Investigation of Operating Conditions for High Current Efficiency in Acid and Alkali Production by Bipolar Membrane Electrodialysis

Abstract

　Bipolar membrane electrodialysis (BPMED) can simultaneously generate acid and alkali solutions. One of the issues for BPMED is low current efficiency for acid/alkali production due to proton leakage from anion exchange membranes (AEMs). In this study, BPMED was performed using different AEMs and salt solutions to investigate the effect of AEM structure and salt solution on current efficiency. When using NaCl as the salt solution, a higher current efficiency was obtained in BPMED using a proton-blocking AEM compared with the standard AEM, although little difference was observed between the two AEMs when using Na₂SO₄.