Adsorption isotherms, kinetics, thermodynamics and desorption studies of basic dye on activated carbon derived from oil palm empty fruit bunch

Abstract

The adsorption characteristics of basic dye (methylene blue, MB) on activated carbon prepared from oil palm Empty Fruit Bunch (EFB) were evaluated. The effects of dye initial concentration, agitation time, solution pH and temperature on MB adsorption were investigated. The adsorption uptake was found to increase with increase in initial concentration, agitation time and solution temperature. The adsorption equilibrium data were best represented by the Langmuir isotherm. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The mechanism of the adsorption process was determined from the intraparticle diffusion model. Boyd plot revealed that the adsorption of MB on the activated carbon was mainly governed by external mass transport where particle diffusion was the rate limiting step Thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°), standard free energy (ΔG°) and activation energy were determined. The regeneration efficiency of the spent activated carbon was acceptably high, with MB desorption of 71%. © 2010 Asian Network for Scientific Information.