A novel mixed matrix polymeric membrane was prepared from polyethersulfone (PES) and self-produced polyaniline/iron(II, III) oxide (PANI/Fe3O4) nanoparticles by phase inversion method. The core-shell structured PANI/Fe3O4 nanoparticles were verified and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR). Three different amounts of nanoparticles were introduced into the casting solutions to obtain the optimum value. According to the performance test, the membrane with 0.1 wt% nanoparticles indicated the highest Cu(II) ion removal but the lowest pure water flux. This is caused by nanoparticles located in the superficial pores of the membrane during preparation i.e., surface pore blockage. Morphological analysis including field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) as well as membrane performance tests revealed that adsorption is the most possible separation mechanism by the membranes. For better investigation of the adsorption mechanism, several isotherm models such as Langmuir, Freundlich and Redlich-Peterson were tested. Based on the isothermal results, the Redlich-Peterson model offered superior fitness indicating relatively complex adsorption mechanism. The reusability of the nanocomposite membrane was confirmed for several sequential adsorption-desorption processes using EDTA as regenerator. (c) 2012 Elsevier B.V. All rights reserved.