Alternating current enhanced deposition of a monovalent selective coating for anion exchange membranes with antifouling properties

In this work, a monovalent selective anion exchange membrane was prepared by a two-step modification process based on mussel inspired surface chemistry and amide condensation reactions. An alternating current electric field was employed to boost the homogeneity and stability of the coating. The membrane surface chemistry was investigated by attenuated total reflectance Fourier transform infrared spectroscopy; the surface roughness was analysed by atomic force microscopy and the hydrophilicity was evaluated by water contact angle measurement. Desalination experiments were conducted to evaluate the selectivity of the membrane for monovalent anions. The resulting membrane showed enhanced monovalent separation efficiency in comparison with the original membrane (17.33% and 4.90% SO42−/Cl−, respectively). The stability of the coating was successfully evaluated by the application of a reverse electric field in electrodialysis. The resulting membrane acquired an increased resistance to organic fouling. This work shows a facile avenue to obtain a stable monovalent selective anion exchange membrane with enhanced antifouling properties.