Fast and Efficient Removal of Cationic Dye Using Graphite Oxide, Adsorption, and Kinetics Studies

Dye adsorption on graphite oxides, which were prepared by different methods, was compared for the first time. The adsorption process was followed using ultraviolet-visible spectroscopy, while the adsorbents before and after adsorption were characterized using physicochemical and spectroscopic techniques. Surprisingly, we found that higher oxidation degree of graphite oxide resulted in higher adsorption efficiency for methylene blue (MB), while the ultrasonic exfoliation of graphite oxide impaired the adsorption efficiency. Among all samples investigated, graphite oxide prepared by modified Hummers' method (HmGO) before ultrasonic exfoliation exhibited the best adsorption capacity of MB. It is pretty high compared with other reported absorbents for MB. The experiment conditions such as pH, adsorbent dosage, stirring speed and adsorption time on adsorption of MB on graphite oxide, as well as adsorption kinetics and isotherms, were also investigated. The maximum adsorption capacity of graphite oxide is 751.9mgg(-1) based on the Langmuir model. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Dispersion Science and Technology to view the free supplemental file.]