Strategies to increase ion selectivity in electrodialysis

• Theory for ion transport in multicomponent electrolytes electrodialysis. Selective removal of nitrate over chloride is observed. Strategies to increase selectivity are evaluated. Increasing the membrane thickness results an increased selectivity. Decreasing charge density We analyze selective anions electrodialysis (ED) from a mixture where all ions monovalent, both experimentally, and by modified theory. The theory makes use Nernst-Planck equation describe across ion-exchange membranes combination with affinity, which parameter that accounts preference materials adsorb one more than another. For N O 3 - C l anions, affinity was measured adsorption experiment, it found adsorbs anion-exchange (AEMs) . Faster relative batch-mode ED experiments well described theory, three types AEMs we tested. From analysis model, can derive between different be further by: i) difference ii) AEM thickness, iii) decrease AEM. last two strategies go against general understanding thin highly charged better ED. Our proposed follow rigorously our combined theoretical–experimental study.