SIMULATION OF THE TRANSPORT OF IONS AGAINST THEIR CONCENTRATION GRADIENT ACROSS CHARGED MEMBRANES

In a multi-ionic system, changes in ion concentration in two cells containing strong-and weak-acid ion-exchange membranes were simulated as a function of time, to obtain the flux of each ion in the system from only the charge density and ion mobility in the membrane and the ion concentrations in the two cells. This enables a determination of how the concentrations of the other ions change if one ion is transported against its concentration gradient. From this, the mechanism of uphill ion transport across ion-exchange membranes is clarified. These phenomena are confirmed experimentally using cation-exchange and poly(vinyl alcohol) membranes.