Constructing membrane surface with synergistic passive antifouling and active antibacterial strategies through organic-inorganic composite modifier

Membrane fouling is a common bottleneck in the treatment of wastewater, seawater or brackish water containing bacteria and other living microorganisms. Simultaneously introducing passive antifouling strategies (fouling resistance and fouling release) and active antibacterial strategies (off-surface antibacterial and on-surface antibacterial) onto membrane surfaces seems a promising strategy. In the present study, we designed a new type of organic-inorganic composite modifier comprising organic polymer PHFBM-PMAA-PMTAC (poly [hexafluorobutyl methacrylate]-poly [methacrylic acid]-poly [(2-(methacryloyloxy) ethyl) trimethyl ammonium chloride]) and inorganic Ag nanoparticles (NPs) to introduce the active-passive integrated antifouling strategies through synergistic surface segregation. We found that the Ag NPs could promote the surface segregation of copolymer and in turn copolymer would promote the bulk dispersion of Ag NPs. The resulting membranes exhibited superior and persistent antifouling properties as well as antibacterial properties. In the separation of oil-in-water emulsion and yeast suspension, the flux decline of the membranes was merely 4.0%, while the flux recovery ratio was nearly 100%. Meanwhile, the membranes exhibited desired off-surface and on-surface antibacterial properties, in which the antibacterial efficiency for Escherichia coli was nearly 100% and the width of inhibition zone was 4 mm.