Internal surface coverage of protein in membranes during the branes for long-term ultrafiltration (10). Generally it has initial phase of ultrafiltration was analyzed. Bovine serum albumin been found that protein deposition, on the order of 0.5 to (BSA), in solutions of pH 5 and 7 with 0.05 and 0.15 M NaCl, 200 mg/cm 2 , can adsorb on the membrane over a long time were ultrafiltered with 100,000-MWCO polysulfone membranes. (approximately 24 h) (8). This large discrepancy may be Mass uptake of the membranes was determined using electron due to assumptions of nominal surface area being equivalent paramagnetic resonance spectroscopy for separate membranes for to the adsorption area and to error in protein measurement.
fractions of an hour for up to 4 h. The resulting data were com-
An extensive study that considered the entire membrane area pared with models for surface coverage. The results showed a indicated that near-monolayer adsorption (0.5 mg/cm 2 ) was significant amount of protein loading exists in a very short time of exposure during ultrafiltration. The amount of material found obtained for bovine serum albumin (BSA) on polyether sulin this period was not a function of solution properties; however, fone membranes during long-term static adsorption (8).
solution properties did affect the resistance per mass for adsorbed
While studies have concentrated on long-term protein adspecies when the pH was near the isoelectric point of BSA. The sorption studies, only limited research has considered initial modeling comparison implied that the entrained solute from pH adsorption behavior (9)(10)(11). Initial studies and understand-7 appeared to behave as though it was lodged in the ultrathin skin ing the dependency of the solute interactions as a function area of the membrane. Solute in the membrane at pH 5 and low of solution properties can provide information on the initial ionic strength appeared to be lodged and adsorbed throughout the steps in the fouling process. However, difficulties in measurmembrane substructure.