Antifouling membranes modified via chitosan derivatives for efficient oil-water separation

Abstract

Surface segregation as a simple and efficient method for in situ membrane surface modification, has distinct advantages in constructing antifouling membranes. In this study, two chitosan derivatives, carboxymethyl chitosan (CMC) and chitosan quaternary ammonium salt (HACC), are selected as surface modifiers to fabricate antifouling poly (ether sulfone) (PES) membrane for oil-water filtration. The addition of CMC and HACC can regulate the phase inversion process to acquire membranes with high porosity. During the phase inversion process, CMC and HACC can in situ crosslink the polyvinylpyrrolidone (PVP) segregation agent by hydrogen bonds at the water-polymer interface, constructing a hydrophilic and underwater superoleophobic modification layer on the membrane surface. Specifically, the CMC-modified membrane exhibits enhanced water permeance from 339 to 635 Lm^-2h^-1bar^-1 and antifouling performance with 98% flux recovery and 7% total flux decline. Furthermore, the membrane shows satisfying long-term performance stability in industrial oily wastewater treatment with the permeance maintained above 400 Lm^-2h^-1bar^-1 within 10-hour continuous filtration. The study provides a facile strategy to in situ fabrication of oil-water separation membranes with excellent antifouling performance, which displays application potential in practical oily wastewater treatment.