Concentration polarization in electrodialysis

The limiting current density is determined by concentration-polarization effects at the membrane surface in the diluate containing compartment that in turn is determined by the diluate concentration, the compartment design, and the feed-flow velocity. Concentration polarization in electrodialysis is also the result of differences in the transport number of ions in the solution and in the membrane. The transport number of a counterion in an ion-exchange membrane is generally close to 1 and that of the co ion close to 0, while in the solution the transport numbers of anion and cations are not very different. 

B.A Cooke, Concentration polarization in electrodialysis-I. The electrometric measurement of interfacial concentration, Electrochim. Acta, 1961, 3, 307-317. 

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