Enhanced performance and antibacterial properties of amine-functionalized ZIF-8-decorated GO for ultrafiltration membrane

Abstract

Biofouling is an inevitable obstacle that impairs the overall performance of polymeric membranes used in water and wastewater treatment. This research focuses on the development of a novel nanocomposite membrane incorporating an antibacterial agent which has the potential to diminish membrane biofouling. An antibacterial agent, zeolitic imidazole framework-8 decorated with graphene oxide (ZGO), was functionalised with amino groups via direct post-modification method using ammonium hydroxide solution. The modified sample was then incorporated into polyethersulfone (PES) matrix at different weight loadings to produce ultrafiltration hollow fibre membranes by phase inversion method. The surface hydrophilicity and roughness of the membrane were improved with additional incorporation of ZGO–NH. The filtration results indicate that the permeation properties of the composite membranes were significantly improved compared to unmodified PES membranes. The water flux of the composite membranes increased with increasing ZGO–NH amount. The optimum value of ZGO–NH content is 1.0 wt%, in which the water flux reached the maximum value at 95.49 L/m2 h, 64.0% higher than that of neat PES membrane while maintaining BSA rejection of >95.0%. Moreover, the modified membranes also exhibited impressive antifouling properties with a flux recovery ratio (FRR) of 84.4% which is significantly higher than that of unmodified PES membranes (57.1%). The composite membrane possessed antibacterial capability against Escherichia coli and Staphylococcus aureus, having an antibacterial rate of 81.1% and 85.7%, respectively. Our proposed approaches show an excellent antibacterial ultrafiltration membrane to overcome biofouling issues via membrane modification.