Tangential-Flow Filtration for Virus Capture

Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, Colorado 80523-1370 

Ultrafiltration (UF) uses membranes with pore sizes ranging from 10 to 1000 A (0.1 pm). Consequently, large-pore UF membranes will have a similar pore size to smaU-pore MF membranes. The first UF membranes were prepared by Bechhold (1907) from colloidan. By the mid-1920s colloidan UF membranes were available for laboratory use. However, industrial use of UF membranes did not occur till the 1960s after the development of high-flux reverse osmosis (RO) membranes (Loeb and Sourirajan, 1963). Today, ultrafiltration is frequently used in the biotechnology industry for protein concentration and buffer exchange (diafiltration). 

Advanced Membrane Technology and Applications. Edited by Norman N. Li, Anthony G. Fane, W. S. Winston Ho, and T. Matsuuia Copyright 2008 John Wiley Sons, Inc. 

Tangential-flow filtration is typically operated in one of two modes concentration or diafiltration (see Fig. 20.2). For microfiltration, in the concentration mode, the product of interest usually passes through the pores of the membrane and is collected in the permeate. However, since MF membranes are nonselective, flie concentration of the product of interest will be the same in the retentate and permeate streams. 

Recovery of the solute of interest may be maximized by operating in diafiltration mode (see Fig. 20.2). Here diluent (free of particulate matter) is added to the feed reservoir at the 

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