A NEW APPROACH TO THE EVALUATION OF THE EFFECTS OF PROTEIN ADSORPTION ONTO A POLYSULFONE MEMBRANE

A simple but suitable interpretation of fouling due to protein adsorption onto ultrafiltration membranes, is to attribute it to a modification of the morphological structure of the membranes, namely a decrease in pore size, and to an increase in the hydrodynamic friction between solute molecules carried by the solvent flow and the pore walls. Evidence is obtained by evaluating the pore size and pore size distribution of a clean polysulfone membrane and of the same membrane adsorbed with bovine serum albumin solutions of different concentrations. The parameters (mean pore radius and standard deviation) of the normal pore size distribution are calculated by a method based on a pore flow model as described in a previous work [J. Membrane Sci., 61 (1991) 49 1. Once those parameters are obtained, their correctness is evaluated, using a predictive model including the parameters. The values of ultrafiltration fluxes and rejections calculated by this theoretical predictive model are compared with the experimental data obtained for the ultrafiltration of dextran solutions. A good agreement is verified, thus validating the theory of prevailing pore adsorption, the characterization method and the predictive transport model.