The adsorption of malachite green (MG) dye onto rambutan peel-based activated carbon (RPAC) was carried out in this work. The effects of different reaction parameters such as the initial MG concentration, contact time, solution temperature and initial pH on MG adsorption were investigated. MG adsorption uptake was found to increase with increase in initial concentration, contact time and solution temperature. The adsorption equilibrium data were best represented by the Freundlich model. Adsorption kinetic was found to follow the pseudo-second-order kinetic model. The mechanism of the adsorption process was determined from the intraparticle diffusion model. Boyd plot indicated that the MG adsorption on the RPAC was controlled by film diffusion. Thermodynamic parameters Delta G degrees, Delta H degrees, Delta S degrees and E-a were also determined. (C) 2011 Elsevier B.V. All rights reserved.