Qingfeng Cheng

Synthesis of silver phosphate/graphene oxide composite and its enhanced visible light photocatalytic mechanism and degradation pathways of tetrabromobisphenol A

In the present study, silver phosphate/graphene oxide (Ag3PO4/GO) composite was synthesized by ultrasound-precipitation processes. Afterwards, physicochemical properties of the resulting samples were studied through scanning electron microscope, transmission electron microscope, X-ray diffraction, N2 adsorption/desorption, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, surface photovoltage spectroscopy and photoelectrochemical measurements. Results indicated that spherical Ag3PO4 displayed an average diameter of 150 nm and body-centered cubic crystal phase, which was integrated with GO. In addition, the visible light absorbance, charge separation efficiency and lifetime of Ag3PO4 were significantly improved by integration with GO. In addition, Ag3PO4/GO composite was applied to decompose tetrabromosphenol A (TBBPA) in water body. It was found that TBBPA could be completely decomposed within 60 min illumination. Furthermore, several scavenger experiments were conducted to distinguish the contribution of reactive species to the photoctalytic efficiency. Moreover, the enhanced visible light mechanism of Ag3PO4/GO was proposed and discussed. Eventually, several PC decomposition pathways of TBBPA were identified including directly debromination and oxidation, and subsequently further oxidation and hydroxylation processes.

Fabrication of Silver Decorated Graphene Oxide Composite for Photocatalytic Inactivation of Escherichia coli

In this study, silver decorated graphene oxide (Ag/GO) composite was fabricated through a reduction process in the presence of potassium borohydride solution. Subsequently, physicochemical properties of the resulting Ag/GO composite were studied by scanning electron microscope, X-ray diffraction, Raman spectra, Fourier transformation infrared spectroscopy and UV-visible diffuse reflectance spectrum. Results indicated that Ag species existed in the form of Ag0, which greatly facilitated the visible light absorbance ability. Furthermore, the performance of Ag/GO was evaluated by PC inactiviation of Escherichia coli under Xenon lamp illumination. It was found that Ag/GO sample could kill the Escherichia coli within 60 min illumination by the non-selective attack of ⋅OH radicals. This study provides a novel and facile strategy to fabricate high-efficient catalyst to kill the bacteria in drinking water treatment.

A Facile Strategy to Fabricate Nanoscale Zero-Valent Iron Decorated Graphene Oxide Composite for Dechloridation of Trichloroacetic Acid in Water

In this study, nanoscale zero-valent iron decorated graphene oxide (NZVI/GO) composite was fabricated through a reduction process in the presence of sodium borohydride (NaBH4) solution. Subsequently, physicochemical properties of the NZVI/GO composites were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR) and Raman spectra. Results indicated that Fe species existed in the form of Fe0, which uniformly dispersed on the surface of GO. Furthermore, the performance of NZVI/GO was evaluated by the degradation of tichloroacetic acid (TCAA). TCAA can be rapidly degraded by NZVI/GO. This paper provides a promising strategy to synthesize versatile catalyst which would be potentially applied in sewage treatment to degrade chlorinated organic compounds.

Synthesis of Magnetic CoFe2O4 Nanoparticles and Their Efficient Degradation of Diclofenac by Activating Persulfate via Formation of Sulfate Radicals

In this study, magnetic CoFe2O4 nanoparticles were synthesized by hydrothermal method by using ferric nitrate and cobalt nitrate as raw materials. Subsequently, physicochemical properties of the resulting CoFe2O4 nanoparticles were systematically studied by scanning electron microscope, X-ray diffraction, N2 adsorption/desorption, Fourier transformation infrared spectroscopy and Vibration sample magnetometer measurement. Results indicated that CoFe2O4 nanoparticles with cubic spinel structure possessed an average diameter of 6.9 nm, specific surface area of 103.48 m2 · g-1, saturation magnetization of 54.65 A · m2(emu · g-1) and coercivity of 1.76×104 A · m-1. Furthermore, scavenging experiments revealed that sulfate radicals (.SO-4) was the main active species derived from persulfates, in which 72.3% of diclofenac could be degraded within 30 min treatment. This study provides a promising strategy to synthesize versatile catalyst which would be potentially applied in pharmaceutical wastewater purification.