ADSORPTION REMOVAL OF METHYLENE BLUE FROM AQUEOUS SOLUTION USING CORNCOB ACTIVATED CARBON: EQUILIBRIUM AND KINETICS STUDIES

The activated carbon was prepared from corncob using H3PO4 as chemical activating reagent. The H3PO4 activated corncob carbon (HACC) was characterized by nitrogen adsorption instrument, infrared spectrum (FTIR) and Boehm titration method. The optimum conditions of methylene blue (MB) sorption on HACC were found to be: 0.025g HACC in 50 mL of 25mg.L-1 with contact time of 3h and pH 7. According to adsorption isotherm studies, the Frumkin, Freundlich and D-R, isotherms were proved to be the best fit for our experimental data, in comparison to Langmuir and Temkin models. The mean free adsorption energy was 16.0 similar to 18.1 kj.mol(-1), indicating it was a feasible, spontaneous and chemical adsorption process. Four equations, namely Morris-Weber, Pseudo-first-order, Pseudo-second-order and Elovich have been used in order to determine the kinetics of removal process. The collected kinetic data showed that pseudo-second-order equations controlled the adsorption process.