Adsorptive removal of cationic dyes from aqueous solutions using graphite oxide

Abstract

In this study, graphite oxide (GO) was prepared by a simple one-pot treatment method and used as an adsorbent for removing cationic dyes, methylene blue (MB), crystal violet (CV) and rhodamine B (RhB) from aqueous solution of different initial concentrations. We found that an increase in initial dye concentration favoured adsorption. The adsorption kinetic process fits to the pseudo-second-order equation. When compared with the expanded graphite, GO exhibits a high adsorption capability on non-acid dye molecules, with the adsorption capacities of 199.2, 195.4 and 154.8 mg•g -1 for MB, CV and RhB, respectively. An analysis of the results of UV-Vis spectra suggested that the adsorbed dye molecules represent a different form of aggregation. Meanwhile, the layered graphene structure and surface oxygen functional groups play an important role in adsorption capability.