Chemically synthesized alkyl-substituted polyaniline/chitosan (sPANIs/Ch-HCl) composites were used as adsorbent materials for the removal of Cr (VI) from aqueous solutions. The effects of initial chromium concentration, temperature, pH and contact time parameters onto the adsorption of chromium ions from aqueous solutions were investigated. The data obtained from our investigations were well described by the Freundlich isotherm Cr (VI) adsorption. From the Dubinin Raduskevich equation, the adsorption of Cr (VI) ions onto the composite is mainly controlled by physical adsorption. The maximum removal percentages obtained were 90% for Cr (VI) by using poly(N-methylaniline)/chitosan composite. Chromium adsorption onto the composite was confirmed using FTIR and SEM/EDX analysis. (C) 2011 Elsevier B.V. All rights reserved.