Preparation of oil palm empty fruit bunch based activated carbon for adsorption of dye from aqueous solution

Department of Chemical Engineering, Mahanakorn University of Technology, Bangkok 10530, Thailand

Corresponding author: narisara@mutacth.com

Abstract

The objectives of this research are to determine an optimum condition for producing the activated carbon from oil palm empty fruit bunch (OPEFB) and used as an adsorbent to remove methylene blue (MB) dye from aqueous solution. Chemical activation by phosphoric acid (H₃PO₄) was used as a procedure to modify OPEFB, in which in this study the carbonization and activation were done simultaneously. The concentrations of phosphoric acid were varied from 20-60% by weight and carbonization temperature and time were varied from 500-800^oC and 30-60 minutes, respectively. It was found that among the conditions used, the best condition for producing activated carbon was obtained when using 60% H₃PO₄ and carbonized at 500^oC for 30 minute. The produced activated carbon had a surface area of 362.5 m²/g and average pore size of 2.94 nm. Methylene blue and Iodine numbers were 13.62 and 356.46 mg/g, respectively, which were comparable to the results of commercial activated carbon; i.e. 6.96 and 778.7 mg/g. The optimum condition for the adsorption of MB from synthetic wastewater by produced activated carbon was found at pH 8-12 with equilibrium time of 4 hours. Results demonstrated that the equilibrium data was well fitted by Freundlich isotherm model with the isotherm constants K_F of 7.75 mg/g and 1/n of 0.13.