MODEL FOR THE COMPETITIVE TRANSPORT OF IONS THROUGH ION-EXCHANGE MEMBRANES WITH A MODIFIED SURFACE

A mathematical model for the membrane with a modified surface is consi dered. The proposed model is based on the Nernst-Planck equations. Sur face modification is taken into account by introducing phenomenologica l conductivity coefficients. The competitive transport of two counteri ons is studied. It is shown that the modifying layer affects significa ntly the permselectivity at low current densities and does not affect the membrane permselectivity at the limiting current. These regulariti es result in the appearance of an extremum in the dependence of the ef fective transport numbers on the current density.