PREPARATION AND EVALUATION OF DISTILLERS' GRAINS BASED ACTIVATED CARBON FOR METHYLENE BLUE REMOVAL

In this paper, a novel activated carbon was prepared from distillers' grains by phosphoric acid activation. Orthogonal experiments were applied to optimize the activated carbon production. Sodium hydroxide was used to further improve carbon's texture structure. The characteristic of activated carbon was evaluated by SEM, FTIR and Iodine value. The adsorption capacities of the produced carbons were evaluated by uptake of methylene blue (MB) from aqueous solution. The removal of MB was investigated as a function of pH, contact time, initial MB concentration and reaction temperature. The experimental results showed that the removal of MB was pH dependent with maximum removal efficiency of 99.81% at pH 12.0. The equilibrium data were analyzed using Langmuir and Freundlich isotherm models, the maximum adsorption capacity of MB calculated from Langmuir model was 100.00 mg/g at 50 °C. The adsorption process followed pseudo-second-order kinetic, the rate constant increased with the increment of temperature, which indicated endo-thermic nature of adsorption. The negative ΔG0 values at various temperatures confirm the adsorption processes are spontaneous.