Accelerating effect of bio-reduced graphene oxide on decolorization of Acid Red 18 by Shewanella algae

In this study, the effects of bio-reduced graphene oxide (BRGO) on the bio-reduction of Acid Red 18 (AR 18) by Shewanella algae were first investigated, and a possible mechanism of BRGO-mediated AR 18 bio-decolorization was proposed. The prepared BRGO was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), infrared spectroscopy (IR), Raman spectra, and transmission electron microscope (TEM), respectively. Moreover, electrochemical experiment demonstrated that BRGO is of good electrical conductivity. AR 18 bio-decolorization could be enhanced in dose-dependent manner of BRGO. The maximum increase in AR 18 removal efficiency was observed at a dose of 0.075 g L(-1) BRGO. Under the same conditions, BRGO could also improve the decolorization rates of Acid Red 88, Acid Red 27, and Acid Red 73. During decolorization, the formation of BRGO and cells composite was observed, which is beneficial for transferring electrons from cells to BRGO. In addition, BRGO could accelerate the bio-decolorization of AR 18 under saline conditions (2-7 %). These findings indicate that BRGO can accelerate the electrons transfer from cells to azo dyes.