LIQUID POROSIMETRY TECHNIQUE FOR CORRELATING INTRINSIC PROTEIN SIEVING - APPLICATIONS IN ULTRAFILTRATION PROCESSES

The understanding of variation in sieving properties of membranes is o f great importance for the successful development of ultrafiltration a pplications. A Liquid porosimetry technique is presented to quantify t he sieving variation among several polyethersulfone ultrafiltration me mbranes. Observed sieving coefficients were measured with proper preca utions taken to control and minimize fouling. These data were translat ed to intrinsic sieving coefficients using a stagnant film model. The intrinsic membrane sieving coefficient correlated well with the liquid porosimetry data. This liquid porosimetry technique can distinguish b etween membranes of different molecular weight cut-off and is sensitiv e enough to capture slight changes in the sieving coefficient of varia nts of the same cut-off membrane. This technique has several attractiv e features: it is nondestructive, independent of the module configurat ion and relatively simple to perform. Two potential applications of th is technique are also examined: (1) quantification of the effect of me mbrane variation on high performance tangential flow filtration (HPTFF ) for protein separations and (2) development of a membrane integrity test to ensure batch-to-batch consistency. This technique has the pote ntial for use in membrane quality control, membrane selection, and val idation of industrial ultrafiltration processes.