Electrochemical Desalination Using Bi/BiOCl Electrodialysis Cells

The construction of new types of electrodialysis (ED) cells composed of Bi and BiOCl electrodes were investigated to achieve more cost-effective desalination using ED. By using the oxidation of Bi to BiOCl and the reduction of BiOCl to Bi as the anode and cathode reactions, respectively, the Bi/BiOCl ED cells decreased the equilibrium cell voltage to 0 V. As a result, the operating voltage of the Bi/BiOCl ED cells could be significantly lowered compared with the current ED cells. Two-compartment and three-compartment ED cells were constructed and their configurations and operating principles were explained in detail. The electrochemical and desalination performances of these cells containing different electrolytes were analyzed to examine the effects of the cell configuration and pH of the electrolytes on the operating voltage as well as Cl- and Na+ removal efficiencies. The results and discussion provided in this study will enable further development of Bi/BiOCl ED cells for use in desalination, wastewater treatment, and Cl- removal applications.