The aim of this study was to evaluate the performance of the micellar-enhanced ultrafiltration (MEUF) process for the simultaneous removal of aniline and nickel from the aqueous phase. A prepared polysulfone (PSf) membrane and two commercially available membranes (NP010 and UFX5) were used to investigate the effects of the molecular weight cut-off of the membranes on the performance of MEUF which highlighted the significance of the mean micelle size in this process. Increasing of sodium dodecyl sulfate (SOS) concentration and the addition of aniline and nickel into the solution would change the SDS micelle size. The best rejection of nickel and aniline, 97% and 70%, respectively, was achieved with NP010 membrane which has the smallest pore size (1 kDa). The results demonstrated that the rejection of nickel and aniline are influenced by the co-presence of them in solution. The presence of nickel ions in the solution increased the aniline rejection. Moreover, the presence of aniline molecules enhanced the nickel rejection. In the mixed surfactant solution (SDS-Brij 35) for the prepared PSf membrane, nickel rejection and permeate flux achieved over 90% and 100 kg/m(2) h, respectively at a pressure of 2.5 bar. (C) 2014 Elsevier B.V. All rights reserved.