The role of the salt electrolyte on the electrical conductive properties of a polymeric bipolar membrane

We have studied the contribution of the salt electrolyte to the electrical conductive characteristics of a bipolar membrane. We present first a critic al analysis of previous theoretical approaches, and discuss the limits of v alidity. Experimental current-voltage curves of several commercial bipolar membranes in the low current density region are also shown. Special attenti on is paid to the measuring procedure and the data reproducibility. The eff ects of temperature, concentration of the salt electrolyte and flow rate ar e also considered. The comparison of theory and experiment shows the crucia l role of the salt ions on the electrical conductive properties of the memb rane, even when the water splitting phenomenon occurs. (C) 2001 Elsevier Sc ience B.V. All rights reserved.