Application of the two-film theory to the determination of mass transfer coefficients for bovine serum albumin on anion-exchange columns

The paper. describes a method of simultaneous determination of the external and the solid-phase mass-transfer coefficients from frontal analysis data. The protein flux to the solid particles is determined from the slope of th e breakthrough curve and the mass-transfer coefficients are determined by f itting the two-film model to the experimentally determined flux. The two-fi lm model is compared with two apparent overall driving force models: the ap parent overall mobile phase driving force model and the apparent overall so lid-phase driving force model. The experiments show that the apparent overa ll driving force models fail to describe the flux correctly and this is sub stantiated by the theory. Results obtained with bovine serum albumin on the anion-exchange media Q HyperD, Source, and Poros show that the external fi lm resistance is significant for Reynolds numbers less than one. The experi mental Sherwood numbers are lower than expected and their dependence on the Reynolds number are much higher than expected. (C) 1998 Elsevier Science B .V. All rights reserved.