Papers by Author: He Yang

Abstract: Highly ordered TiO₂ nanotube array hasbeen widely used as the dye-sensitized solar cells’ (DSSCs) light anode material forits abilities of inhibiting electronic recombination at the interface and improving the beam transmission of the carrier. The morphology and structure of the nanotube would influence the efficiency of the cell. In thisstudy, TiO₂ nanotubes (caliber ranging from 50 to 150nm, length ranging from 0.9 to 4μm) were prepared by a two-step anodization method and the morphology of nanotubes was regulated bythe parameters such as oxidation voltage and oxidation time. The absorbing capacities of nanotubes were measured by the dye adsorption test and the corresponding photoelectric conversion efficienciesweremeasured too. The results indicated that the conversion efficiency was related to the specific surface area and length of the nanotube. The length of nanotube would increase with theoxidation time within acertain limit.Then thedissolution on the top of TNT would reduce nanotubes’ length and lead to the decrease of the specific area, eventuallyimpairedthe photoelectric conversion.

Abstract: The paper preliminary studied the photocatalytic efficiency of the filter residue of the acidolysis of high titanium slag (RAHTS) with hydrochloric acid, and explored the photocatalytic efficiency on the acid methyl orange solution under the mercury lamp irradiation. With RAHTS performing as a raw material to react with hydrochloric acid, and then the substance content, nature and catalytic efficiency of the filter residues were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and photocatalytic reaction apparatus. Through the experimental investigation, the photocatalytic degradation efficiency on the methyl orange of the filter residues increased with the acid-sludge ratio, reaction time, reaction temperature, and the concentration of hydrochloric acid. When the temperature was 100°C, the reaction time was 4 h, the concentration of the hydrochloric acid was 6 mol/L, the acid-sludge ratio was 1, the filter residues showed a best photocatalytic degradation efficiency. Under that experimental condition, the degradation rate was as high as 85.1%.

Abstract: In this paper, steel slag as the main raw material, modified steel slag adsorbent was prepared using steel slag and the active carbon as the starting materials. The influences of doping substance, the particle size, calcining temperature and doping ratio on the decoloration rate of methyl orange wastewater were investigated. The results showed that the decoloration rate of methyl orange can reach 93.62% when the doping substance was the activated carbon, the particle size was 120 mesh, the calcining temperature was 700°C, the doping ratio was 1:1.

Abstract: Iron titanate photocatalysts were synthesized by the high-energy ball milling method with titanium ore as the starting material. X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), thermal gravity and differential thermal analysis (TG-DTA), UV-visible diffuse reflectance absorption spectra (UV-Vis), photoluminescence emission spectra (PL) and photocatalytic degradation measurement were conducted to characterize the structure, surface status, UV-visible light response and performance of the obtained sample. After low temperature calcination (above 400 oC), the photocatalytic activity of iron titanate catalyst decreased gradually, which was mainly due to the decrease of surface hydroxyls and reactant adsorption capability.

Abstract: The paper investigates the feasibility to reduce Cr (VI) from the aqueous solution by sulfate-modified titanium-bearing blast furnace slag (STBBFS) prepared with the different preparation method. The different photocatalysts were examined by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra and scanning electronic microscopy (SEM). The photocatalytic activities of the different catalysts were evaluated by the photocatalytic reduction of Cr (VI) under UV-vis light irradiation. For the photocatalytic reduction of Cr (VI), the photocatalytic activities of STBBFS catalysts were found to be strongly dependent of absorbance in UV-visible region, adsorption capacity and surface acidity, and STBBFS prepared by dry-process showed a higher photocatalytic activity compared to that prepared by hydro-chemistry method.

Abstract: The four main effect production factors, doping rate, calcination temperature, soaking time and heating rate, are chose to design experiments based on the orthogonal table L₉(₃⁴) to prepare urea-modified titanium ore (UTO) sorbents. And the decoloration efficiency of methyl orange is examined by using UTO as sorbents under dark-state absorption. Based on the orthogonal experiments, we obtained the optimal operating parameters: urea 8.0wt%, soaking time 3h, calcination temperature 300°C and heating rate 10°C/min. As the preparation condition was run at the optimal conditions, the decoloration efficiency of methyl orange reached 98.1%, which was significantly better than the undoped samples. Thus, it is feasible to treat dye wastewater by these UTO sorbents.

Abstract: Using calcined sulfate-modified titanium-bearing blast furnace slag (STBBFS) as photocatalyst, decolorization efficiency of methyl orange (MO) in the presence of Cr(VI) were studied. The effect of solution pH on the decolorization efficiency of MO and reduction efficiency of Cr(VI) have been investigated. The results indicate that the acidic solutions are favorable for the photocatalytic oxidation of MO in the presence of Cr(VI), and the optimum pH for oxidation of MO is 1.5. The increasing of photocatalytic activities in the compound system can be attributed to five main reasons: (1) the redox reaction between Cr(VI) and MO; (2) adsorption of Cr(VI) species and dye molecule onto STBBFS surface; (3) the visible light irradiation; (4) Cr(VI) species reduced to Cr(III) by Mn2+ in STBBFS photocatalyst; (5) Moreover, the addition of Cr(VI) species able to act as electron scavengers to catalyst surface promotes the effective separation of electron-hole, and hence promote the increase of decolorization efficiency of MO and reduction efficiency of Cr(VI) in Cr(VI)-MO system under visible irradiation. UV-vis spectral analysis indicated that MO was completely mineralized in the presence of Cr(VI) after 240 min. FTIR spectral analysis showed that all these characteristic peaks of Cr(VI) and MO disappear after photoreaction, indicating the degradation of Cr(VI) and MO.

Abstract: High temperature electrochemical synthesis of tungsten boride has been performed in KF-KCl melts with B₂O₃ and WO₃ used as reactants at 1033K. The cathode product was investigated in the current density range 0.4A/cm²-0.6A/cm² and characterized by means of XRD analyses and SEM. The results indicated that cathode product is mainly consist of W₂B₅ and WB₄, the powders are fine (＜0.5um). Current density exert a great effect on the phase composition, particle size and morphology of the cathode product.

Abstract: Three kinds of low cost shielding materials using boron-containing ores and epoxy as starting materials were developed. The three boron-containing ores consist of natural green ore that is specific in China and the two artificial minerals that are boron-containing iron ore concentrate and boron-rich slag. They were got after natural green ore dressing and separation from blast furnace, respectively. The shielding performance of slow neutron and ⁶⁰Co γ ray among the three shielding materials were compared. The results show that boron-rich slag as neutron absorber performs relative good slow neutron shielding ability, its macroscopic cross section (Σ) is 0.271cm^-1 which is about 1.72 times higher than Lead-Boron Polyethylene B201 whose macroscopic cross section (Σ) is 0.158cm^-1. Boron-containing iron ore concentrate/epoxy composite performs relative good ⁶⁰Co γ ray shielding ability and its linear attenuation coefficient (μ) is 0.0772cm^-1. The elements boron and iron that exist as compound in ore are the main reasons to affect the slow neutron shielding performance. The iron element that exists as compound in the ore has the main attribution to ⁶⁰Co γ ray shielding.

Abstract: Photocatalyst of perovskite type V-doped titanium-bearing blast furnace slag (VTBBFS) were prepared by high temperature solid-state method with different concentration of V for 2 hours at 800°C. The structure and composition of VTBBFS photocatalyst was characterized by XRD, UV-vis absorption spectra, and SEM images. It shows that VTBBFS photocatalyst has perovskite structure, and a kind of irregular and massive particles by calcined at 800°C. Its photo absorption performance was checked by UV-Vis spectrophotometer, its absorption spectrum has a obvious red shift. Use Aspergillus Niger to research the antibacterial activities of VTBBFS photocatalyst. The results show the antibacterial activities of VTBBFS photocatalyst has a good antibacterial performance with 5% diluent of VTBBFS15 under the UV light.