Studies on sulfonated styrene acrylonitrile and cellulose acetate blend ultrafiltration membranes

Membranes are increasingly used in the chemical and bioprocess industries replacing more conventional separation techniques. Blending of various polymers has stimulated great interest in membrane science to improve the performance of membranes, such as hydrophilicity and flux and to reduce the fouling behavior. This paper deals with the preparation of flat-sheet asymmetric blend ultrafiltration (UF) membranes by solution casting, followed by a phase separation method. Sulfonated styrene acrylonitrile (SSAN) was selected as the hydrophilic polymer in the blend. The blend membranes were prepared with different compositions of CA and SSAN. The prepared membranes were characterized for their UF performances, such as pure water flux, water content, porosity, membrane hydraulic resistance, and morphology. The average pore size and porosity of the membranes were revealed by pore statistics and molecular weight cut-off (MWCO) studies using different molecular weight of proteins. Observations from scanning electron microscope provided qualitative evidence for the trends obtained for pore statistics and MWCO results. The membranes were also characterized for their separation performance with proteins and metal ion solutions. The rejection of proteins and metal ions was marginally decreased, whereas the permeate flux was radically improved. The polymer- enhanced UF technique has been shown to be a promising technique for removal of heavy metals in solution. In this study, the process has been investigated for removal of toxic heavy metals, such as Cu(II), Ni(II), Zn(II), and Cd(II), from synthetic wastewater solutions.