Polyacrylonitrile nanofibrous membrane composited with zeolite imidazole skeleton-8 and silver nanoclusters for efficient antibacterial and emulsion separation.

Oily wastewater discharged by industrial development is an important factor causing water pollution. Membrane separation technology has the advantages of low cost, simple operation, and high efficiency in the treatment of oily wastewater. However, membrane materials are easily eroded by microorganisms during long-term storage or use, thereby resulting in reduced separation efficiency. Herein, a zeolite imidazole skeleton-8@silver nanocluster composite polyacrylonitrile (ZIF-8@AgNCs/PAN) nanofibrous membrane was fabricated by electrospinning and in situ growth technology. The surface chemistry, morphology, and wettability of the composite membranes were characterized. The carboxyl groups on the surface of hydrolyzed PAN nanofibers, which can be complexed with zinc ions (Zn2+), are utilized as growth sites for porous metal organic frameworks (ZIF-8). Meanwhile, AgNCs are loaded into ZIF-8 to achieve stable hybridization of ZIF-8@AgNCs and nanofibers. The loading quantity of ZIF-8@AgNCs, which can dominantly affect the surface roughness and the porosity of the membranes, is regulated by the feeding amount of AgNCs. The ZIF-8@AgNCs/PAN membrane achieves effective oil-water separation with high separation efficiency toward petroleum ether-in-water emulsion (98.6%) and permeability (62 456 ± 1343 Lm-2 h-1 bar-1). Furthermore, the ZIF-8@AgNCs/PAN membrane possesses high antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), which is beneficial for the long-term storage and use of the membrane.