Coconut husk derived activated carbon via microwave induced activation: Effects of activation agents, preparation parameters and adsorption performance

Preparation of activated carbon has been attempted from coconut husk (CHAC) via microwave assisted chemical activation. The operational parameters including the effects of activation agents, chemical impregnation ratio (0.25-2.00), microwave power (90-800W) and irradiation time (4-8 min) on the carbon yield and adsorption capability were investigated. CHAC was examined by pore structural analysis, Scanning Electron Microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption isotherm, elemental analysis, and zeta potential measurement, while the adsorptive property was quantified using methylene blue (MB) as dye model compound. The best conditions (KOH as activating agent, IR of 1.25, microwave power of 600 W and radiation time of 6 min) resulted in CHAC with a monolayer adsorption capacity of 418.15 mg/g for MB and carbon yield of 80.75%. The BET surface area, Langmuir surface area and total pore volume were identified to be 1356.25 m(2)/g, 2040.01 m(2)/g and 0.780 m(3)/g, respectively. Equilibrium data were favorably described by the Langmuir isotherm, while the adsorption kinetic was satisfactory fitted to the pseudo-second-order model. (C) 2012 Elsevier B.V. All rights reserved.