Reduced Transport Numbers of PolysulfoneMembranes From The Initial Time EMF Measurements

Initial membrane potentials of polysulfone cation exchange membranes were measured with KCl, NaCl, LiCl CaCl2 and FeCl3 solutions by using Ag/AgCl electrodes. The measurements were carried out for KCl / unsupported polysulfone cation exchange membranes (SA3S) or polyester supported polysulfone cation exchange membranes ( SA3T) / KCl, NaCI, LiCI, CaCl2 and FeCl3 systems. The concentration of KCl, C1, was kept constant at 1.10-2 M in one cell; however the concentrations of KCl, NaCI, LiCl, CaCl2 and FeCl3, C2, in the other cell were changed from 1.10-4 M to 2.0 M. The Supported face of SA3T membrane was brought to equilubrium with the left- hand solution and then, the unsupported face of SA3T membrane was exposed to the right-hand solution. Transport number of K+, Na+, Li+, Ca+2, Fe+3 ions corresponding to the each of two surface layers of the membrane was evaluated from the initial time and the fifth minute emf measurements. The results were compared with between unsupported polysulfone cation exchange membranes and polyester supported polysulfone cation exchange membranes