Facilitated biological reduction of nitroaromatic compounds by reduced graphene oxide and the role of its surface characteristics

Chuan-Shu He,Lei Li,Yi-Xuan Wang,Hou-Yun Yang,Yang Mu,Han-Qing Zhao,Han-Qing Yu,Li Gong,Qi Liu

doi:10.1038/srep30082

Abstract

How reduced graphene oxide (RGO) mediates the reductive transformation of nitroaromatic pollutants by mixed cultures and the role of its surface characteristics were evaluated in this study. Different electron donors were applied to investigate the interaction between RGO and anaerobic microbes. Moreover, the influence of the surface properties of RGO on biological nitroaromatic removal was further elucidated. The results show that RGO could achieve an approximate one-fold rate increase of nitrobenzene reduction by mixed culture with glucose as an electron donor. Selective elimination of oxygen moieties on the RGO surface, such as quinone groups, decreased the nitrobenzene transformation rate, whereas doping nitrogen into the RGO framework exhibited a positive effect. The study indicates that graphene-based carbon nanomaterials have the potential to accelerate the biological transformation of nitroaromatic compounds and that the functionalization of these carbon nanomaterials, especially through surface modification, would further enhance the conversion efficiency of contaminants.

Highlights

Shuttle for the increased redox conversion of contaminants in biological systems[20]
The shift of (002) peak could be explained by the remaining oxygen moieties on the reduced graphene oxide (RGO) structure
The nitrogen-doped graphene (NG) sample exhibited a closer interlayer spacing to graphite by shifting the X-ray diffraction (XRD) peak to 26.4°

Summary

Introduction

Shuttle for the increased redox conversion of contaminants in biological systems[20]. Surface modification of carbon materials would affect their performance. There was lack of sufficient information about the role of graphene as well as its surface characteristics especially through the modification by nitrogen doping on the biological reduction of nitroaromatic compounds with mixed cultures. The specific objectives of this study include: (1) to elucidate how RGO affects electron transfer in the reduction of NACs by mixed anaerobic microorganisms; and (2) to clarify the effect of RGO surface characteristics, including oxygen moieties and nitrogen doping, on biological nitroaromatic conversion. Nitrobenzene was selected as the model NAC in this study because it is widely used and listed as a priority pollutant in many countries[24,25]

Objectives

Methods

Results