Synthesis and characterization of polyurethane-cellulose acetate blend membrane for chromium (VI) removal

•Synthesis of pre-polymer and chain extended polyurethane.•Blending of polyurethane with cellulose acetate to enhance film forming ability.•Permeation properties of blend membrane are investigated by Ultrafiltration process.•Rate of chromium (VI) ion rejection and water flux are improved. Blended membranes of polyurethane and cellulose acetate were prepared, characterized and investigated for their performance. Various ratios of cellulose acetate were employed to prepare four different blend membranes. The characteristics of both pure and blend membranes were investigated and results were compared to distinguish their properties. Functional group analysis was carried out by attenuated total reflectance Fourier transform infrared spectroscopy (ATR–FTIR) of pure and blend samples. Contact angle measurement and water content were evaluated to determine the membrane hydrophilicity. Moreover, the membrane morphology was studied by scanning electron microscopy (SEM). The membrane permeation properties and ability to reject chromium (VI) ions were tested at various pH and pressure by utilizing different salt concentrations.