Continuous Electrochemical Desalination via a Viologen Redox Flow Reaction
Fuming Chen, Jian Wang, Qiang Ru, Su Htike Aung, Than Zaw Oo, Benli Chu
Abstract
Developing redox media as flow electrodes is a critical key in electrodialysis (ED) cells during the desalination process, enabling continuity, low cost and easy operation for freshwater production. Herein, we present viologen redox media as positive and negative flow electrodes in a continuous desalinated ED device. The viologen is reduced at the negative reservoir and oxidized at the positive side with blockage of ion exchange membranes, acting as a catalysis medium. The water product with 284 ppm can be extracted from the as-prepared 6000 ppm salt feed, and a salt removal efficiency of up to 95.3% is achieved. Cyclic voltammetry is performed to investigate the electrochemical behaviors of viologen. In addition, the desalination performance influence from the different current densities, cyclability, and various salt concentrations is further explored in detail. The current research will be significant to the further development of electrodialysis desalination technologies for freshwater production.