In the current research, ABS-co-PEG nanofiltration membrane was prepared by solution casting technique using N, N dimethyl acetamide as solvent. The effect of PEG concentration as additive in the casting solution on membrane flux, salt rejection, phase inversion time, water content, membrane porosity, membrane tensile strength and fouling was studied. Also the effect of operating conditions such as feed concentration, pressure and temperature on membrane performance were also studied. It was found that increase of PEG content up to 6 %wt in the casting solution initially led to increase in flux and decrease of salt rejection in prepared membranes. The flux was decreased and salt rejection increased by more increase in PEG content from 6 to 10 %wt. In addition, presence of PEG in membrane structure caused to formation of more stable flux during filtration time against fouling. Increase of feed salt concentration caused to flux decreasing. The ABS/PEG membrane showed more stable flux against increase of feed concentration. Moreover, flux was increased by increase of operating pressure and feed temperature. The results also showed a clear trend towards higher values of tensile strength by increase of PEG content ratio.
