Synergizing peroxymonosulfate-activated advanced oxidation processes with underwater superoleophobicity in composite membranes for enhanced anti-fouling in oily wastewater purification

Abstract

Underwater superoleophobic characteristics of the membranes have been developed to defeat fouling caused by organic solvents and oils with low viscosity and high volatility in oily wastewater treatment. However, the classic strategy is lacking in fighting for worse membranes caused by viscous/nonvolatile oils and soluble materials such as dyes and antibiotics in wastewater. Hence, a synergistic antifouling mechanism, combining hydrophilicity/low oil adhesive underwater superoleophobicity and advanced oxidation processes (AOPs), is proposed and implemented by CoFe₂O₄/Fe₂O₃ nanoparticles anchored on polyvinylidene fluoride/polyacrylic acid (PVDF/PAA) blend membranes against various foulants in wastewater. Briefly, the as-prepared composite membrane not only repels the oils and hydrophobic groups in dyes/antibiotics from adhering to the surface due to its low oil adhesive underwater superoleophobicity and hydrophilicity, but also it can effectively degrade the foulants on the surface and within the pore walls because of its excellent AOPs performances. Specially, after the separation of complex oil-in-water emulsion including soybean oil, methylene blue (MB), and levofloxacin (LEVO), the composite membrane bearing hydrophilicity/underwater superoleophobicity and excellent AOPs has a high flux recovery ratio of 95.4 ​± ​0.3 ​% and a low fouling resistance of 0.1 ​× ​10¹¹ ​m⁻¹. This innovative synergistic antifouling mechanism offers an outstanding anti-fouling membrane for the purification of complex wastewater containing various foulants.