Box-Behnken statistical design to optimize preparation of activated carbon from Limonia acidissima shell with desirability approach

Response surface methodology (RSM) coupled with Box-Behnken design (BBD) was employed to optimize the experimental conditions for the preparation of activated carbon from lignocellulosic biomass, Limonia acidissima shell by chemical activation method using phosphoric acid (H3PO4) as the activating agent. The effects of impregnation ratio, activation temperature and activation time were studied extensively. The obtained activated carbon was evaluated based on the total yield and iodine adsorption value. Each response had been described by a second-order polynomial regression model developed by ANOVA, which could properly determine the experimental data. Using desirability approach in multi-response optimization technique, following optimal conditions had been found such as impregnation ratio (24.21%), activation time (39.83 min) and activation temperature (432.35 °C). The carbon yield and iodine adsorption value approached 42.6324% and 951.889 mg/g under these experimental conditions. The predicted responses presented a good agreement with the experimental data. The results showed that activated carbons prepared by chemical activation method had a high yield as well as high iodine adsorption value. The optimized activated carbon was further characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR).