To study the ion exchange kinetics of heavy metal ions on the organic-inorganic composite cation exchanger poly-o-toluidine Zr(IV) tungstate, NernstPlanck was computer simulated. Simulated numerical results for counter ions (Cu, Zn, Cd and Pb) of equal valence and four different ionic mobilities are presented to understand the ionic diffusion process. These results are based on the fractional attainment of equilibrium U(s), of the counter ions under study. The forward (M 2? -H ? ) and reverse (H ? -M 2? ) ion exchange processes are justified as the particle diffusion phenomenon. The self-diffusion coefficient (D o ), energy of activation (E a ), and entropy of activation (DS*) have also been estimated to understand the ion exchange process occurring over the surface of this cation exchanger and indicated that the ion exchange process is feasible and spontaneous. It is concluded that the difference in activation energies and entropy of activation may facilitate the separation of metal ions. The regeneration capability of this cation exchanger was also explained.