Initial flux and rejection characteristics of partially permeable ultrafiltration membranes

✍ Scribed by A. G. Waters; A. G. Fane

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 446 KB
• Volume: 26
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1981.070260916

✦ Synopsis

Abstract

Solutions of bovine serum albumin (BSA) were ultrafiltered with and without stirring through membranes partially permeable to the solute, over a range of pH values. At the isoelectric point, flux was a minimum and rejection was a maximum. For all conditions, the flux for stirred ultrafiltration was greater than without stirring, as expected from conventional theory, and in contrast to recently reported “anomalous” behavior measured at the isoelectric point. Some evidence of unusual behavior at the isoelectric point was obtained when the flux of a freshly ultrafiltered solution of BSA was compared to that when the permeate and retentate were recombined, and when the retentate concentration was adjusted to the original concentration. For pH values other than the isoelectric point, the fluxes were similar for each set of experiments. At the isoelectric point, it was also found that flux was insensitive to changes in stirring speed. The unusual behavior at the isoelectric point is attributed to protein aggregation and precipitation causing loss of membrane permeability.