Adsorption and Desorption Kinetics Behaviour of Methylene Blue onto Activated Carbon

In the present work investigations on a potential use of activated carbon for the removal of Methylene Blue (MB) from wastewater are presented. Adsorption kinetics of methylene blue has been studied using reaction-based and diffusion-based models. Three kinetic models, namely, pseudo-first-order, pseudo-second-order and the Elovich are analyzed at the temperature of 298 K for the reaction-based model. The kinetic studies showed that the data were well described by the pseudo-second-order kinetic model. Intraparticle diffusion, external-film diffusion, and internal-pore diffusion models characterizing MB were obtained. The results suggested that the activated carbon has a high potential to be used as an effective adsorbent for methylene blue adsorption. Pseudo first-order, pseudo second-order and the Elovich models were employed to describe the desorption mechanism. The experimental results showed that the pseudo second-order equation is the best model. About 99% of activated carbon has been regenerated by desorption. keywords: activated carbon, adsorption, desorption, kinetic studies, methylene blue