Effects of the surface layer structure of the heterogeneous ion-exchange membranes on their impedance

Experimental details of measuring the impedance of heterogeneous membranes by the contact method with graphite electrodes in an aqueous medium were considered. It was shown that the inductive and capacitive components of the cell impedance lead to overestimation of the ionic resistance of heterogeneous and homogeneous membranes by 9% and 27%, respectively. Considering the physicochemical structure of heterogeneous membranes and proceeding from the Randles circuit, an equivalent electrical circuit capable of correct impedance description for heterogeneous membranes was proposed. The pressure effect on the membrane impedance was studied. An increase in the pressure on the electrodes to 2 MPa was shown to result in a considerable increase in the polarization resistance of heterogeneous membranes and decrease in the ionic resistance. (C) 2016 Published by Elsevier B.V.