REDUCING THE PROTEIN FOULING OF POLYSULFONE SURFACES AND POLYSULFONE ULTRAFILTRATION MEMBRANES - OPTIMIZATION OF THE TYPE OF PRESORBED LAYER

The mechanisms of whey-protein fouling of polysulfone ultrafiltration (UF) membranes were studied. The results of whey-protein adsorption at a nonporous polysulfone model surface were compared with permeate flux measurements of polysulfone UF membranes fouled by filtration of a whey-protein solution. The effect of presorbing the model surface and the membranes with anionic, non-ionic and cationic polymers and surfactants on the adsorption of whey proteins and the membrane flux decline was established. Protein adsorption was found to be a major cause of the observed decline in membrane flux. Especially non-ionic, hydrophilic polymers were found to minimize protein adsorption as well as to decrease the membrane resistance during UF, while the application of surfactants and ionic polymers was generally less successful. Some of the observed effects of surface presorption can be explained by considering physico-chemical interactions between the protein and the modified surface. © 1990.