FOULING REDUCTION IN POLY(ACRYLONITRILE-CO-ACRYLAMIDE) ULTRAFILTRATION MEMBRANES

Ultrafiltration membranes with similar pore sizes were prepared from a crylonitrile homopolymer and copolymers with increasing acrylamide con tent. The membranes containing acrylamide were more hydrophilic, had a smaller dispersion force component of the surface energy, and a small er negative zeta potential than those prepared from the homopolymer. T he effect of the differing surface chemistry of these membranes with s imilar pore sizes was examined by studying the ultrafiltration of bovi ne serum albumin (BSA) as a function of feed pH. The hydrophilic membr anes showed higher permeate fluxes and flux recoveries than the hydrop hobic membrane, in spite of their reduced repulsive electrostatic inte raction. With increasing pH, protein transmission increased markedly f or the acrylamide containing membranes whereas the transmission throug h the hydrophobic membrane remained low. These rejection data are expl ained by the combined effects of the increased hydrophilicity, decreas ed dispersive surface energy and reduced electrostatic repulsion of th e acrylamide containing membranes.