Equilibrium, kinetics and mechanism of malachite green adsorption on activated carbon prepared from bamboo by K2CO3 activation and subsequent gasification with CO2

In this work, the adsorption of malachite green (MG) was studied on activated carbon prepared from bamboo by chemical activation with K2CO3 and physical activation with CO2 (BAC). Adsorption studies were conducted in the range of 25-300 mg/L initial MG concentration and at temperature of 30 degrees C. The experimental data were analyzed by the Freundlich isotherm, the Langmuir isotherm, and the multilayer adsorption isotherm. Equilibrium data fitted well with the Langmuir model with maximum adsorption capacity of 263.58 mg/g. The rates of adsorption were found to confirm to pseudo-second-order kinetics with good correlation and the overall rate of dye uptake was found to be controlled by pore diffusion throughout the entire adsorption period. The results indicate that the BAC could be used to effectively adsorb MG from aqueous solutions. (c) 2008 Elsevier B.V. All rights reserved.