Highly Efficient Uranium Capture via Crystalline Water Coordination Coupling with Cation Exchange and Surface Redox Reaction Mechanisms within an Open-Framework Vanadoborate

Abstract

Developing highly efficient adsorbents for uranium-contaminated wastewater treatment has aroused tremendous attention due to the radioactive feature and environmental hazards. Herein, the 3D vanadoborate framework SUT-6 constructed from (VO)12O6B18O36(OH)6 clusters bridged by ZnO4(H2O) is evaluated for uranium removal, with a UO2 2+ adsorption capacity of up to 347.7 mg/g under the optimal pH of 4.0. It exhibits high selectivity to UO2 2+ with the existence of various common interfering cations and anions. In addition, the adsorption efficiency of SUT-6 is above 92% after the third round of the adsorption−desorption process. Most importantly, SUT-6 retains great UO2 2+ adsorption performance in uranium-contaminated environmentally relevant water sources, including natural river water and groundwater. Comprehensive characterization techniques were employed to probe the uranium speciation and accurate atomic-scale position after adsorption, to determine the adsorption mechanism. Results show that SUT-6 is promising for UO2 2+ capture based on the unique crystalline water coordination coupling with cation exchange and surface redox chemistry mechanisms under complicated environmental water conditions. This work provides new insights into designing highly efficient uranium adsorbents for practical uranium capture.

Interaction between Uranyl Cations and Layered Double Hydroxide Nanoparticles: Implications for Nuclear Wastewater Management

“…Uranium (U) present in wastewaters produced via its mining, processing, and use in the nuclear fuel cycle is a significant environmental concern , with a range of potential ecotoxicological effects identified. , This includes the presence of U in the remediation of contaminated solutes produced during various processes associated with the nuclear fuel cycle, including U-mining, effluents from spent nuclear fuel reprocessing, nuclear fuel storage facilities, , U enrichment sites that are subject to decommissioning, , or cleanup procedures following the nuclear accidents. , To address these challenges, and especially when other radionuclides including transuranics such as plutonium and americium isotopes, and fission products including 90 Sr and 137 Cs may also be present, several studies have investigated U capture using various materials − including layered double hydroxides (LDHs) formed in situ − or prefabricated LDHs as adsorbents. ,− …”