Advanced Materials Research Vols. 287-290

Abstract: With the development of the science and technology, environmental pollution becomes one of the most serious problems all over the world. TiO₂ has gained intense research in the past decades due to its applications in environmental purification and solar energy conversion. In this paper, we discuss the influence of nonmetal (N, P, S) doped TiO₂ were prepared by hydrothermal method, the samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of them was evaluated for the degradation of methylene blue under xenon lamp which has similar spectra to solar light. The results domenstrated that the N, P-codoped TiO₂ powders exhibited a better photocatalytic activity, and the optimum molar ratio is also investigated.

Abstract: P-doped titania was synthesized by a one step hydrothermal method and sol-gel method, which is characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The samples prepared by hydrothermal method demonstrate higher photocatalytic activity toward the degradation of methylene blue under xenon lamp which has similar spectra to solar light, and also is much superior to that of the commercial P25. The as prepared P-doped titania shows a small particle size (the minimum reaches to 4.5 nm). In addition, the samples prepared by hydrothermal treatment could severely influence the crystal lattice structure. Morever, P-doped titania can further enhacnce the photocatalytic activity effectively, and hydrothermal treatment is a very suitable method for the synthesis of P-doped titania. This excellent performance could endow the as-prepared P-doped titania potential in purifying wastewater.

Abstract: This paper studies the photodegradation of dichlorvos pesticide residues in vegetables by ultraviolet excimer and direct sunlight. It was observed that the degradation of pesticide residues in vegetables conforms to the dynamic equation for pesticide degradation. The decomposition rate of the same concentration of organophosphorus pesticide was found to vary in different vegetables. This is attributed mainly to the pigments because chlorophyll pigments in different vegetables can stimulate the dichlorvos photodegradation. Through the uv excimer, the residual pesticide in the vegetable can be effectively removed in a short period of time, while the appears to be no adverse affects from this process. Therefore, it is possible to achieve a selective degradation of residual pesticides in vegetables through the use of uv excimers.

Abstract: The present paper studies the removal of the nitrogen in the form of nitrate in water by electrochemical catalysis reduction. The influence of electrode materials and various test conditions on the removal efficiency was studied. The experimental results show that the removal rate of nitrate can reach above 90% by using a three-dimensional permeable electrode of Fe-Si alloy under the condition of flowrate of 600ml/h, current density of 10mA/cm² and reaction time of 2h.

Abstract: A new type of low-heat accumulation asphalt concrete material has been made to reduce urban surface temperature and to ease the urban heat island effect. The test has investigated the temperature reduction performance and pavement performance, established a non-gray model of the atmospheric temperature field, and evaluated its effect on the urban thermal environment. The results show that compare specimens mixed with infrared powder with normal ones, the higher the infrared powder content, the lower the surface temperature, but the cooling rate decreases; the properties of high-temperature stability, low-temperature stability and water stability are improved; under the same temperature and humidity conditions, the surface layer temperature of the former pavement is lower generally; under the same radiation conditions, the surface equilibrium temperature of the former ones is 8.12K lower, which can reduce the near-earth atmospheric temperature and ease the urban heat island effect.

Abstract: Poly(butylene succinate)(PBS) is a kind of biodegradable materials. In this paper PBS foaming materials is prepared by physical foaming method of one-step compression molding. The influences of blowing agent and nucleating agent, the foaming temperature and foaming time on the cellular morphology of PBS foaming materials have been studied. The results showed that when the foaming temperature was 160°C，the blowing agent content was 5 parts, the foaming pressure was higher than 10 MPa, and the foaming time was 20 minutes with nucleating agent addition, the cellular morphology and mechanical properties of the foaming materials were better. The results showed that the foaming technology influenced greatly on the properties of foam of PBS materials. The expansion ratio had a small drop when the temperature increased. The addition of nucleator talc and foaming aids urea increased first then decreased the expansion ratio of the PBS foaming materials.

Abstract: The photocatalytic degradation of MCRR has been investigated using Ag-doped TiO₂ films as photocatalyst and sunlight as irradiation source. Ag-doped TiO₂ films can significantly accelerate the degradation of MCRR both in distilled water and in lake water, although the efficiency in lake water was not good as in distilled water. The photocatalytic activity was affected by the number of coating cycles and the best performance was found in films prepared with five coatings. Solution pH can also significantly influence the photocatalytic degradation of MCRR, and acidic pH was more efficient for the degradation of MCRR.

Abstract: In this paper, the nanometer TiO₂ film is prepared by sol-gel method, using tetrabutyl titanate as source, ethanol as solvent. A transparent sol aging in air 30min, titanium dioxide films are prepared by using spin coating method. The BPA solution is degraded by the nanometer TiO₂ film. The photocatalytic degradation efficiency is influenced by the initial BPA concentration, the solution pH, irradiation time and the UV irradiation intensity. The short degradation time shows that the nanometer TiO₂ film can be used as an easy and efficient method to degrade the BPA solution.

Abstract: This paper studies the effects of reaction time, temperature, initial concentration of phosphate, pH and organic matter concentration on the adsorbent of briquette ash to phosphate. The results indicate that the briquette ash shows many cavities. The isothermal adsorption process of phosphate on briquette ash can be fitted by Langmuir equations with high correlation coefficient, the maximal adsorption amount is 1250mg·kg^-1 according to Langmuir equations. The adsorption amount increases as pH increases in the condition of acidity but decrease in alkalescency, the small molecule organic could reatrain the adsorption of phosphate but strengthen the release of saturation phosphate of briquette ash. The adsorption can be influenced by the adsorbent amount, the unit adsorption amount increases and then decreases slowly.

Abstract: The nanometer TiO₂ film is achieved by sol-gel method, and using tetrabutyl titanate as source, ethanol as solvent, acetic acid as complexing agent. The nanometer TiO₂ film is prepared by using spin coating method. Methylene blue solution is degraded by the nanometer TiO₂ film. The photocatalytic degradation efficiency is influenced by the nanometer TiO₂ film amount, irradiation time, the UV irradiation intensity and solution temperature. The short degradation time shows that the nanometer TiO₂ film can be used as an easy and efficient method to degrade methylene blue solution.