This study was aimed at the adsorption of Brilliant Green (SG) dye on naturally existing red clay (RC) through batch adsorption experiment. Adsorbent characterization showed Brunauer-Emmett-Teller surface area 100.28 m(2)/g, pore volume 0.88 cm(3)/g, and pore diameter 148.2 angstrom. Batch studies were carried out to investigate the effect of experimental factors such as pH (2-10), particle size (58-150 mu m), adsorbent dose (0.3-1.5 g/L), contact time (5-1500 min), initial dye concentration (20-100 mg/L), and temperature (25-65 degrees C) on the adsorption of BG dye. Langmuir (R-2 = 0.993), Freundlich (R-2 = 0.997), Hansley (R-2 = 0.997) and Redlich-Peterson (R-2 = 0.999) isotherms were fitted to describe the equilibrium of BG adsorption process. Isothermal models showed that BG adsorption was a favorable process on RC. Adsorption kinetics were well fitted by Pseudo-second order kinetic model (R-2 = 0.999). Thermodynamic study revealed that BG adsorption on RC was spontaneous, favorable and physiosorptive. The maximum adsorption capacity of RC was found to be 125 mg/g. These results showed that BG dye can be effectively removed from aqueous solution employing RC as a cheap adsorbent. (C) 2013 Elsevier B.V. All rights reserved.