Green preparation of quaternized vinylimidazole-based anion exchange membrane by photopolymerization

Abstract At present, most preparation processes of ion exchange membranes inevitably involve toxic solvents and complicated synthetic procedure. Herein, we reported a one-pot ultraviolet induced polymerization route to prepare quaternized imidazole-based anion exchange membranes. During the preparation processes, only environmentally friendly ethanol and water were used as solvents. The effects of mass ratio of quaternized imidazole monomer, crosslinker and vinylimidazole comonomer diluent on membrane structures and properties were carefully investigated to optimize the performance of anion exchange membrane. In optimized conditions, reliable mechanical properties as well as good electrochemical property could be achieved. The best-performing membrane showed a resistance of 1.86 Ω·cm2 (reaching the level of a normal homogeneous membrane) and desalination ratio as high as 99% (superior to the commercial anion exchange membrane Fuji type II (98%)). Besides, the reaction mass efficiency of all membranes was above 94%, indicating the high raw material utilization, low energy consumption and environmentally friendliness of the proposed synthetic route. This research would shed light on the development and commercialization of the green synthetic route for ion exchange membranes.