Polymeric blend ultrafiltration membranes based on cellulose acetate and polysulfone were prepared by phase imersion technique in presence of different additive concentrations, polyvinylpyrrolidone and characterized in terms of compaction time, pure water flux (PWF), water content, membrane resistance and scanning electron microscopy(SEM). The blend membranes were subjected to separation of proteins and heavy metal ions using polyethylenimine as a complexing agent and the results were discussed. The molecular weight cut off of blend membranes was also reported. (c) 2005 Elsevier B.V. All rights reserved.