Fabrication of Ultrathin Two-Dimensional MOF Nanosheets with Specific Traps for Selective Uranium Capture

Efficient removal of uranium from uranium-containing wastewater is of paramount importance for uranium resources recovery and environmental protection. Herein, an ultrathin two-dimensional (2D) CB-MOF nanosheet featuring specific traps was elaborately constructed for uranium extraction. Benefiting from its size-specific traps and internally sufficient adsorption sites, CB-MOF nanosheets exhibited strong affinity and exceptional selectivity toward uranium, with an impressive Kd value of 3.85 × 105 mL/g. This value is several orders of magnitude higher than that of competing ions, even for the chemically analogous VO2+. The 2D material also demonstrated superior anti-interference capability in treating complex aqueous solutions, such as simulated groundwater and acidic uranium mine wastewater, with uranium removal efficiencies exceeding 96.52%. The adsorption mechanism was elucidated via X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and density functional theory calculations, which revealed that the size-specific traps and inner multipoint functional sites played a key role in uranium capture, and their synergistic effect led to the above excellent uranium extraction performance. This study not only presents a novel strategy for designing 2D MOF nanosheets with trap structures but also opens up new avenues for addressing the global challenge of selective and efficient uranium separation from diverse aqueous environments.