Kinetic and calorimetric study of the adsorption of dyes on mesoporous activated carbon prepared from coconut coir dust

Mesoporous activated carbon has been prepared from coconut coir dust as support for adsorption of some model dye molecules from aqueous solutions. The methylene blue (MB) and remazol yellow (RY) molecules were chosen for Study of the adsorption capacity of cationic and anionic dyes onto prepared activated carbon. The adsorption kinetics was Studied with the Lagergren first- and pseudo-second-order kinetic models as well as the intraparticle diffusion model. The results for both dyes suggested a multimechanism sorption process. The adsorption mechanisms ill the systems dyes/AC follow psuedo-second-order kinetics with a significant contribution of intraparticle diffusion. The samples Simultaneously present acidic and basic sites able to act as anchoring sites for basic and acidic dyes, respectively. Calorimetric Studies reveal that dyes/AC interaction forces are correlated with the pH of the solution, which call be related to the charge distribution oil the AC surface. These AC samples also exhibited very short equilibrium times for the adsorption of both dyes, which is all economically favorable requisite for the activated carbon described in this work, in addition to the local abundance of the raw material. (c) 2006 Elsevier Inc. All rights reserved.