Effects of osmotic pressure and adsorption on ultrafiltration of ovalbumin

The influence of osmotic pressure and solute adsorption on permeate flux during ultrafiltration of a solute that forms a gel‐like layer on membrane surfaces was investigated. Ovalbumin solutions were ultrafiltrated using three different kinds of membranes, polyolefine, polysullfone, and polyacrylonitrile. Flux data were analyzed by three conventional models: gel polarization, osmotic pressure, and resistance in series. The experimental data were in conflict with all conventional models. Data analysis suggested that the main factors which influence permeate flux decline were osmotic pressure increase at the membrane surface and resistance caused by solute adsorption. A new model, which takes into account both osmotic pressure and resistance due to solute adsorption, is proposed. Permeate flux declines observed in the experiments fit this model quite precisely. The gel layer that forms on the membrane surface has little influence on permeate flux and can be neglected.