Papers by Author: Pei Song Tang

Abstract: The FeS₂ was synthesized using S powder, FeCl₂4H₂O and PVP as main raw materials by solvothermal method. The FeS₂ product was characterized by XRD, SEM, DRS and TG-DTA. The results show that FeS₂ is the cube structure, particle size about 90 nm, band gap energy Eg=1.9 eV. Consequently, FeS₂ nanoparticles show high visible-light photocatalytic activity for decomposition of methylene blue, which degradation rate of 10mg/L methylene blue solution can reach to 95% for 90 min under visible-light irradiation.

Abstract: The single perovskite BiFeO₃ nanoparticles were prepared by a sol-gel process. The BiFeO₃ nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy, and Brunauer-Emmett-Teller (BET) method. It was found that the prepared BiFeO₃ nanoparticles show the large specific surface area of 136 m²/g, and narrow band gap of 2.12 eV. Consequently, BiFeO₃ nanoparticles show high visible-light photocatalytic activity for decomposition of methylene blue in comparison with the commercial Degussa P25. It is concluded that the large specific surface area and the narrow band gap contribute to the high visible-light photocatalytic activity through enhanced adsorption capability and visible-light absorption.

Abstract: To prolong blast furnace campaign life, a great deal of research work has been carried out on the structure of stave cooler in the past decades, which, in turn, produced favorable results. However, due to the different thermal expanding property of the metal stave from that of the brick lining, the latter is subjected to crack, slide and damage. To solve the problem, a new stave cooler has been developed in this paper. Thus, a certain amount of anchors were welded on the traditional stave cooler, the unshaped gunning material can be fixed by anchors and the whole-lining be formed by gunning. The results of thermal simulating indicates: the bonding strength between the surface of stave cooler with anchors and the gunning lining is much higher than that between the surface of traditional stave cooler and the brick lining. Consequently, the service life of blast furnace will be extended. The optimizing design of the anchor was also described in the paper.

Abstract: A double-sheets model was proposed to investigate the interlayer structure and properties of hydrotalcite (HT) containing CO₃^2-, CrO₄^2-, SO₄^2- and NO₃^- using density functional theory, and the configuration and distribution of four anions in the interlayer of HT were obtained. The frontier orbital of the host layer interacts with that of the guest anions, and the electron transfers from HOMO of anions to LUMO of the host layer. Moreover, the order in the absolute value of binding energy is: CO₃^2- >CrO₄^2- >SO₄^2- > NO₃^-, that remains consistent with the ion-exchange ability of HT reported.

Abstract: Using paraffin as phase change material, expanded perlite (EP) as porous materials, the EP/paraffin was prepared by vacuum impregnation treatment and tested by scanning electron microscopy (SEM). Adding other building materials, cement bricks based paraffin (CBBP) for thermal energy storage were molded and tested by means of water absorption, compressive strength and actual working of thermal energy storage. The testing results showed that paraffin was absorbed into the holes and cracks of EP, and CBBP had not linear change of various properties versus amount of cement or paraffin. Its mechanical strength was full compliance with national standard GB 21144-2007-T. At last, by phase change material exothermic or endothermic, CBBP effectively regulated outdoor surface temperature in summer: in temperature rising stage, CBBP was 4.63 °C lower than general cement bricks (GCB, no paraffin); in the cooling stage, CBBP was 2.30 °C higher than GCB.

Abstract: The two-sheets model was proposed to investigate interlayer structure and properties of Mg/Al layered double hydroxides (LDHs) containing F^-, Cl^-, Br^-, I^- and OH^- using density functional theory (DFT). The results show that four types of halogen anions in the interlayer of LDHs have the same configurations due to simple sphere structures of isolated anions. As the size of halide anions increasing, the interlayer spacing d_c increase. Mulliken charge analysis illustrates that the host layers interact with the guest anions by the electrostatic interaction and hydrogen bonding, and the charge transfers from anions to layers. The frontier orbital of the host layer interacts with that of the guest anions, and the electron transfers from HOMO of anions to LUMO of the host layer. Moreover, the order in the absolute value of binding energy is: OH^- >F^- >Cl^- >Br^- >I^-, that remains consistent with ion-exchange ability of LDHs reported.