The Boundary-layer Resistance Model for Unstirred Ultrafiltration. a New Approach*

The possibility to analyse concentration polarization phenomena during unstirred dead-end ultrafiltration by the boundary layer resistance theory has been shown by Nakao et al. [ 1). Experimental data on the ultrafiltration of BSA at pH 7.4, at various concentrations and pressures, were analysed by this model and by a new version of the model in this paper. Instead of the assumption of the cake filtration theory, the new version of the model uses the unsteady state equation for solute mass transport to predict flux data by computer simulations. This approach requires no assumptions concerning the concentration at the membrane, the concentration profile or the specific resistance of the boundary layer. The computer simulations agree very well with the experimental data. Many agreements with Nakao’s analyses are confirmed and some new data on the concentration polarization phenomena are obtained.