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In this work, we report a room-temperature approach to synthesizing reduced graphene oxide/NiO (RGO/NiO) nanocomposites. The chemical structure of RGO/NiO nanocomposites were investigated by Transmission Electron Microscope (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray power diffraction (XRD). It is shown by the experiment that the RGO/NiO nanocomposites have strong capacity to absorb the hexavalent chromium ion (Cr (VI)), the maximum adsorption capacity of Cr (VI) on RGO/NiO nanocomposites at pH = 4 and T = 25 °C can reach 198 mg g −1 , higher than any other currently reported. The adsorption kinetic data were well described by a pseudo-second-order model. Both Freundlich and Langmuir isotherm models were applied to the experimental data analysis, and the latter proved to be a better fit. The pH value markedly affected the adsorption behavior of RGO/NiO nanocomposites, but the effect of temperature was insignificant. The probable mechanism of synergistic adsorption of Cr (VI) ions was considered. These results suggest that RGO/NiO nanocomposites have the potential to be applied in industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

In the present study, a poly(Rhodamine B)/graphene oxide/multiwalled carbon nanotubes nanocomposite modified glass carbon electrode (PRhB/GO/MWCNTs/GCE) was developed for the simultaneous determination of 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP). The PRhB/GO/MWCNTs film was extensively characterized by emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of 2,4,6-TCP and PCP were investigated by cyclic voltammetry, linear sweep voltammetry and differential pulse voltammetry. Due to the synergistic effect, the PRhB/GO/MWCNTs/GCE significantly facilitated the simultaneous electro-oxidation of 2,4,6-TCP and PCP with peak potential difference of 160 mV and enhanced oxidation currents. Under optimum conditions, the oxidation current of 2,4,6-TCP was linear to its concentration in the ranges of 4.0 × 10 −9 to 1.0 × 10 −7 M and 1.0 × 10 −7 to 1.0 × 10 −4 M with the detection limit (S/N = 3) of 8.0 × 10 −10 M. And the linear concentration ranges for PCP were 2.0 × 10 −9 to 1.0 × 10 −7 M and 1.0 × 10 −7 to 9.0 × 10 −5 M with the detection limit of 5.0 × 10 −10 M. Moreover, the proposed PRhB/GO/MWCNTs/GCE was successfully applied to the simultaneous determination of 2,4,6-TCP and PCP in practical water samples. [ABSTRACT FROM AUTHOR]

A facile approach of fabricating homogeneous graphene oxide (GO)-wrapped Bi 2 WO 6 microspheres (GO/Bi 2 WO 6 ) is developed. The transmission electron microscopy (TEM) results show that a heterojunction interface between GO and Bi 2 WO 6 . The UV–vis diffuse reflection spectra (DRS) reveal that the as-prepared GO/Bi 2 WO 6 composites own more intensive absorption in the visible light range compared with pure Bi 2 WO 6 . These characteristic structural and optical properties endow GO/Bi 2 WO 6 composites with enhanced photocatalytic activity. The enhanced photocatalytic activity of the GO/Bi 2 WO 6 is attributed predominantly to the synergetic effect between GO and Bi 2 WO 6 , causing rapid generation and separation of photo-generated charge carriers. [ABSTRACT FROM AUTHOR]