Loubna Firdaous

A mathematical model of multicomponent mass transfer in electro-dialysis

A mathematical model has been developed which describes the mass transfer across monovalent-ion-permselective membranes as used in an electro-dialysis cell. The mass transfer model is based on the Maxwell-Stefan transport equations. The latter are derived in the membrane phase with two unstirred layers on each side. Donnan equilibrium is used to describe the concentration and the potential discontinuity on the membrane-solution interface by means of sorption measurements. The combination of the mass transfer model and the equilibrium model enables the prediction of concentration and potential profiles across the electro-dialysis stack once the model parameters are available which are obtained from literature, separate experiments or existing correlations.