The adsorption of malachite green (MG) from aqueous solution by two different adsorbents (CZn5, PETNa8) were studied. Adsorbents were prepared from pine sawdust and polyethyleneterephatalate (PET) by chemical activation with ZnCl2 and NaOH, respectively. The adsorption was carried out in a batch system as a function of dye concentration, pH and contact time. Both adsorbents were found to be very effective in removing the dye at high concentration with adsorption percentage in the order of CZn5 > PETNa8. The pH of dye solution in the range of 6-10, was found favorable for the removal of malachite green by using the two adsorbents at high concentrations. Equilibrium times were 120 and 90 min for CZN5 and PETNa8, respectively. Kinetics of removal MG was studied using Lagergren equation and diffusion phenomena was analyzed using Weber and Morris intraparticle diffusion plots. It was also showed that the adsorption isotherm followed Langmuir model. (c) 2005 Elsevier B.V. All rights reserved.