Study on Efficient Operating Conditions for Bipolar Membrane Electrodialysis Using Different Ion Species and Anion-Exchange Membranes.

To investigate efficient operating conditions for bipolar membrane electrodialysis (BMED), a comparison of current efficiency () and power intensity () was conducted using different anion-exchange membranes (AEMs) and salt solutions (NaCl and NaSO) as feed solutions in BMED. The results indicated that was higher and was lower for a commercial proton-blocking AEM (ACM) than for a standard AEM (ASE) when NaCl was used. This is because ASE has a higher water content than ACM, leading to greater H permeability, which reduces . Conversely, when NaSO was used, ASE exhibited higher and lower cell voltage () than ACM, resulting in lower for ASE. This is attributable to the fact that, with NaSO, the effect of was more significant than H permeability. These findings suggest that efficient operation can be achieved by selecting the appropriate combination of AEMs and salt solutions.