(665f) Development of Robust, Ion-Selective Polymeric Ionic Liquid Composites for Reduced Energy Consumption within Water Purification Via Electrodialytic Separations

The onset of climate change and rising global population has increased water stresses around the globe. This heightened demand for water drives researchers to develop improvements to water treatment and water recovery technologies. Among these technologies, membrane-based separations processes play a vital role for the future of water treatment as desalination and industrial wastewater recovery become increasingly important to ensure global water stability. Electrodialysis (ED) and Electrodeionization (EDI) are mature technologies for water treatment; however, its application has been limited by scaling, lack of ion selectivity, and high energy consumption for high salinity feeds. This study investigated the potential of polymeric ionic liquid-based composites within electrodialytic separation systems for improvements in both ion selectivity and energy consumption with ED and EDI. Materials and membranes were characterized through NMR, FTIR, SEM, AFM, contact angle measurement, EIS, and separation performance. Results suggest that while imidazolium coatings were incompatible with ED due to rapid degradation during water treatment, phosphonium-based polymer ionic liquid composites exhibited improvements to ion selectivity and specific energy consumption. This work demonstrates that modification of ion-exchange membranes with thin-film PIL coatings can exhibit enhanced ion selectivity with comparable separation efficiency to uncoated membrane, resulting in improved productivity for water treatment in various applications, such as industrial wastewater reuse, agriculture, and hydraulic fracturing.