Determination of the counter-ion transport number in an ion exchange membrane using the concentration cell method

The permselectivity of an ion-exchange polymer is one of the most important physicochemical characteristics leading to the evaluation of its performan ce. It constitutes one of the principal criterion for selecting this kind o f material for chemical or electrochemical applications. The classification of a set of membranes according to their permselectivity can be obtained f rom the co-ion or counter-ions transport number values. Usually, Hittorfs m ethod is the most widely used one for this kind of measurements, in spite o f the inherent defaults to its principle. We have shown that the Hittorf method can be advantageously substituted by the method of the concentration cell, initially applied to inert and unchar ged films. (C) 2001 Elsevier Science Ltd. All rights reserved.