Advanced Materials Research Vols. 356-360

Abstract: A single-step sonochemical method to directly prepare rutile nanocrystal TiO₂ has been developed. TiO₂ nanaoparticles were synthesized by the hydrolysis of TiCl4 in the presence of water and ethanol under ultrasonic irradiationat 70 °C for 3 h. The crystalline forms and crystallite sizes of the produts were characterized by X-ray diffraction, transmission electron microscopy and thermogravimetry-differential thermal analysis. The TEM images showed the morphology of as-prapared TiO₂ was pinnate in shape and the average sizes were ca. 4/12 nm (W/L). The columnar particles were linked together each other at the certain principle, forming the shape like dendrite crystal. The formation mechanism of the dendrite crystal nanocrystalline TiO₂ was also discussed.

Abstract: A visible-light activated photocatalyst N-doped TiO₂ nanocrystalline was synthesized via sonochemical method at low temperature. The N-doped anatase TiO₂ nanoparticles were prapared by sonication of the solution of tetrabutyl titanium and ammonium in water and ethanol at 70 °C for 150 min. The crystalline forms and crystallite sizes of the as-prepared sample is characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-Visible absorption spectrum.The product structure was dependent upon the reaction temperature and reaction time. The photocatalytic activity of the as-prepared photocatalyst was evaluated via the photodegradation of a basic dye methyl violet. The results show that the N-doped TiO₂ nanocrystalline prepared by sonication has an excellent photocatalytic activity under UV light and simulated sunlight.

Abstract: A heterogenous Pd(II) organometal catalyst with bicontinuous cubic Ia3d mesostructure was synthesized by surfactant-directed co-condensation of Pd[PPh₂(CH₂)₂Si(OCH₂CH₃)₃]₂Cl₂ and (CH₃CH₂O)₃SiPhSi(OCH₂CH₃)₃. In water medium Sonogashira reaction, the as-prepared Pd(II)-PMO-KIT-6 exhibited higher catalytic activity than the corresponding Pd(II)-KIT-6 catalyst and could be used repetitively for more than 4 times, which could reduce the cost and even diminish the environmental pollution from heavy metallic ions, showing a good potential in industrial applications.

Abstract: Aluminum titanate has been synthesized by using industrial waste from ferroalloy plant, and titanium white as the main raw materials. The influence of MgO addition and calcining temperature on crystalline structure, micro-morphology and properties of synthesized Aluminum titanate are discussed. The synthesized product was characterized by XRD and SEM, and the crystallinity, cell parameters of crystalline phase are calculated by X' Pert plus software. The experimental result show the crystalline phase Through the research of effect of different concentration of MgO and different of calcining temperature on the crystalline structure of aluminum titanate prepared from industrial waste from ferroalloy plant, the optical concentration of MgO is 1%, and the optical calcining temperature is 1500°C.The grains of main crystalline phase aluminum titanate grow completely with typical orthorhombic feature, the average grain size of No.2 specimen in the micro structures is 10~20um.

Abstract: Studies have shown that nanometer Titanium dioxide is an excellent photocatalyst material, which owns environmental protection function of decomposing car exhaust, and it begins to be used in road works in recent years. In this paper, firstly a representative concentration ratio of each component in exhaust gas is reached according to statistical result from a large number of vehicle exhaust samples, and simulated gas used in laboratory test is prepared according to the ratio. Then substantial gas- decomposition tests are performed utilizing the self-designed sealed container and UV aging box. Applying ion chromatography to analyze the decomposition products, it is proved that nano-titanium dioxide can decompose NO_x, HC, CO and other harmful gases into nitrate and carbonate. Subsequently, an excellent concrete protection materials- anticorrosive of silane solvent is selected as dispersion solvent, and a certain amount of titanium dioxide is dispersed evenly in the solvent to make the coating material with photocatalytic performance, the brushing method and decomposition effect of the coating material are discussed. In the end, a brushing method with better decomposition effect is applied on cement collision wall on middle ring in Pudong district, while nano-titanium is also contained in the surface layer of pavement; Field measurement results show that the decomposition of car exhaust effect is obvious.

Abstract: An elevated arsenic (As) content in groundwater imposes a great threat to people worldwide. Thus, developing new and cost-effective methods to remove As from groundwater and drinking water becomes a priority. Using Zero-Valent iron (ZVI) to remove As from water is a proven technology. In this study, ZVI modified SBA-15 mesoporous silicamolecular sieves (ZVI-SBA-15), was prepared, characterized, and used for removing arsenic from water. Wet impregnation, drying, and calcination steps led to iron inclusion within the mesopores. Iron oxide was reduced to ZVI by NaBH₄, and the ZVI modified SBA-15 was obtained. Fourier-transform infrared spectroscopy confirmed the preparation process of the nitrate to oxide forms. The structure of the materials was confirmed by Powder X-ray diffraction. Its data indicated that the structure of ZVI-SBA-15 retained the host SBA-15 structure. Brunauer-Emmett-Teller analysis revealed a decrease in surface area and pore size, indicating ZVI-SBA-15 coating on the inner surfaces. Transmission electron micrographs also confirmed that modified SBA-15 retained the structure of the parent SBA-15 silica.It has a high uptake capability(more than 90 pecent) make it potentially attractive absorbent for the removal of arsenic from water.

Abstract: The mechanical properties, thermal behaviors and morphology of poly(butylene succinate) (PBS)/microcrystalline cellulose (MCC) composites were investigated. The MCC used in this study was prepared by hydrolyzing cotton fabric waste with 2.5 N hydrochloric acid at 100°C for 30 min. PBS was melt mixed with three loading of MCC (10, 20 and 30 wt%) in an internal mixer, followed by compression molding into 0.3-mm sheet. The effects of MCC on the tensile properties, thermal stability, crystallization and morphology were investigated using the Instron testing machine, thermogravimetric analyzer, differential scanning calorimeter and scanning electron microscope, respectively. The incorporation of MCC into PBS results in a significant increase in the Young’s modulus but a decrease in the tensile strength and elongation at break. Moreover, the thermal degradation of the composites was not improved after introducing MCC into PBS. It was also found that, the MCC did not affect the melting temperature, but induced a slight increase in the crystallization temperature of the composites. The SEM micrographs show brittle fracture surfaces of the composites where the pull out MCC particles and pull out holes were observed.

Abstract: ZnO is a direct wide band-gap Ⅱ-Ⅵ semiconductor material. For decades, ZnO has gained more and more attention as a wide band semiconductor. This paper introduced a modified homogeneous precipitation method to prepare sheet Ni-doped ZnO crystal. The preparation process was studied and the mechanism of this method was discussed. The properties of the sheet Ni-doped ZnO crystal and the effects of growth parameters on the quality of sheet Ni-doped ZnO crystal were studied using XTJ30-micro image manipulation system, thermal analysis system, X-ray diffraction. etc.

Abstract: The catalysts were prepared by the impregnation method and characterized thought X-ray powder diffraction (XRD), H2-temperature-programmed reduction (H₂-TPR), measurement of surface area, differial thermal and thermogravimetric analysis. Rare-earth compound oxides La _0.8Sr_0.2CoO₃ act as active component; Alumina act as carriers. The effects were investigated on loading amounts of active components, calcinations temperature and the addition components on the catalytic oxidation of xylene.

Abstract: With AlCl3 and FeSO4 as the major raw material, the preparation process of a new high polymer flocculant-polymeric aluminum ferric sulfate chloride(PAFSC) was researched, to offset the polymeric aluminum and the polymerization iron flocculants’ lacks, and draw their strong points. The product was characterized by Al-Fe-Ferron timed complex colorimetric, IR and XRD methods, to study the flocculant’s morphological characteristics. The results show that The PFASC, with better coagulating property than the market PAC, has higher contents of Alb and Al-OH-Fe bond, and the introduction of iron restrains the forming of Al-OH-Al.