The viability of recovering chromium (III) was studied by polymer enhanced ultrafiltration (PEUF) and its application to tannery wastewater treatment. Four polymers with different functional group, molecular weight and acid-basic equilibrium were tested at 40 and 60 degrees C in order to investigate the complexation and decomplexation of chromium (III) ions on the polymer chains: polyvinyl alcohol (PVA), polyacrylic acid-co-maleic acid (PACM), polyethylenimine (PEI) and ethoxylated polyethylenimine (EPEI). The reversibility of the polymer metal binding was studied by operating in a dead-end PEUF system. The best chromium (III) rejections for both reactions were obtained by EPEI. The feasibility of recovering chromium (III) with EPEI was also studied in a cross-flow PEUF system. Chromium ions were complexed by EPEI chains at pH = 5 and decomplexed at pH = 1. Membrane fouling due to conformational variations of EPEI was observed at high ionic strengths. (C) 2009 Elsevier B.V. All rights reserved.