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.