Efficient photoreduction strategy for uranium immobilization based on graphite carbon nitride/activated carbon nanocomposites

Uranium removal from aqueous solutions using environmentally friendly photocatalytic technology is a novel approach for resource recovery. Herein, carbon nitride/activated carbon composite materials (CN/AC) were investigated for U(VI) reduction under visible light. An exceptional boost in photocatalytic activity was observed for CN/AC composites (up to 70 times over the conventional bulk g-C3N4). The strong interactive conjugated pi-bond structure between g-C3N4 and AC accelerated the migration of carriers and then prolonged the electron lifetime. CN/AC composites exhibited excellent compatibility with different water substrates and were resilience to a wide range of pH changes and abundant competitive anions/cations. Quenching experiments and electron microscopy characterization indicated that U(VI) was reduced by photogenerated electrons and deposited on the edge of CN/AC composites. The low-cost, high-performance carbon-based composite material proposed in this work is a potential candidate for the efficient treatment of radioactive wastewater. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.