TiO2 Coated Polypropylene Membrane by Atomic Layer Deposition for Oil–Water Mixture Separation

Polypropylene (PP) membrane has been widely used in water purification and other fields owing to special pore structure, excellent mechanical properties and resistance to acids, alkalis and organic solvents. However, it is difficult for PP to introduce the hydrophilic chemical compositions for oil–water separation. Herein, superhydrophilic and underwater superoleophobic PP membranes were prepared by ALD for efficient gravity-driven oil–water separation. Owing to synergistic effect, oil contact angle of TiO 2 coated PP membrane under water can reach above 150°. Hence, TiO 2 coated PP membrane has great oil-repelling performance. Because of the superwetting property, TiO 2 coated PP membrane can easily separate oil–water mixture and have high separation efficiency (more than 95%). The outstanding recyclability and mechanical stability of TiO 2 coated PP membrane suggest the promising potential application in practical oil–water separation.