Effects of alternating electric fields on transport through ion exchange membranes

Abstract

Transport of permitted and Donnas-forbidden ions as well as neutral solutes through ion exchange membranes have been investigated in continuous flow-through configurations in the presence and absence of an alternating electrical field (0.05–100 kHz, 0–40 V p-p). There is no discernible effect on the transport rate of forbidden ions and neutral solutes but very significant increases in steady state transmembrane transport occur for permitted ions. At least for cation exchangers, an increase in effective ion exchange capacity also appears to occur in the presence of the field. These effects are ascribed to the greater kinetic energy of the ions exposed to the alternating field and thus to the higher effective thermodynamic temperature the ions experience.