In situ synthesizing silver nanoparticels by bio-derived gallic acid to enhance antimicrobial performance of PVDF membrane

Modifying membranes with nanoparticles is a promising approach to mitigate biofouling in membrane preparation processes. However, high costs of the modification agents limit the practical applications of this approach. In this work, we developed a cost-effective and ecofriendly method to provide polyvinylidene fluoride membrane with a strong antimicrobial activity by loading silver nanoparticles (AgNPs). In this approach, gallic acid (GA) was used as a capturing and reducing agent to in situ synthesize AgNPs on membrane surface. The resulting AgNPs-functionalized membrane exhibited a 3.5-fold higher pure water flux and enhanced antifouling capacity compared to the control membrane. Specifically, AgNPs endowed the membrane a compelling antimicrobial activity on both Gram-positive and Gram-negative bacteria, evidenced by diffusion inhibition zone and bacterial proliferation test results. More importantly, pomegranate peel extracts rich in GA was effectively used in such a membrane functionalization approach. Taken together, this work demonstrates the robust in situ fabrication of antimicrobial AgNPs-functionalized membranes through bio-derived GA and provides a promising alternative for their potential practical applications.