Zwitterionic-enhanced hyperbranched polysiloxane membrane with advanced anti-crude oil fouling for high-efficient...

Membrane fouling, attributed to the adhesion of oil droplets, presents a significant challenge to membrane separation technology. The hydrophilic surface modification of polymer membranes has been proven as an effective antifouling strategy. Here, a novel zwitterionic hyperbranched polysiloxane modificated membrane (ZHBPSi@PDA@M) was synthesized through oxidative self-polymerization to form the polydopamine (PDA) adhesion layer, Michael addition, and ring-opening reaction. The surface of ZHBPSi@PDA@M achieved the superhydrophilic modification, acquiring an underwater oil contact angle of 158.6°. Furthermore, the membrane had a high water permeance of 13,924 L m^-2 h^-1 bar^-1, representing a 29-fold increase compared to the nascent membrane, and achieved excellent separation of various oil-in-water emulsions, with permeance and rejection efficiency of 5534 L m^-2 h^-1 bar^-1 and 99.9 %, respectively. Additionally, the ZHBPSi@PDA@M not only achieved excellent acid-base stability, but also possessed good self-cleaning and anti-fouling properties. Moreover, the composite membrane effectively separated crude oil emulsions, achieving a permeance of 3986 L m^-2 h^-1 bar^-1 and a separation efficiency of 98.3 %, thereby offering a novel approach for the treatment of high-viscosity oil-containing wastewater.