Process optimization for the preparation of activated carbon from Jatropha hull using response surface methodology

Preparation of activated carbon has been attempted using CO₂ as the activating agent from Jatropha hull, one of the popular feed stocks for biodiesel manufacture. The response surface methodology technique is utilized to optimize the process conditions. The influences of the three major parameters, activation temperature, activation time, and CO₂ flow rate on the properties of activated carbon, are investigated using analysis of variance to identify the significant parameters. The optimum conditions for preparation of activated carbon has been identified to be an activation temperature of 950°C, activation time of 40 min, and CO₂ flow rate of 500 ml/min, an iodine number of 1,008 mg/g, and a yield of 18% were obtained, respectively. The BET surface area evaluated using nitrogen adsorption isotherm for the optimal sample corresponds to a 1,207 m²/g, with the pore volume of 0.86 cc/g. The activated carbon is heteroporous with the micropore volume contributing to 58%.