Zwitterionic Ion-Selective Membranes with Tunable Subnanometer Pores and Excellent Fouling Resistance
Samuel J. Lounder, Ayşe Asatekin
Abstract
Nanofiltration (NF) membranes are an energy-efficient, scalable technology for water treatment and reuse. However, they are prone to fouling and offer limited selectivity between ions, hampering their use in water recovery and reuse. This work utilizes scalable self-assembly of zwitterionic copolymers combined with a novel cross-linking approach to develop membranes distinguished by exceptional mono/divalent ion selectivity, tunable pore size, and complete resistance to irreversible fouling. Extended cross-linking reduces the pore size to ∼0.9 nm, the smallest pore size reported for self-assembled copolymer membranes to date. These membranes achieve >99.2% SO42– rejection and a Cl–/SO42– selectivity of 101, demonstrating their promise for energy-efficient sulfate removal and other water treatment applications.