Modeling Transport Asymmetry in Bilayered Ion-Exchange Membranes Interacting with Surface-Active Organic Substances

A model is suggested for the electrical mass transfer in bilayered ion-exchange membranes, which accounts for the layers' structure. The concentration polarization in a bilayered system is analyzed and the extreme concentration variations at the boundary between layers with different selectivities are determined. It is shown that the current characteristics and the diffusion penetrability can go asymmetric following a change in the orientation of a bilayered membrane with respect to the ion flow. The asymmetry of an integral diffusion penetrability coefficient is determined quantitatively for ion-exchange membranes modified with surface-active organic substances. It is shown that the proposed approach is adequate for describing transport phenomena in anisotropic membranes with stable layer characteristics.