Synergistic strategy design of (malonamide-amidoxime) bifunctional branching network crosslinked membrane and application in uranium (VI) resource recovery

The efficient recovery of uranium resources from complex systems was of great significance to the sustainable development of nuclear energy and to prevent the potential effects of environmental radioactivity and chemical toxicity of uranium. Herein, we reported a novel highly crosslinked two-dimensional branched network poly (malonamide-amidoxime) difunctional membrane (MAFPM) using malonamide-based polymer as the skeleton and chitosan membrane with abundant surface groups as the substrate. By introducing bromoacetonitrile and hydroxylamine oxime, (malonamide-amidoxime) difunctional synergistic strategy was realized. As a result of the high polymer synergy strategy, MAFPM-2 showed remarkable adsorption capacity of 876.45 mg/g for uranium (VI), excellent uranium-selectivity of 93.46% and the Kd value for uranium (VI) was 2.79 × 106 mL/g. Through the cross-linking with chitosan membrane, the recycling ability of the material was improved, and the recovery rate was maintained at 82% after four adsorption cycles. In addition, combined with characterization and DFT calculation, the synergistic effect between functional groups was elucidated, the carbonyl of amines used additional sites to form a more stable five- coordinated of uranium (VI) with the oxime group. The finding of this study indicated that MAFPM-2 provided a promising approach for uranium (VI) resource recovery.