Papers by Author: Min Wang

Abstract: Pd/FeVO₄ composite photocatalysts were synthesized by the impregnation method.The as-prepared samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM).And the obtained samples were characterized by XRD, SEM and BET. The effect of Pd-loaded contents on their photocatalytic activity was studied by photocatalytic oxidation of methyl orange under 20 W UV light irradiation. The mechanism was also analysised. The results show that PdO can remarkably affect the photocatalytic activity.The photocatalyty activity of Pd-loaded FeVO₄ was significantly enhanced and the decolorization rate of MO can be increased 27% more than that of pure FeVO₄ sample when loading content is 3.5wt %.

Abstract: The N-doped Cu11O2 (VO4)6 photocatalyst was prepared using the sol-gel method. Techniques of X-ray diffraction (XRD), scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of Methy lorange(MO) under the UV-light, the as-prepared N-doped Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6 without doped N. It found that the N-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, N/Cu molar ratio of 12%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 94.42% or so in 60min under 20W ultraviolet lamp.

Abstract: Nd-doped Cu11O2 (VO4)6 photocatalyst was synthesized by complexing Sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy Dispersive X-Ray Spectroscopy(EDX). The photocatalytic activity of Nd-doped Cu11O2 (VO4)6 was evaluated by photocatalytic degradation of methyl orange (MO) solution under UV-light. It revealed that the Nd-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, Nd/Cu molar ratio of 2%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 95.73% or so in 60min under 20W ultraviolet lamp.

Abstract: The biosorption of C. I. Reactive Red, from aqueous solutions by calcium alginate immobilized Penicilium sp. biomass was studied in a batch system. The effects of solution initial pH, temperature, NaCl concentration and initial dye concentration on dye biosorption were investigated. In batch experiments, the dye removal efficiency decreased with increase in solution pH, and the maximum dye biosorption of immobilized biomass was 93.20% at pH 2. In the contrary, the percentage of dye removal was increased in the dye biosorption with the increasing temperature in studied temperature. The Langmuir and Freundlich isotherm models were applied to experimental equilibrium data and the Langmuir model better described the equilibrium dye uptake than the Freundlich model. According to the Langmuir model, the maximum dye uptake was obtained as 120.48mg/g. The results indicate that the immobilized Penicilium sp. biomass can be used as an effective biosorbent to removal C. I. Reactive Red from aqueous solution.

Abstract: Silver (Ag⁺) doped iron (III) vanadate (FeVO₄) samples are prepared by the precipitation method and then characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy(XPS). The photocatalytic activity under visible light is evaluated by photocatalytic degradation of methyl orange (MO) in the solution. The results show that both FeVO₄ and Ag⁺ doped FeVO₄ samples are triclinic, the later have different surface morphology, and some needle-shaped materials appear in the later. From XPS, there are more Fe²⁺ ions in Ag⁺ doped FeVO₄ sample than that in FeVO₄ one without Ag⁺. It indicates that Ag⁺ doping can increase the density of the surface oxygen vacancies of catalysts, which can act as electron traps promoting the electron-hole separation and then increase the photo-activity. The decoloration rate after Ag⁺ doping against methyl orange solution can reach about 81%, and be more about 20％ than that of pure FeVO₄.

Abstract: BiVO4/FeVO4 composite photocatalyst samples were prepared by calcining the mixture of FeVO4 and BiVO4 precusor which were prepared through liquid phase precipitation method for further increasing the photocatalytic efficiency of FeVO4. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microsoope（SEM）and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns indicate that BiVO4/FeVO4 composite photocatalysts consist of triclinic phase and the lattice was not distorted beacause of doping Bi. But the morphology change greatly and the specific surface area has little change. In the experimental conditions used, the optimal photocatalytic activity for all the prepared samples was reached when BiVO4 doping was 22 at%. The degradation rate of MO was increased by 20％ or so than that of pure FeVO4.