MEMBRANE DIFFUSION-CONTROLLED KINETICS OF IONIC TRANSPORT

A computer algorithm based on the Nernst-Planck equation has been deve loped for digital simulation of ionic transport in an ion exchange sys tem with a membrane separating two electrolyte solutions. The Na+-H+ c ouple has been studied experimentally with a cation-exchange membrane to test the numerical algorithm. The optimum diffusion coefficients of the counter-ions are determined for the membrane diffusion controlled exchange rate. The measured external solution concentrations agree sa tisfactorily with the numerical results. This procedure allows the tre atment of unsteady state transport through membranes and avoids the nu merical instabilities which are frequently encountered in numerical me thods.