Kinetics and Equilibrium Studies of Adsorption of Direct Red-28 onto Punica Granatum Carbon

An experimental study has been conducted on the adsorption of Direct red-28 dye using activated carbon prepared from Punica granatum (Pomegranate rind) by chemical activation with sulphuric acid. BET surface area of the activated carbon was determined as 1075.6 m.g and SEM observations showed the amorphous nature of the carbon. Adsorption kinetics, equilibrium and thermodynamics were investigated as a function of initial dye concentration, temperature and pH. First order Lagergren, pseudo-second order and Elovich kinetic models were used to test the adsorption kinetics. Results were analyzed by the Langmuir, Freundlich, Tempkin and fractional power isotherm models. Based on regression coefficient, the equilibrium data was found to fit well to the Langmuir equilibrium model than other models. Response surface method using the Box-Behnken design of experiments gives a mathematical model for the adsorption of the dyestuff.