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To remove nitrate and phosphate from sewage efficiently, current membranes need improved permselectivity, antifouling, and antibacterial properties. Herein, a new hybrid membrane modified with quaternary ammonium and silanol groups was fabricated by doping siloxane quaternary ammonium loaded activated carbon (SiQA) onto poly­(vinylidene fluoride) (PVDF). The hybrid membranes had surface morphology, porosity, membrane pore sizes, and water fluxes typical of ultrafiltration membranes. At a secondary sewage effluent flux of 35 LMH, the permeate nitrate and total phosphorus concentrations were <1 mg-N L–1 and <0.2 mg-P L–1, respectively. Superior removal selectivity of nitrate and phosphate was attributable to the introduced positively charged quaternary ammonium groups. Improved hydrophilicity from silanols reduced irreversible membrane fouling by 67% compared to a nondoped membrane. The quaternary ammonium groups also increased antibacterial activity. The antifouling and antibacterial hybrid membrane overcomes the permeability–selectivity trade-off and may be applicable in advanced sewage treatment.

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