The adsorption behaviour of amorphous aluminium oxide was studied with respect to Cr(VI) in order to consider its application to purify electroplating wastewaters. A batch method was employed using Cr(VI) concentrations ranged from 10 to 200 mg/l. The Langmuir model was found to describe the adsorption process well, offering a maximum adsorption capacity of 78.1 mg/g. The effect of ionic strength (0-0.1 M KNO3), pH (3-9) and competitive solutes (molar ratio [Cr(VI)]/[SO42-] = 1 and 100) on the retention process was evaluated. Cr(VI) adsorption on amorphous aluminium oxide appeared to be dependent on ionic strength with a more pronounced effect in acid conditions. Conversely, adsorption was not affected by pH in acid medium, but decreased when pH sifted to alkaline values. The presence of SO42- greatly reduced Cr(VI) removal across the entire pH range when both solutes were present in similar concentrations. Amorphous aluminium oxide also showed a high adsorption capacity when used in the purification of Cr(VI) electroplating wastewaters. The adsorbent doses required to attain more than 90% of Cr(VI) removal varied between 1 and 5 g/l depending on Cr(VI) concentration in wastewaters. (c) 2006 Elsevier B.V. All rights reserved.