Two-Dimensional Ion-Imprinted Silica for Selective Uranium Extraction from Low-Level Radioactive Effluents
Quan Gan, Meiyun Xu, Qian Li, Sen Yang, Jia Yin, Daoben Hua
Abstract
The recovery of uranium from low-level radioactive effluents (LLRE) is of strategic significance for the sustainable development of nuclear energy. However, the high salinity, massive coexisting nuclides, and radioactivity of LLRE are the major challenges for selective uranium extraction. Herein, a two-dimensional U(VI)-imprinted strategy is developed for highly selective uranium extraction through one-step fabrication of a specific U(VI)-imprinted cavity on silica lamellar. Thanks to the two-dimensional structure of silica lamellar, the optimal adsorbent possesses a high specific surface area of 497.7 m2 g–1 and abundant imprinted cavities with a phosphate group. Thus, the adsorbent has an adsorption capacity of 224.2 mg g–1 at 298 K, which is higher than most of the U(VI)-imprinted adsorbents. As the temperature increases to 308 and 318 K, the adsorption capacity gradually increases to 253.8 and 274.0 mg g–1, respectively. In addition, due to the great affinity to uranium and stability of imprinted cavities, the adsorbent exhibits a good salt tolerance of adsorption and a high selectivity for uranium against other coexisting ions even after 6 adsorption–desorption cycles. This work provides an efficient strategy for designing selective U(VI) adsorbents for LLRE treatment, which is meaningful in environmental and energy fields.