Papers by Author: Wen Li Zhang

Abstract: Different molecular weights of polyacrylic acids were prepared through change the molar ratio of acrylic acid (monomer), sodium bisulfate (chain transfer agent) and potassium sulfate (initiator). Using polyacrylic acid as the intercalation agent, the intercalation method was applied to Suzhoutu modification. The paper researched the affections of intercalation agent’s molecular weight on fluidity, thixotropy, absorption rate and plasticity of pulp. The changes in the interplanar spacing of clay were detected by X-ray diffraction analysis. Results showed that appropriate molecular weight of the polymer intercalation agent has little effect on the interlayer structure of Kaolinite, while the effect is obvious to Illite, and processability of the clay was significantly improved.

Abstract: The ZnFe₂O₄ and TiO₂ nanocomposite films was prepared by Sol-Gel method on conductive glass, and the influence factors of it’s photoelectrocatalytic performence such as the film layer, pole and voltage was investigated. The results indicated that: the photocatalytic effects of composite films with ZnFe₂O₄+ TiO₂+ ZnFe₂O₄ was the best. The decomposing ratio of methyl orange with the photoelectrocatalysis of composite films at voltage 0.2-6V all increased unstably.At the same time, the distance from films to pole plank also had the effects on the photocatalytic activities of the films.

Abstract: This paper studied the preparation of TiO₂ whisker with melt phase-splitting method, which used tataniferous blast-furnance as the main raw materrial. XRD and SEM were used to research the phase and morphology of the sample, and by the same time, the photocatalytic properties of TiO₂ crystal-beards was tested.The result have shown:the size of TiO₂ crystal-beards was sub-micron rank, the crystal type wasβ-TiO₂ of orthorhombic high-pressure phase. The generation of TiO₂ crystal-beards were effected mainly by the content of Na₂O and TiO₂, and the heat treatment temperature. The sample had certain photocatalytic properties and the highest photocatalytic efficiency was 56%.

Abstract: The titaniferous blast furnace slag was selected as a kind of main raw material in the glass preparation. The glass system was separated phase into boron-rich phase and silicon-rich phase in Na2O-CaO-Al2O3-B2O3-SiO2-TiO2 system, and the changes of the two-phase composition after heat treated at different temperatures were studied. Results indicated that the network adjustment oxide existing in boron-rich phase was only CaO when phase separation temperature was below 750°C, and Na2O concentrated in silicon-rich phase. With the phase separation temperature rising, the distribution of Al2O3 and CaO was almost unchanged, whereas Na2O transferred from the silicon-rich phase to boron-rich phase gradually. In the phase separation process, TiO2 concentrated and crystallized on the phase separation interface.

Abstract: A new strategy involving the introduction of the common cationic surfactant cetyltrimethyl ammonium bromide (CTAB) for the cathodic electrodeposition of ZnO electrodes from Zn(NO3) solutions by cyclic voltammetry has been developed. Frizzily lamellar and porous ZnO films were obtained. The deposited films were characterized by X-ray diffraction (XRD) in the range of low-angle and wide-angle, X-ray photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM), and UV-Vis transmittance spectroscopy. The role of the CTAB was also discussed. Under the optimal contents of CTAB, the XRD pattern shows that the as-synthesized ZnO is lamellar nanostructure and SEM image demonstrates that porous and frizzyly lamellar ZnO crystals are formed; XPS spectra of as-deposited film shows that the electrodeposition mainly consists of Zn and O and the Optical transmittance spectra of ZnO film indicates that optical transmittance is low and gradually decreases with the wavelength lessening in the visible light region. Mechanisms are proposed for the electrochemical deposition and the beneficial role of CTAB.

Abstract: The basic compositions of the samples were selected inside and outside of Na2O-B2O3-SiO2 glass phase separation region, respectively. Nanocrystalline TiO2 was crystallized by melt-phase separation process. The results showed that the phase separation of Na2O-B2O3-SiO2-TiO2 glass system was advantaged to TiO2 nucleation and growth, and then the formation of the nanocrystalline. The main mechanism of TiO2 crystallization is that the rich alkali-boron phase has the lower viscidity and higher particles moving ability than that of parent phase glass. Therefore, the movement rate of TiO2 particle can be promoted and TiO2 crystallization can be accelerated. Moreover, the formation of non-homogeneous nucleus situation and the centralization function of TiO2 have less contribution to TiO2 crystallization.

Abstract: The principle of melt-phase separation process for preparation of nanoparticle TiO2 is based on the adjustment of glass phase-separation structure. TiO2 grain size can be controlled by changing heat treatment temperature. The sample was composed of Na2O-B2O3-SiO2-TiO2 glass system (melted at 1573K). A photocatalytic nanoparticle TiO2 which was loaded on porous glass can be obtained by heat treatment of glass system at various temperatures and then acid washing. The results have shown that the glass phase-separation structure size matches crystallization rate and an optimal photodegradation property of TiO2 is achieved. It was found that the suitable heat treatment condition was at 848K for 12h, although its performance slightly changes with the composition variations.

Abstract: The uniform and transparent nano-crystalline thin films of pure and co-doped with Fe3+/Sn4+ titanium dioxide photo-catalysts were prepared via sol-gel dip-coating process, and were loaded firmly on the surface of glass substrates. The structure and surface morphology of films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). In particular, the photo-catalytic activity of films was measured by ultraviolet-visible (UV-VIS) spectrophotometer. Methyl orange was used as a model compound to study the photo-catalytic activity of films. The effects of the concentrations of doping ions and the number of layers on photo-catalytic degradation of methyl orange solutions were investigated. Experimental results showed clearly that the co-doping of iron and tin ions exhibited a synergistic effect, which increased significantly the photo-catalytic activity of titanium dioxide. Especially, the photo-catalytic activity of nano-crystalline titanium dioxide thin films co-doped with 0.1 mol%Fe3+ and 11.41mol%Sn4+ was 2.0 times higher than that of those un-doped for photo-degradation of methyl orange solutions under the 125W self-ballasted fluorescent high-pressure mercury lamp irradiation.