Adsorption equilibria of methylen blue dye from aqueous solutions by using activated carbon

Abstract

In this study, activated carbon was prepared from coconut shell using sulfuric
acid activation (CSAC). Removal of methylene blue (MB) dye from aqueous solution
was performed using a batch technique for determination of the effects of initial pH,
mass dosage, initial concentration and temperature. Adsorption of methylene blue
(MB) was increased with increasing temperature, the maximum percentage removal
of 73.14% (adsorption capacity 48.76 mg.g-1), 77.07% (adsorption capacity 51.36
mg.g-1), and 81.47% (adsorption capacity 54.31 mg.g-1) for the temperature of 10 0C,
30 0C, and 55 0C respectively. Equilibrium data were mathematically modeled using
the Langmuir, Freundlich, Fritz-Schelunder adsorption models to describe the
equilibrium isotherms at different dye concentrations and temperatures, parameters of
best-fit model were calculated and discussed. It was found that pH plays a major role
in the adsorption process; adsorption capacity was influenced by the physical and
surface chemical properties of carbon and the pH of the solution. Change in Gibbs
free energy (ΔG), entropy (ΔS), and enthalpy (ΔH) were also calculated, from the
adsorption results were found the adsorption process was endothermic.