Chlorine-resistant and dual anti-biofouling reverse osmosis membranes with zwitterionic and quaternary ammonium copolymers via mussel-inspired one-step codeposition

Abstract

Reverse osmosis (RO) membrane technology encounters challenges such as membrane biofouling and oxidation during practical use, which significantly hinders its further development and application. To improve the chlorine and biofouling resistance of RO membrane, we suggest a method that modifies the mass ratios of zwitterionic and quaternary ammonium copolymers in the mussel-inspired coating layer. This method successfully controls the hydrophilicity and positive charge of the membrane surface, enhancing its overall performance. The plate counting results indicate that the bacterial killing efficiency of the blended modified TFC membrane (50:50) against E. coli and S. aureus is ≥98 %. Thanks to the combined effects of the anti-adhesion zwitterionic copolymer and the antibacterial quaternary ammonium copolymer, the blended modified TFC membrane (50:50) demonstrates superior anti-biofouling performance in dynamic biofouling tests. Furthermore, the desalination performance of the blending modified TFC membrane (50:50) remains stable after long-term exposure to 60,000 ppm·h of active chlorine, while the desalination performance of the pristine TFC membrane significantly declines. In conclusion, our advancements in chlorine-tolerant and anti-biofouling RO membranes could enhance the reliability of RO technology.