Bioinspired SiO2/PDA/PTFE membrane with high corrosion-resistance for long-term efficient oil/water separation

Oil spills and oily wastewater from various industries caused severe harm to the environment and human life. Then the effective treatment of oily wastewater is extremely urgent. Superhydrophilicity/underwater superoleophobicity membranes are considered as a favorable choice for the separation of oily wastewater. In this work, inspired by mussel adhesive protein chemistry, the SiO2/PDA/PTFE membrane (SPP) with hydrophilic chemical components and multi-scale rough structures was prepared by the facile combination of dopamine self-polymerization and sol-gel strategy. The hydrophilic SiO2 nanoparticles (NPs) and polydopamine layer can be co-deposited on the membrane surface through Michael addition reaction, thus avoiding the problem of coating damage during oil/water separation. Moreover, the SiO2/PDA layer has hydrophilic groups and micro/nano rough structure, which makes the SPP membrane possess superhydrophilic and underwater superoleophobic properties. The properties of SPP membrane facilitate the formation of a hydration layer on the membrane surface, thus minimizing direct contact with oil droplets. During the experiment of oil/water separation, SPP membrane demonstrated excellent separation ability, the permeation flux of SPP membrane was measured to be 6183 and 4389 L m−2 h−1 for oil-water mixture and oil-in-water emulsion, respectively. The oil/water separation efficiency had also reached more than 99.7%. In addition, the SPP membrane exhibited brilliant chemical stability under harsh environments. It is worth mentioning that the SPP membrane showed superior cycling and anti-fouling performance in the separation process. These excellent performances demonstrate the great potential of SPP membranes in the industrial applications.