Optimization of preparation conditions of activated carbon from nut oil cake using response surface methodology

Abstract

The response surface methodology has been used to optimize the preparation conditions of activated carbon from nut oil cake by phosphoric acid activation. The Doehlert design and Desirability function were applied to determine the optimal conditions. The yield in carbon, the adsorption of methylene blue and iodine have been studied and represented in all experimental regions of activation temperature and impregnation ratio, which are the most influential factors in the preparation of activated carbon. The increase in activation temperature and impregnation ratio increases the adsorption capacity of methylene blue and iodine. The optimal conditions for the preparation of activated carbon have been identified to be an activation temperature of 465 °C and impregnation ratio of 1.63. The characteristics of activated carbon obtained under these experimental conditions were determined using adsorption capacity of methylene blue and iodine, X-ray powder diffraction, SEM/EDX, surface functions based on FTIR and pH_pzc. The maximum adsorption capacity of methylene blue and iodine was found to be 270.38 mg.g^-1 and 582.35 mg.g^-1 respectively. The produced activated carbon had a well developed porous structure and a pH_pzc of 4.6. The FTIR analysis indicates presence of variety of functional groups on the surface of activated carbon. These results demonstrated that the nut oil cake is a suitable precursor for the production of activated carbon.