A novel nanofiltration membrane prepared by interfacial polymerization of purposefully synthesized polyhexamethylene guanidine hydrochloride (PHGH) with antibacterial property and trimesoyl chloride (TMC) on polysulfone (PSf) ultrafiltration membrane was investigated. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM) and atomic force microscopy (AFM) were employed to characterize the chemical structures and morphologies of the active layers of obtained membranes. The effects of monomer concentrations, reaction time, curing temperature and time on filtration performance of the composite nanofiltration membranes were discussed. It was found that the membrane rejections to different salts followed the order of MgCl2> MgSO4> Na2SO4> NaCl. Dyes rejection results further showed the feasibility for the membranes to separate small organic molecules with a molecular weight cut-off (MWCO) of around 700 Da. Antibacterial experiments indicated that the newly prepared composite nanofiltration membrane had effective inhibition against Escherichia colt Furthermore, a 50 h fouling test using high concentration of bacteria solution also demonstrated an enhanced anti-biofouling performance of the composite nanofiltration membrane. (C) 2014 Elsevier B.V. All rights reserved.