CONCENTRATION OF SALTS IN THE PERMEATE DURING ULTRAFILTRATION IN THE PRESENCE OF POLYELECTROLYTES

A mathematical model is developed that describes an earlier discovered phenomenon of the metal ion concentration in the feeding solution in the course of ultrafiltration of a low-molecular-weight salt-polyelect rolyte mixture. The phenomenon is related to the spontaneous appearanc e of an electric field in the diffusion layer in front of the membrane as a result of the concentration polarization of the high-molecular-m ass polyelectrolyte not permeated through the membrane. On the basis o f the theory, a formula is derived for calculation of the logarithmic coefficient of concentration and the experimental data are treated for the NaCl, KCl, RbCl, and CaCl2 salts. The results show a good agreeme nt between the theory and experiment.