High performance polyester reverse osmosis desalination membrane with chlorine resistance

Chlorination is a common practice to prevent biofouling in municipal water supplies, wastewater reuse and seawater desalination. However, polyamide thin-film composite reverse osmosis membranes—the premier technology for desalination and clean-water production—structurally deteriorate when continually exposed to chlorine species. Here, we use layer-by-layer interfacial polymerization of 3,5-dihydroxybenzoic acid with trimesoyl chloride to fabricate a polyester thin-film composite reverse osmosis membrane that is chlorine-resistant in neutral and acidic conditions. Strong steric hindrance and an electron-withdrawing group effectively prevent direct aromatic chlorination, and residual OH groups capped with isophthaloyl dichloride preclude reaction with active chlorine. The poly(isophthalester) membrane exhibits high salt rejection (99.1 ± 0.2%) and water permeability (2.97 ± 0.13 l m−2 h−1 bar−1), even after demonstrating biofouling prevention with chlorine (50 mg l−1 of NaOCl for 15 min). We anticipate that our chlorine-resistant membrane will greatly advance reverse osmosis desalination as a sustainable technology to meet the global challenge of water supply. Reverse osmosis membranes are the primary technology used for desalination and wastewater recycling, but they are prone to biofouling and subsequent performance deterioration due to poor tolerance to disinfecting agents such as chlorine. Here a chlorine-resistant polyester reverse osmosis membrane is developed to prevent biofouling and increase the sustainability of desalination and wastewater reuse.