Papers by Keyword: Methyl Orange (MO)

Abstract: TiO₂/Fe₂O₃ nanocomposite was fabricated by a hydrolysis-precipitation approach, with TiCl₄ as precursor and Fe₂O₃ as support. The crystal phase, diameter and morphology of the sample particle were characterized by X-ray diffraction, transmission electron microscope. The results show that the samples are composed of haematite and rutile. The morphology and diameter of rutile particle, coating effect and weight percentages of haematite and rutile are related to the preparing temperature and molar ratio of Fe/Ti. The photocatalytic activity of the prepared photocatalyst was estimated in an aqueous solution at ambient temperature of 303K. The results imply that the photocatalytic activity of the sample is higher than that of phase pure rutile, related to Fe/Ti molar ratio and its preparing temperature. These results can be attribute to the microsturcture of the sample. A synergistic effect exists between titania and haematite in the nanocomposite.

Abstract: TiO₂/CNTs nanocomposites with different Ti/C molar ratios were prepared by a sol-hydrolysis method at 368 K, using titanium tetrachloride as a precursor and nitrified carbon nanotubes as a support. The crystal phase, morphology and microstructure of the sample were characterized by X-ray Diffraction (XRD) and High-Resolution Transmission Electron Microscope (HRTEM). The photocatalytic activity of the samples was performed by methyl orange in aqueous solutions under UV light.The supernatant liquid of methyl orange during degradation was determined by using an UV-vis spectrophotometer (UV-vis). XRD results show that the crystal phases of the sample are composed of carbon nanotubes, anatase and rutile. HRTEM results show that the average diameter of oval titania is about 4.2 nm, and it decorates on the surface of carbon nanotubes uniformly. UV-vis results show that the photocatalytic activity of the TiO₂/CNTs nanocomposite with the optimum Ti/C molar ratio is much higher than that of P25. These results indicate that a synergistic effect exists between titania and carbon nanotubes in the nanocomposite.

Abstract: The in-suit Dy-doped titanium dioxide nanotubes arrays were prepared by anodic oxidation method using Dy (NO₃)₃·6H₂O and pure Ti sheet. The sample was characterized by SEM, XRD and XPS for its size and structure. The photocatalytic properties of nanotubes arrays were researched by using methyl orange as target degradation under the visible light. The results showed that the catalytic activity of Dy-doped titanium dioxide nanotubes arrays was 72% under visible light. The catalyst has hight stability and potential industrial applications.

Abstract: The ZnO particles with mesoporous and lamellar structure were synthesized in the method of precipitation, using zinc acetate as precursor. The ZnO particles were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and N2 adsorption–desorption measurements. The photoactivity of as-prepared ZnO particles was evaluated by degradation experiment of methyl orange aqueous solution. The results showed the obtained ZnO particles were irregular polygons with lamellar structure, and the particle size was in the range of 50 nm to 300 nm. According to XRD and N2 absorption results, ZnO particles were pure and integrated crystals with high crystallinity, and adsorption-desorption isotherms correspond to the typical type IV isotherm with a hysteresis loop of type H3, which showed ZnO particles had mesoporous structure with slit pore shape. The ZnO particles had high photocatalytic activity, the maximum degradation rate of methyl orange aqueous solution can reach 99%. When reused for the fifth time, the photocatalytic activity of ZnO particles was similar with the fresh ones, and recycled for the tenth time, the degradation rate of methyl orange aqueous solution still standed by 84.7%.

Abstract: The TiO2 particles were synthesized in the solvothermal method, and they were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis and differential thermal analysis (TG-DTA) and the N2 adsorption–desorption measurement. The photocatalytic property of as-prepared TiO2 particles was evaluated by the degradation experiment of methyl orange aqueous solution. Results indicated that TiO2 nanoparticles were the combination of anatase-TiO2 and rutile-TiO2 crystals with integrated crystals form and high crystallinity, which may be helpful for stabilizing the anatase and improving the photocatalytic activity. The adsorption-desorption isotherms was the typical type IV isotherm with a clear H2-type hysteresis loops in the desorption branch. The results showed mesoporous TiO2 particles had the average pore diameter of 3.587 nm, the average specific surface areas of 270.342 m2/g, and the average pore volume of 0.259 cm3/g. Meantime, the as-prepared TiO2 particles had good thermal stability and high photocatalytic activity, when being irradiated for 120 min, the degradation rate of the methyl orange aqueous solution could be up to 98.27%.

Abstract: ZnO crystals with different morphologies were successfully prepared via a simple solution route at low temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis diffuse reflectance spectra (UV-Vis DRS) were used to characterize the products. Photocatalysis of the as-prepared ZnO crystals was evaluated by degradation of methyl orange in an aqueous solution exposed to ultraviolet light. Results suggested a close relationship between the photocatalytic activity and the particle morphology and size.

Abstract: Different environmental remediation materials were prepared by using Cetyltrimethylammonium Bromide (CTMAB) and/or TiO₂ to surface-modify expanded perlite (EP). Photocatalytic degradation of Methyl Orange in polluted water by these materials (CTMAB-EP, TiO₂/CTMAB-EP, TiO₂-EP and EP), adsorption/ degradation kinetics and relevant factors affecting degradation effects were studied. The results showed that EP had little ability to remove Methyl Orange in water, while EP modified with CTMAB and/or TiO₂ could remove Methyl Orange (MO) significantly, and TiO₂/CTMAB-EP treatment showed the highest removal rate in all treatments. Removal effects of the materials were influenced by dosage of material, shaking time and initial concentration of MO in water. These results indicated that nanoTiO₂/CTMAB-Expanded perlite can be used as a new and promising environmental remediation material in efficient removal of organic pollutant from environment.

Abstract: A La-doped Cu₁₁O₂ (VO₄)₆ photocatalyst with optimum La/Cu molar ratio of 4% was prepared by sol-gel method. XRD,SEM and EDX have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of MO under the UV-light, the as-prepared La/ Cu₁₁O₂ (VO₄)₆ exhibits higher activity than the pure Cu₁₁O₂ (VO₄)₆. It found that the La/ Cu₁₁O₂ (VO₄)₆ prepared with the La/Cu molar ratio of 4% and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 92.45% or so in 60min under 20W UV light.

Abstract: Cu₁₁O₂ (VO₄)₆ powders have been synthesized by complexing Sol-Gel method using citric acid as chelate, calcined at different temperature without using any template. Techniques of X-ray diffraction (XRD) and scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under UV-light. It revealed that temperature values can influence significantly on the morphologies and structures of the products.It also found that the sample prepared with the molar ratio of citric acid to metal inons be 2:1, pH=7 and calcinated under 500°C for 4 hours was pure triclinic Cu₁₁O₂ (VO₄)₆ phase.In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 78.9% or so in 60min under 20W ultraviolet lamp.

Abstract: Hollow cubic TiO₂ particles were synthesized using cubic Cu₂O particles as hard templates, and the hydrolysis of tetrabutyl titanate (TBOT). The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Vis spectrometer, respectively. The results show that the prepared TiO₂ is composed of anatase TiO ₂, and has a stronger absorption in the range of 300-400nm wavelengths in its UV-Vis spectroscopy. Experiments were carried out using a methyl orange solution as a model to evaluate the photocatalytic activity of hollow cubic TiO₂ particles. The effects of catalyst dosage, initial concentration and pH of methyl orange solution on the degree of photodegradation have been investigated. It’s found that the hollow cubic TiO₂ particles have a good photocatalytic property. And the degradation rate of the methyl orange, after methyl orange solution (5mg/L) containing hollow cubic TiO₂ particles (0.5g/L) is irradiated by 125W ultraviolet light for 120 minutes, is 95%.