Current understanding and challenges of photocatalytic reduction of U(VI) using polymeric photocatalysts

Uranium, vital for nuclear fuel production, holds immense potential in both the nuclear and environmental sectors. Rising demand for uranium is accompanied by dwindling ore reserves, thus impeding the advancement of sustainable nuclear energy development. Therefore, it is imperative to extract uranium from seawater and radioactive wastewater to ensure the effective utilization of uranium resources and the conservation of the natural environment. Non-homogeneous photocatalysis is recognized for its safe operation, eco-friendly characteristics, and energy-saving functions, which have received considerable attention recently. Given their molecularly adjustable structure, polymer semiconductors, given their molecularly adjustable structure, have demonstrated superior catalytic performance. A marked improvement in photochemical conversion efficiency has been observed with the introduction of advanced synthesis methods. This review aims to elucidate the principle of photocatalytic uranium remediation, critically examining the structural design and uranium removal efficacy of diverse polymer semiconductors, with emphasis on factors such as light absorption, charge separation, and stability. We then delve into the mechanisms of uranium removal by these materials under different environmental conditions, emphasizing their impact on carrier separation and transport, and the reduction of uranium products. Finally, the challenges and prospects of polymer semiconductor photocatalysis in the removal of U(VI) are discussed.