CHARACTERIZATION OF ULTRAFILTRATION MEMBRANES BY SIMULTANEOUS STREAMING POTENTIAL AND FLUX MEASUREMENTS

A new apparatus was developed where streaming potentials and permeate fluxes of membranes could be measured simultaneously. In this way the effect of addition of a protein, bovine serum albumin, on the potentia l and flux could also be studied. On addition of protein the calculate d zeta potential of the membrane changed so as to be close to the pote ntial of the protein at that pH. At very low or high pH, where the pro tein and the membrane had the same sign of charge, adsorption decrease d and the potential of the membrane did not change fully to that of th e protein. The point of zero charge of the protein-covered membrane wa s slightly higher than the isoelectric point of the protein.