Cellulose acetate-poly(ether sulfone) blend ultrafiltration membranes. II. Application studies

Ultrafiltration membranes are largely applied as macromolecular solutes and heavy-metal-ion separation from aqueous streams. Cellulose acetate and poly(ether sulfone) blend ultrafiltration membranes were prepared by the precipitation phase-inversion technique in 100/0, 95/5, 85/15, and 75/25% polymer blend compositions in the absence and presence of a polymeric additive, poly(ethylene glycol) 600, at different additive concentrations and were used for the rejection of proteins trypsin, pepsin, egg albumin, and bovine serum albumin; a maximum of 94% rejection was achieved. The toxic heavy metal ions copper, nickel, and cadmium from dilute aqueous solutions were subjected to rejection by the blend membranes by complexation of the ions with the water-soluble polymeric ligand, polyethyleneimine (PEI). Permeate flux studies of proteins and metal ions were performed simultaneously with the rejection experiments. The atomic absorption spectra results reveal maximum rejection for copper complex and a minimum rejection of about 60% for the cadmium complex. The rejection and permeate flux of the blend membranes were compared with those of pure cellulose acetate membranes. (C) 2004 Wiley Periodicals, Inc.