Efficient and durable uranium extraction from uranium mine tailings seepage water via a photoelectrochemical method

Summary Current photocatalytic uranium (U) extraction methods have intrinsic obstacles, such as the recombination of charge carriers, and the deactivation of catalysts by extracted U. Here we show that, by applying a bias potential on the photocatalyst, the photoelectrochemical (PEC) method can address these limitations. We demonstrate that, owing to efficient spatial charge-carriers separation driven by the applied bias, the PEC method enables efficient and durable U extraction. The effects of multiple operation conditions are investigated. The U extraction proceeds via single-step one-electron reduction, resulting in the formation of pentavalent U, which can facilitate future studies on this often-overlooked U species. In real seepage water the PEC method achieves an extraction capacity of 0.67 gU m−3·h−1 without deactivation for 156 h continuous operation, which is 17 times faster than the photocatalytic method. This work provides an alternative tool for U resource recovery and facilitates future studies on U(V) chemistry.
Graphical abstract
Highlights • Efficient and durable U extraction by a photoelectrochemical method • Spatial separation of charge carriers is achieved by the applied bias potential • Stable pentavalent U is produced under ambient conditions • The proposed photoelectrochemical method is economically feasible
Chemistry; Environmental chemical engineering; Analytical chemistry; Environmental chemistry