CHARACTERIZATION OF ULTRAFILTRATION MEMBRANES USING GEL-PERMEATION CHROMATOGRAPHY

A method has been developed to characterize the transport properties o f ultrafiltration membranes. A solution of polydisperse dextrane is em ployed and a steady-state sample of the feed and permeate is taken, us ing for the testing an ultrafiltration apparatus with cross-now of the feed over the membrane surface. Analysis of the amount of polymer in each stream and the determination of its molecular weight distribution by means of gel permeation chromatography permits a complete cut-off characterization of the membrane. Partial retention coefficients relat ed to a given molecular weight fraction taken from gel permeation chro matography make possible to determine the relationship molecular weigh t-retention coefficient.