THE FINE-STRUCTURE OF ULTRAFILTRATION MEMBRANES .2. PROTEIN FOULED MEMBRANES

Ultrafiltration experiments have shown that the quantity of protein adsorbed during filtration is dependent upon the membrane material. The specific resistance also varies between membrane types. Transmission electron microscopy (TEM) has been used to explain some of these differences. A number of TEM techniques have been used to examine protein fouled ultrafiltration membranes. Immunochemical staining has been successfully applied to membranes to locate the position of protein foulants at the separating surface and within the membrane matrix. It has been shown that as well as forming a thick fouling layer at the membrane surface protein foulants also pass into the membrane matrix. Examination of replicas of protein fouled membranes after freeze-fracture and deep-etching have shown differences in the nature of the protein layer at the separating surface of different membrane types. These have been linked to changes in membrane resistance due to protein adsorption.