NEW TECHNIQUES FOR EVALUATION OF IONIC CONDUCTIVITY OF ION EXCHANGE MEMBRANES USED IN THE ELECTRODIALYSIS PROCESS

New techniques for the determination of ionic conductivity of acrylic ion exchange membranes, as well as the electrochemical system used are presented in this paper. The electrochemical cell used in electrochemical impedance spectroscopy (EIS) investigation consisted of two plan-parallel platinum disk electrodes, with the acrylic membrane investigated placed between the electrodes. This configuration is placed inside the disk of a digital precision micrometer, which is able to determine very precisely the membrane thickness during the plotting of the electrochemical impedance spectra. The electrochemical impedance spectroscopy measurements were carried out with a Voltalab 40 potentiostat. According to the data obtained from the Nyquist and Bode diagrams, knowing the real thickness of the membrane during the measurements, were calculated the values of ionic conductivity. The chemical stability of this type of membranes was investigated by Fourier transformed infrared spectroscopy.