Graphene oxide (GO) contains not only aromatic carbon lattice but also carboxyl groups which enhanced the aqueous solubility of GO. However, as a typical nanomaterial, GO sheets can be easily dispersed in water and may affect the aqueous environment. To study the transformation of GO nanosheets in natural environments, GO aqueous dispersion was mixed with Fe3+ ions to form photoactive complex. Under visible light irradiation, Fe(III) of the complex would be reduced to Fe(II) which could subsequently reduce highly toxic Cr(VI) to Cr3+. The electron of the reduction was contributed by the decarboxylation of carboxyl groups on GO and iron was acting as a catalyst during the photoreduction. On the other hand, the consumption of carboxyl groups may convert GO to rGO which are tend to aggregate since the decreased electrostatic repulsion and the increased π-π attraction. The formed Cr3+ may be electrostatically adsorbed by the rGO sheets and simultaneously precipitated with the aggregated rGO sheets, resulting the effective removal of chromium and GO nanosheets from the aqueous environment. The transformation of GO in a aqueous environment containing Fe3+ and Cr(VI) under sunlight is of crucial environmental importance but lack of study. Thus, this study may shed a light on understanding the environmental transformation of GO and guide the treatment of Cr(VI).

Photoreduction, adsorption and aggregation of graphene oxide-Fe(III) complexes for the efficient removal of Cr(VI) under visible-light irradiation

254th National Meeting (2017)

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