its reaction rate for uranium(VI) removal was 3.9 times that of P25. Photocatalytic performance depended on solution pH, uranium(VI) concentration, light source, hole scavenger and coexisting metal ions. In the presence of hole scavenger, the catalyst achieved a maximum uranium(VI) removal efficiency of 99.8% and retained high activity after five cycles. The energy levels of g-C 3 N 4 and TiO 2 are well matched, forming a type-II heterojunction that promotes charge-carrier separation. The prepared g-C 3 N 4 /P25-TiO 2 composite offers a simple and low-cost strategy for treating uranium-containing wastewater.