Membrane fouling such as that caused by proteins in the feed solution adversely affects membrane separation performance and typically occurs either on the external membrane surface (cake formation) or within the internal membrane structure (pore plugging).  Despite much work over the years, comprehensive understanding of such fouling is still lacking because, in part, detection of fouling onset is still problematic.  Hence, the objective of this study is to clearly identify and contrast the conditions under which the real-time techniques of flux decline and ultrasonic reflectometry (UR) are best suited for monitoring the onset of protein fouling.  In addition, information from these techniques is compared with that obtained from post-mortem characterization including gravimetric measurements, protein bioassays, and low-magnification light microscopy.  Experiments utilized PES ultrafiltration (UF) membranes, and were conducted in a flat-sheet membrane separation module at cross-flow velocities of 7 cms<sup>-1</sup> and a constant transmembrane pressure of 0.34 MPa.  Membranes were initially exposed to ultrapure water for 24 h under pressure to allow complete membrane compaction.  A commercial protein, bovine serum albumin (BSA), was then introduced at different concentrations (0.5 – 50 g/L) to resolve fouling kinetics in a reasonable time frame.  Fouling generally included two distinct phases: (1) gel formation/protein adsorption (~5-30 min) and (2) protein deposition (&gt; ~30-min long).  Based upon the extensive results amassed from this study, the relationships between specific operating conditions and the respective UR and flux responses as well as their correlation with post-mortem metrics will be detailed and a comparison of the respective technique merits provided.

Comparison of real-time and post-mortem techniques for detection of protein fouling

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.