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

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.