The electrodialytic method with ion exchange membranes has been mainly used as the concentrating operation or the desalting operation of brackish water. As yet, an agreed view about ion transfer within the electrodialytic equipment has not been given. As one of the fundamental researches, therefore, the authors investigated the influence of concentration of feed solution, current density, flow velocity, electrolyte and temperature to the ion transfer in electrodialysis.
The measurement of some operating factors on the ion transfer was carried out for one pass of solution through the electrodialytic equipment with ion exchange membranes and without spacers. From this experiment, it was found that the contribution of the concentration difference between the concentrated solution and the desalted solution to the mass flux caused by the diffusion was negligible as compared with the contribution by the current density; namely, the mass flux was proportional to the current density, and the current transfer coefficient was shown by Eq.(8). In addition, this relation was valid even when the concentration of feed solution and the electrolyte in the electrodialytic equipment were changed.
About the effect of temperature, it was found that the mass flux of ion transfer could be increased by lowering the temperature during the electrodialysis.