Bioinspired surface engineering of amidoxime functionalized polyvinylidene fluoride membrane for efficient uranium extraction from seawater and wastewater

Amidoxime functionalized polyvinylidene fluoride membrane (PVDF-AO-4). Efficient uranium (VI) extraction from seawater (UES) and wastewater is crucial for environmental remediation and nuclear power generation. Herein, a novel amidoxime functionalized polyvinylidene fluoride (PVDF-AO-4) membrane constructed through reaction of amoximated 2-diaminomaleonitrile (DAMN-AO) with Tannic acid of the Tannic acid (TA)-3-aminopropyltriethoxysilane (APTES) coating (TA-APTES coating) is designed via surface engineering technology. Introducing the amidoxime group with abundant multi-affinity sites endows PVDF-AO-4 with excellent adsorption capacity (q m = 175.8 mg/g) and selectivity for U(VI). Meanwhile, the PVDF-AO-4 exhibits outstanding recyclability, antifouling capabilities, high flux recovery rate (FRR) of over 90 % and low flux decline rate (FDR) of under 5 % after five cycles in the dynamic adsorption and great elution efficiency (nearly 80 %) after 10 cycles. PVDF-AO-4 can effectively capture 9.84 mg/g U(VI) in 3 weeks period from natural seawater. The membrane material designed in this work can be used for efficient, selective of uranium from seawater and wastewater.