Bifunctional TiO2-Coated SSM for Efficient Emulsion Separation and Photocatalytic Degradation of Soluble Organic Pollutants

The oily wastewater containing complex organic pollutants poses a great threat to the environment and human beings. At present, the membrane used to treat oily wastewater has some problems, such as complicated preparation and serious membrane pollution. Superhydrophilic/underwater superoleophobic membranes overcome the problems of the surface of the membrane being easily polluted or even blocked by oil, so they have been widely studied by many researchers. In this work, we used an electrochemical deposition method to uniformly load titanium dioxide (TiO₂) nanoparticles onto pretreated stainless-steel mesh for efficient oil-in-water (O/W) emulsion separation (TiO₂@SSM). The membrane of TiO₂@SSM exhibited superior superhydrophilicity and underwater superoleophobicity, ensuring high O/W separation efficiency, reaching 99.8%, and fast water flux of up to 208.0 L·m^-2·h^-1 for various O/W emulsions. Meanwhile, the membrane possessed a desirable photocatalytic degradation property under visible light irradiation and a degradation efficiency of 98.1% for RhB pollutant. Specially, the as-prepared membrane had long-lasting robustness, sustainability, and recyclability through the cyclic experiments of emulsion separation and photocatalytic degradation. Our results provide a simple and universally applicable route to construct a multifunctional membrane for simultaneously achieving water purification in complex oily wastewater.