Ionic liquid redox flow desalination of seawater

The solubility feature of redox electrolyte is a key factor to influence the performance of salt removal in redox flow electrode capacitive deionization. Herein, a novel redox flow desalination using ionic liquid (IL) as the eco-friendly solvent is proposed, i.e., 1-ethyl-3-methylimidazolium acetate. The high salt removal rate of 4.82 μg·min−1·cm−2 was obtained at the current density of 11 mA·cm−2. The low energy consumption of 254.12 kJ·mol−1 was achievable in IL, compared with 466.3 kJ·mol−1 in aqueous solution and 317.86 kJ·mol−1 ethanol. In addition, a long-term test with 11 cycles was conducted, and the real seawater was desalinated to a freshwater standard in batch mode. This work is significant for development of low-energy consumption in redox flow desalination via the usage of novel ionic liquids as solvent.