화학공학소재연구정보센터
Journal of Membrane Science, Vol.531, 68-76, 2017
Novel regenerable antimicrobial nanocomposite membranes: Effect of silver loading and valence state
Silver as a broad spectrum antimicrobial agent has been widely studied as anti-biofouling coatings in membrane surface modifications. Incorporation of Ag in nano-zeolite grafted on the membrane surface was recently demonstrated to provide sustainable and regenerable antimicrobial activity. In this study, we examined two new methods of forming the Ag-zeolite based antimicrobial coating using polyvinyl alcohol (PVA) and polydopamine (PDA), respectively. Both methods achieved a wide range of Ag loading. Silver release and bacterial exposure experiments showed that increasing Ag-zeolite loading accelerated Ag release, which led to stronger antimicrobial activity, but did not significantly extend the antimicrobial lifetime of the membrane. Reduction of Ag+ to Ag(0), however, effectively stabilized Ag, reduced Ag release rate, and significantly prolonged the antimicrobial efficacy against bacterial growth on the membrane surface. All coatings strongly inhibited cell attachment and growth on the membrane surface despite the bacterial growth in the suspension, demonstrating the benefit of surface coating versus disinfection pretreatment of feed water. These results show the potential of polymer/Ag-zeolite nanocomposite coatings as versatile approach towards long lasting and regenerable antibiofouling activity in membrane systems. They also highlight the importance of implementing slow-release mechanism in high Ag-zeolite loading samples for efficient utilization of loaded Ag.