Advanced Materials Research Vols. 150-151

Abstract: A new kind of PVDF/Fe3+/Cu2+ catalytic membrane was prepared and used as a heterogeneous Fenton-like catalyst to degrade Orange IV in the presence of H2O2. The effect of initial concentration of H2O2 and Orange IV, initial pH, reaction temperature and catalyst dosage on the reaction rate was studied. The results show that the higher the concentration of H2O2, the faster the reaction rate is. The reaction rate increased with the increase of temperature with the activation energy 30.18KJ•mol-1. The PVDF/Fe3+/Cu2+ catalytic membrane can effectively decolorize Orange IV in the pH range of 3.1-5.3. The decolorization rate of Orange IV decreased with the increase of initial concentration of Orange IV. The decolorization rate of Orange IV increased with the increase of dosage of catalyst. The reactive intermediates for this reaction is HO• based on t-butanol experiments.

Abstract: Sodium 2-olefinsulfonate (AOS) is used as reactive surfactant to prepare 10 nm around magnetic CoFe2O4 nanoparticles in advance. Magnetic P(St-BA-AOS)-coated CoFe2O4 composite nanoparticles has been synthesized in situ soapless emulsion. The effects of the amount of the initiator, monomer concentration and polymerizing temperature on the convention of monomer are investigated. So the polymerizing conditions are KPS=4.010-3mol/l St=0.75mol/l, mMP=20g/l, T=75 BA=0.15mol/l t=6.0h [AOS]=2% without any surfactant in the latex system. Results of IR and TEM analysis demonstrate that the desired polymer chains has been covalently bonded to the surface of CoFe2O4 nanoparticles, and confirmed that the composite particles have the core-shell structure. Copolymer P(St-BA-AOS) has a good hydrophile ability with functional groups such as -SO3Na and -COO- groups. The saturated magnetization of CoFe2O4/ P(St-BA-AOS) composite could reach 2.10emu/g, and show the characteristics of super-paramagnetism.

Abstract: A new heterogeneous PVDF/Fe3+-TiO2 catalytic membrane is prepared by sol-gel method, which had a well catalytic activity to decompose H2O2. The effect of initial pH, e initial concentration of H2O2 and Orange IV, temperature, and membrane area on the reaction rate is discussed. The PVDF/Fe3+-TiO2 catalytic membrane can effectively decolorize Orange IV in the pH range of 3.0-5.0. The optimal concentration of H2O2 is 15mmol/L. The reaction rate constant is proportional to the initial concentrations of Orange IV. The higher the temperature, the faster the reaction rate is, this reaction follows pseudo-first-order kinetics with activation energy of 1.54kJ/mol. Reuse of catalyst did not decrease the removal rate of Orange IV. The experiments of t-butanol, EDTA and XPS measurement showed that •OH, the electron hole and the ferryl are all the reactive species in the degradation of Orange IV.

Abstract: A new Fenton-like catalyst was prepared to degrade Orange IV in water by catalytic decomposition of H2O2. The optimal preparation conditions were discussed. The catalytic activity of catalyst was evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that solid super acid (S2O82-/FexOy) soaked in (NH4)2S2O8 is the most effective catalyst among the synthesized iron oxides soaked in other oxidants. The optimal conditions for solid super acid preparation are calcined at 500 for 2 h in the air.

Abstract: Co-based WC powder and self-fluxing alloy powder Ni60A were sprayed on hot work die steel H13 substrate via high velocity oxygen fuel (HVOF) spray processing, and microstructure and mechanical properties of two types of coatings were investigated. For WC-12Co coating, some pores were observed, while microcracks were only observed in Ni60A coating, which leads to the lower microhardness and abrasion-resistance at either room temperature or high temperature. At the junction of H13 substrate and WC-12Co coating, metallurgical combination was observed. Under the test condition of load 250g and rotating speed 448r/min, the average friction coefficients obtained at 10 are 0.33 and 0.35 respectively; when the test temperature was 500 , the value of two types of coatings increase to 0.56 and 0.63 respectively. Compared with Ni60A coating, The WC-12Co coating had an excellent abrasion-resistance at high temperature; the weight loss was only one-fifth of the Ni60A coating.

Abstract: Solid super acid(S2O82-/FexOy-CuOx)was prepared and used as a Fenton-like catalyst to decompose H2O2 for the removal of orgnanic pollutants in water. The catalytic activity of S2O82-/FexOy-CuOx was evaluated by the degradation of organic pollutants and the decomposition of H2O2. The results show that the catalytic activity of S2O82-/FexOy-CuOx to decompose H2O2 is higher than that of S2O82-/FexOy. The reason for this may be due to the dissolved of Fe2+ from the S2O82-/FexOy-CuOx, and the concentration of dissolved of Fe2+ is proportional to the concentration of organic pollutants in water. The degradation rate of phenol by the catalyst of S2O82-/FexOy-CuOx is obviously higher than that by the catalyst of Fe2+ ion under the same conditions. BET measurements show that the surface area of S2O82-/FexOy-CuOx is larger than that of S2O82-/FexOy.

Abstract: The photocatalytic Ag and Ni doped TiO2 films were prepared by sol-gel method and coated on glass fiber roving. The films were calcined at 500 °C for 1 hour with a heating rate of 10°C/min. The surface morphology and properties of synthesized TiO2 films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and UV-vis diffuse reflectance spectroscopy (DRS). The results show that TiO2-1Ag and TiO2-1Ag-1Ni films give rapidly kill P.aeruginosa bacteria under UV irradiation and TiO2-1Ni films give well kill P.aeruginosa bacteria under visible light.

Abstract: Bipolar plate is the key component of proton exchange membrane (PEM) fuel cell and represents a significant part of the overall cost and the total weight in a fuel cell stack. The thin sheet metal, with usually 0.1~0.3mm thickness, deformed to bipolar plate with flow channel 0.5~2mm width and depth, by rubber pad stamping can reduce the cost greatly. The rubber pad is simulated by solid element and hydraulic pressure respectively. Experiment shows that the hydraulic pressure can simulate the rubber pad. The thin sheet metal is modeled by solid element and shell element respectively. Considering thin sheet metal material size effect, the shell element cannot simulate the thin sheet metal stamping process because of small corner radius. Modeling rubber pad by hydraulic pressure and thin sheet metal by solid element, the simulation of the rubber pad stamping process shows that 1) the sheet metal in channel appears large uneven strain with high stress; 2) convex fillet make the sheet metal two direction tensions and should keep large fillet corner. Those simulations are validated by experiments. The research on rubber pad stamping will improve the understanding of this micro forming process and provide design guide of flow channel.

Abstract: Hydration mechanism and performance of tri-cementitious material, which contains clinker, limestone powder and fly ash, are studied. It is showed that when mixed materials ratio increases from 20% to 40%, the water amount for standard consistency will increase remarkably, and when dosage of limestone powder is 50% in mixed material, the water amount for standard consistency will reach minimum, i.e. 26%; but when limestone powder ratio reaches 40%, the fluidity of slurry reaches maximum, and then it drops with increasing of limestone powder ratio. It is also found that increasing of dosages of mixed materials will decrease flexural strength and compressive strength, and increasing of ratio of limestone powders can result in decreasing of compressive strength at 28 days curing time, especially when ratio of mixed material is 20%. In order to explain the rules that above-mentioned, the particles size distribution is studied, and the hydration mechanism is analyzed.

Abstract: The microstructure evolution of sputtered polycrystalline Ni54.75Mn13.25Fe7Ga25 ferromagnetic shape memory thin film annealed under different conditions is studied. Microstructure of different annealed films was studied using Transmission Electron Microscope (TEM) and corresponding selected area electron diffraction (SAED) patterns. The result shows that in the microstructure of as-deposited Ni54.75Mn13.25Fe7Ga25 free-standing film, after annealed at 1073 K for different time, the crystalline grain grows up with the increase of the annealing time. By analysis of the SAED patterns, the structure of the thin films change from face-centered cubic austenite to orthorhombic structure martensite compared between the film annealed at 1073 K for 10 mins, 1hr, 4 hrs, and 24 hrs respectively. It indicated that the heat treatment is an effective method of crystallizing behavior for the thin film.