Ionic Liquid-Based Composite Thin-Films for Selective Ion Separations in Electrodialysis

The onset of climate change and rising global population has caused greater water scarcity, a considerable problem which threatens our world. The demand for fresh water is pushing a fast development of water purification technologies. Among these technologies, membrane-based water desalination processes are playing an interesting role in both academia and industry. Electrodialysis (ED) is an electro-membrane separation process aimed at water treatment through ion removal, which is achieved through the selective control and transport of ionic species. ED is a popular water treatment method; however, it is limited by membrane scaling, lack of ion selectivity, and high energy consumption for high salinity feeds. This study is focused on the synthesis of unique ionic liquid-based anion exchange membranes in order to obtain ion-selectivity in Electrodialysis (ED) systems through the addition of a divalent ion repulsion layer. Thin films of polymerizable ionic liquids were coated and cured on the anion exchange membranes in order to enhance ion selectivity in (ED) system. The membrane characteristics were studied through FTIR, SEM, AFM, contact angle measurement, and ED performance. Results suggest that while imidazolium coatings were incompatible with ED system due to rapid degradation, phosphonium coatings exhibited enhanced monovalent ion selectivity