Having performed experiments described in [1-3] the friction coefficients, f(ik), coupling coefficients, q(ik), and diffusion indexes for ions and water, ($) over bar D-i, have been computed in order to discuss the interactions on transport of acid (HCl) through anion exchange membranes. Two membranes were examined - diffusion dialysis Neosepta AFN-7 and standard grade Neosepta AM-1 (Tokuyama Corp.). The frictional interactions and coupling effects in AFN-7 membrane, the dual mode sorption, high diffusion coefficient, ($) over bar D-HCl and negative reflection coefficient, sigma, can be explained postulating the dual mechanism of transport : a simple diffusion of acid dissolved in internal water combined with a kind of facilitated transport of the "absorbed" acid.