Adsorption characteristics of graphene oxide as a solid adsorbent for aniline removal from aqueous solutions: Kinetics, thermodynamics and mechanism studies

The aim of this study is to investigate the possibility of graphene oxide (GO) as an alternative adsorbent for aniline removal from aqueous solution. Adsorption properties of GO for aniline removal were regularly investigated, including pH effect, adsorbent dose, temperature, contact time and initial concentration. The adsorption amount of aniline decreased with increasing pH. The experimental data were evaluated by Langmuir, Freundlich, Temkin and Harkins-Jura models in order to describe the equilibrium isotherms. Equilibrium data fitted well to the Langmuir model. The kinetic parameters achieved at different concentrations were analyzed using a pseudo first-order, pseudo second-order kinetic equation and intra-particle diffusion model. The experimental data fitted very well the pseudo second-order kinetic model. Thermodynamic parameters (free energy change, enthalpy change, and entropy change) announced that the removal of aniline from GO was endothermic and spontaneous. The study showed that GO could be used as an efficient adsorbent material for the adsorption of aniline from aqueous solution. (C) 2013 King Saud University. Production and hosting by Elsevier B.V. All rights reserved. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).