Transport properties of electrodialysis membranes in the presence of arginine II. Competition between the electrotransport of organic and inorganic ions through a cation exchange membrane in an aqueous solution of arginine chlorhydrate and sodium chloride

Abstract

Electrotransport of ionic species, organic and inorganic, were examined for the same system as in the first part of this study. The CMV Selemion membrane was in contact with an aqueous solution containing both sodium chloride and arginine chlorhydrate. The concentrations ranged from 10 −3 to 10 −1 M and the pH was maintained at pH 7, that is, here the arginine molecule bears a positive charge. Using radiotracers, it was possible to measure the individual fluxes of sodium and arginine counter-ions and also those ofchloride co-ions crossing the membrane under a constant electric current. The experimental results were analysed taking into consideration the kinetics of ion transport. The transport numbers of each ion through the membrane, the ionic concentration in the boundary layer and the rate constant of ion transfer at the membrane–solution interface could be determined and allowed to explain the loss of permselectivity of the ion-exchange membrane in the presence of organic ions.