Revisit the adsorption of aromatic compounds on graphene oxide: Roles of oxidized debris

Abstract

The latest structural model of graphene oxide (GO) consists of two parts: large sheet of lightly oxidized graphene (FG) and small highly oxidized debris (ODs) in the form of “GO = FG + ODs”. Given the new model, this study focused on the roles of ODs played in the adsorption of aromatic compounds on GO. Firstly, π-conjugation, hydrophobicity, and surfaces charges of GO were examined to reveal how ODs stripping affected the surface property. Then, microscopic adsorption process was captured to reveal the behaviour of ODs during the adsorption process. Finally, isothermal and kinetics experiments were carried out to explore the effects of ODs striping on adsorption capacity and adsorption rate of GO. The results showed that ODs play key roles during the adsorption process and serves as important adsorption sites towards aromatic compounds. The adsorption was enhanced upon the significant stripping of ODs and was mainly attributed to the weakened electrostatic repulsion, increased π-π interaction, and increased hydrophobic interaction between GO and the aromatic compounds. Therefore, ODs should be considered during the development of GO-based environmental nanomaterials for applications.