Treatment of pollutants in wastewater: Adsorption of methylene blue onto olive-based activated carbon

This study used olive stone-based activated carbon for the removal of methylene blue from wastewater in order to evaluate the adsorption capacity of the carbon. The equilibrium and kinetics of adsorption were examined at 25°, 30°, 35° and 40 °C and several agitation speeds. Type III adsorption isotherms corresponding to physical adsorption in a multilayer system were used for the methylene blue system. The equilibrium data for methylene blue adsorption showed a good fit to the Freundlich equation. The kinetic data was analysed to determine kinetic constants and order of reaction. Kinetics was evaluated by means of an n-order model, showing that the reaction was a first-order reaction. The results indicated that olive stone-based activated carbon could be used as a low-cost alternative to commercial activated carbon for the removal of organic compounds from wastewater. However, due to its microporosity, the application of this type of activated carbon was found to be suitable for molecules smaller than methylene blue.