The effects of addition of cationic cetyltrimethylammonium bromide (CTAB), non-ionic (Triton X-100) and anionic sodium dodecyl sulfate (SIDS) surfactants in organic phase for preparing the composite nanofiltration membranes were investigated. The interfacial polymerization technique was employed by applying trimesoyl chloride (TMC) and piperazine (PIP) as the reagents for the preparation of poly(piperazineamide) on a UF support. The obtained thin layer membranes were placed in oven for 2 min at 70 degrees C. Water permeation performance, salt rejection, membrane surface charge, chemical structure and membrane morphology including top surface and cross-section were investigated for characterization of the prepared membranes using IR-ATR, SEM, filtration and zeta potential measurement. The prepared membranes using SIDS showed higher flux compared to the other membranes. SEM surface images demonstrate some defects and cracks on the thin layer surface of the membrane prepared with SIDS. For membrane containing CTAB, the salt rejection increased in the order of Na2SO4 > NaCl > MgCl2 with variation around 50-90%. (C) 2009 Elsevier B.V. All rights reserved.