Highly microporous activated carbons from Mangifera indica residues: Optimization of preparation conditions using response surface methodology

Full factorial design (FFD) was applied to generate the matrix of experiments for optimizing the residence time (60–120 min), the activation temperature (600–800 °C) and the impregnation ratio (0.25 – 0.50) for the activated carbons preparation based Mangifera indica residues chemically activated. The three responses chosen namely the activated carbon yield (AcYd), the iodine number (ION) and the methylene blue number (MBN) were thoroughly studied and represented in all the experimental domain using the Minitab 16, Inc. and the Sigma16, Inc. software for regression analysis and response surface plots respectively. The results of optimization under the experimental domain revealed that the optimal conditions identified were 800 °C, 120 min and 0.50 for the activation temperature, the residence time and the impregnation ratio respectively. The aforementioned optimal conditions gave 22.7%, 1236 mg/g and 9.61 mg/g for the AcYd, ION and MBN respectively. The activated carbon prepared under this optimal condition conducted to the specific surface area of 831 m2/g as determined by the BET method, with predominance of micropores. Also, the Mangifera indica residues were found to be an effective precursor for the preparation of highly microporous activated carbons for depollution purpose.