Electrochemical characterization of polysulfone membranes with different valence salt solutions

Membrane potentials of polysulfonated cation-exchange (SA3S and SA3T) membranes for KCl, NaCl, LiCl, CaCl2 and FeCl3 solutions using Ag/AgCl electrodes were measured. The measurements were carried out for, KCl|SA3S or SA3T|MCl, (M:K, Na, Li, Cu and Fe) systems. The concentration of salt solution (KCl) was kept constant in one side of the cell, C1, at 1×10−2 M and was changed in the other side of the cell, C2, from 1×10−4 to 2 M. The alteration graphs were drawn in order to find the potential values of membranes for ln (C1/C2) ratio changes. Using the values, the effective fixed charge density in membrane (Cx), the average value of transport numbers (t±), and partition coefficients (K±) in a polysulfonated cation-exchange membrane for different valence ions were determined. Using the Donnan equation and the Teorrel–Meyer–Sievers theory, membrane diffusion potentials and Donnan potentials were calculated both theoretically and experimentally.