Sharp rise in resistance of ion exchange membranes in low concentration NaCl solution
By Mir, Fasil Qayoom; Shukla, Anupam
Published in Journal of the Taiwan Institute of Chemical Engineers
2017
Abstract
Abstract Using a modified impedance measurement technique, ohmic resistance of commercial ion exchange membranes (Selemion {CMV} and {AMV} as well as Neosepta {CMX} and AMX) was measured in low concentration aqueous NaCl solutions. The ohmic resistance increased by an order of magnitude as the NaCl concentration was reduced from 0.5 M to 0.017 M Resistance of cation exchange membranes increased more than the anion exchange membranes. Resistance increased monotonically with a decrease in the NaCl concentration and the variation of resistance could be explained very well using a model based on the Kohlrausch law of conductivity. The model also provided value of the tortuosity for the membranes. Tortuosity of the membranes was between 3.4 and 4.5.