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

Abstract

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.

Electrocatalytic Removal of Low-Concentration Uranium Using TiO2 Nanotube Arrays/Ti Mesh Electrodes

“…This was attributed to the outstanding electrocatalytic performance of the A-TNTAs/Ti mesh electrode and further demonstrated that the A-TNTAs/Ti mesh electrode could significantly reduce the energy consumption of U­(VI) removal. In addition, the energy consumption of electroreduction methods using the A-TNTAs/Ti mesh electrode was much lower than that of some other U­(VI) electrochemical removal methods. , …”

“…In addition, the energy consumption of electroreduction methods using the A-TNTAs/Ti mesh electrode was much lower than that of some other U(VI) electrochemical removal methods. 22,23 One other challenge of U(VI) removal using the electrochemical method is the low removal efficiency in the presence of low concentrations of U(VI). In the previous study, the electrochemical removal efficiency of U(VI) using the Ti plate and the UO 2 /Ti electrodes significantly decreased when the initial U(VI) concentration was lower than 0.5 μM at the potential of −0.6 V. 14 However, when the A-TNTAs/Ti mesh electrode was used for the electroremoval of low-concentration U(VI) (0.15−0.5 μM), the U(VI) concentration decreased rapidly and reached the detection limit (0.0042 μM) within 30 min even at a higher reduction potential (−0.4 V) (Figure 2D).…”

Electrochemical Techniques for Uranium Extraction from Water

“…For example, carbonate-containing systems exhibited >98% mass separation compared to <60% when other ions were present, e.g., Fe, Mn, Ni, and Cr [89]. Electrodeposition can also be photochemically assisted [91]. Yan et al,…”

Advanced Photocatalytic Uranium Extraction Strategies: Progress, Challenges, and Prospects

“…Unlike seawater and groundwater, the composition of actual uranium mining wastewater is very complex. It often contains various metal salts, organic matter, and microorganisms [ 114 , 115 ]. Although some advanced photocatalysts indicated good selectivity for the photocatalytic reduction in U(VI) in the presence of multiple ions and organic compounds, the concentrations of interfering ions and organic compounds in the simulated uranium-containing wastewater used in the laboratory are at the milligram level.…”