Fabrication of CFOx-PVDF catalytic membrane for removal of dyes in water and its mechanism

In this work, CoFe2O4 (CFO)−PVDF catalytic membrane was fabricated by coupling CFO into PVDF membrane. It can activate peroxomonosulfate (PMS) to oxidize contaminants. Therefore, the catalytic membrane can realize filtration and catalytic oxidation of dyes simultaneously. The single rejection rate of the CFO2 −PVDF membrane is about 70% and catalysis alone can remove 62.37% AR18 within 110 min. In comparison with filtration and catalytic oxidation separately, the removal rate of the catalytic membrane has a visible increase which can reach 100% within 70 min. The mechanism reveals that hydroxyl radical (·OH), sulfate radical (SO4·−) and 1O2 nonradical played about 13% parts, 27% parts and 60% parts in catalytic oxidation of dyes, respectively. The mechanism includes both radical and nonradical oxidation. The catalytic membrane has a good application for different type of dyes. The removal rate can still maintain at 86% after reused for five times since the catalyst CFO can renew from Co3+ to Co2+ through self recovery. Furthermore, the results confirm that the catalytic membrane has a good anti-fouling ability and low metal ions leaching risk.