Multifunctional TiO₂-Based Superoleophobic/Superhydrophilic Coating for Oil-Water Separation and Oil Purification

Materials that possess distinguishable superwettability toward oil and water have aroused widespread attention for their application in oil-water separation. Among them, a superoleophobic/superhydrophilic material is considered as the ideal candidate because of its antioil-fouling and water-wetting behavior; however, the fabrication is a challenge and there has been insufficient attention given to multipurpose applications in treating intricate mixtures. Herein, for the first time, a multifunctional superoleophobic/superhydrophilic coating integrated with a photocatalysis property was fabricated by the combination of polarity component-enhanced fluorosurfactant and titanium dioxide (TiO₂) nanoparticles. The coating applied on stainless steel mesh preserves the ability to separate immiscible oil-water mixtures, whereas the coated cotton preserves the ability to separate both surfactant-stabilized oil-in-water and water-in-oil emulsions. Notably, benefiting from the photocatalysis property of titanium dioxide, the coating also can be used in liquid purification. Contaminated oil can be separated and purified by a separation-purification process, during which the oil-soluble contamination is degraded under ultraviolet (UV) irradiation. The multipurpose coating provides an alternative solution for oil-water remediations, which has prospects in intricate liquid treatment in industrial and domestic applications.