Experiments were carried out to remove brilliant green dye by adsorption technique using a novel adsorbent (activated carbon prepared from acorn). The prepared adsorbent was characterized by BET surface area measurement, FTIR, SEM and elemental analysis. Various parameters such as initial dye concentration, adsorbent dose, initial pH and temperature were studied to observe their effects on the dye adsorption process. At optimum values of the above mentioned parameters, more than 90% removal efficiency was obtained within 30 min at adsorbent dose of 2 g/100 mL for initial dye concentration of 25 mg/L The percentage of dye removal remains almost constant within the pH range of around 6-10. The adsorption of dye was found to follow a pseudo-second-order rate equation. Intra particle diffusion model was studied in order to determine the rate limiting step of the adsorption process. Langmuir isotherm model was fitted the best for the adsorption system with an adsorption capacity of 2.11 mg/g of adsorbent. The present adsorbent may be considered as an alternative adsorbent for the better performance of the brilliant green dye removal from its aqueous medium. (C) 2011 Elsevier B.V. All rights reserved.