Design of poly (arylene ether nitrile)@SiO2 nanoparticles super-wetting membrane for the fast separation of oil-in-water emulsions fabricated through physical confinement effect and dopamine-assisted bio-inspired deposition

The super-wetting polymer-based membrane has displayed promising application in the oily wastewater purification because of its unique anti-fouling feature. However, the creep of micro-/nano- structure on surface of membrane and wettability attenuation under harsh conditions would lead to the decrease of separation flux and efficiency, which posed a huge challenge to the membrane technology . In this study, we prepared the super-hydrophilic and underwater super-oleophobic polymer composite membrane through the one-step biomimetic deposition of sodium alginate , dopamine, and SiO 2 nanoparticles onto the surface of poly (aryl ether nitrile) (PEN) membrane with wavy rough structure. Typically, the effect of physical confinement, dopamine with strong adhesion, and the co-deposition of polydopamine and sodium alginate coatings endowed the composite membrane with durable super-wetting property (water contact angle: 0° and underwater oil contact angle: 153°) and oil repellent behavior. Hence, when separating different surfactant-stabilized oil-in-water emulsions, as-prepared PEN composite membrane showed high separation flux of 762.81 ± 28.37 L·m −2 ·h −1 (847.5 ± 31.52 L·m −2 ·h −1 ·bar −1 ) and rejection ratio of 99.51 ± 0.16 %. Furthermore, the efficient separation performance and super-wetting feature of composite membrane could be retained even treating in the conditions of 4 M HCl/80 ℃ and 1 M NaOH/80 ℃, which exhibited potential application for purification of oily wastewater containing different oil/water emulsions under harsh environments.