Sulfonic nanohydrogelled surface-modified microporous polyvinylidene fluoride membrane with excellent antifouling performance for treating water-oil separation of kitchen wastewater

Kitchen wastewater containing high concentration of suspended solids, salt and oil is a comprehensive wastewater that requires urgent treatment. Organic fouling limits the use of membranes for treating kitchen wastewater. Herein, we propose a novel sulfonic nanohydrogel membrane with superhydrophilicity and underwater-superoleophobicity. A 32-nm-diameter sulfonic nanohydrogel Poly(SPP-co-MA-co-FLUORAL-P), developed by the polymerization technique in an aqueous medium, was grafted onto the polyvinylidene difluoride (PVDF) microfiltration membranes. The developed PVDF-g-Poly(SPP-co-MA-co-FLUORAL-P) membrane exhibited excellent antifouling properties for treating kitchen wastewater. The influence of organics (edible oil, surfactant , protein and humic acid) and salts on the membrane filtration was thoroughly investigated. The Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy techniques were used to confirm the successful surface modification. The experimental results revealed that the pure water flux was 2161 L m −2  h −1 . A high oil rejection rate was achieved when the fabricated membrane was used for treating the simulated kitchen wastewater (˃99.7%). The excellent antifouling properties of the membrane significantly improved the circulation stability of the simulated kitchen wastewater filtration. The recovery rate of permeation flux was up to 100%. The chemical oxygen demand removal rate of the real kitchen wastewater was 61% and the flux recovery rate arrived at 98%. The PVDF-g-Poly(SPP-co-MA-co-FLUORAL-P) membrane can be potentially used for treating kitchen wastewater.