Advanced Materials Research Vols. 518-523

Abstract: An erbium ion doped Bi₁₂TiO₂₀ was prepared by a simple method. XRD and UV-vis diffuse reflectance spectroscopy (DRS) were used to characterize the prepared photocatalysts. The results indicated that the erbium ion dopant had no influence on the phase of Bi₁₂TiO₂₀ and can extend its visible light adsorption spectra. Photocatalytic activities of the prepared samples were evaluated using methyl orange as a model organic compound. The results showed that doping with 0.5 mol% Er³⁺ can significantly improve the photocatalytic performance of Bi₁₂TiO₂₀.

Abstract: We have successfully deposited anatase TiO₂ thin films at room temperature on polycarbonate substrates by RF magnetron sputtering. Four deposition parameters including RF power, sputtering pressure, argon/oxygen ratio and deposition time were employed to realize the photocatalytic activities of TiO₂ films. The orthogonal array and analysis of variance (ANOVA) were adopted to determine the performance of the deposition process. The RF power was found to be the major factor affecting the photocatalytic properties. An increase in RF power could be improved the deposition rate, contact angle, and MB absorbance.

Abstract: In this paper, it was investigated the changes of structure of sepiolites under different conditions of acid treatments and heat treatments using fourier transform infrared spectroscopy(FTIR). At the same time, through the tannin adsorption experiments, it was studied the changes adsorption properties of sepiolites by acid treatments and heat treatments. The H2SO4 treatment was found to be more effective for the removal of tannin than HCl and HNO3 treatments. With increasing the acid concentration and acid treatment time of H2SO4, the removal rates and adsorption capacity of tannin by sepiolites were first increased and then decreased. The removal rates and adsorption capacity were 61.0% and 23.7mg/g when the acid concentration was 4.0mol/l. And the removal rates and adsorption capacity were 62.5% and 24.3mg/g when the acid treatment time was 16 hours. The calcinations treatment exhibited significant effects on the adsorption of tannin. The removal rates and adsorption capacity were 77.9% and 30.8mg/g when the calcined temperature was 400°C. However, when the calcined temperature was 700°C, the removal rates and adsorption capacity were only 54.1% and 20.8mg/g.

Abstract: Porous BiVO4 film was fabricated by templating procedure with polystyrene (PS) balls as the template. Ag particles were loaded on the porous BiVO4 film by photoreduction technique. SEM revealed there were many pores in the film and Ag particles were successfully loaded on the porous BiVO4 film. XRD analysis indicated that the chemical state of Ag particles was metallic Ag. The experiment of photocatalytic degradation of phenol showed that the degradation rate on porous Ag/BiVO4 film was 4.74 times as much as that on the BiVO4 film. The enhanced photocatalytic performance was firstly attributed to the rapid transfer of the photogenerated electrons from BiVO4 to Ag, which could increase the charge carrier separation, limit their recombination, and enhance the photocatalytic efficiency. Furthermore, porosity of the photocatalyst may enhance diffusion process and decrease diffusion resistance of the reactants throughout the channels in the photocatalyst, and thus improves the surface reactions.

Abstract: Developing photocatalysts with specific morphology promises good opportunities to discover the geometry dependent properties. Porous and spherical shaped superstructure of ZnAl₂O₄ was successfully synthesized by a facile wet chemical solution-phase method. Their surface morphology and structure were investigated by X-ray powder diffraction, scanning electron microscopy, energy dispersive spectra and Brunauer-Emmet-Teller N₂ gas adsorption-desorption isotherms. The optical property of the ZnAl₂O₄ nanospheres were studied by UV-vis diffuse reflectance spectroscopy. The ZnAl₂O₄ nanospheres exhibited a good photocatalytic activity in degrading rhodamine B.

Abstract: ZnO hierarchical microstructures with uniform flower-like morphology were successfully prepared on a large scale through a carboxymethylcellulose sodium (CMC)-assisted hydrothermal route. X-ray powder diffraction (XRD) measurement confirmed the formation of wurtzite-structured ZnO phase. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis indicated that the as-prepared ZnO sample was composed of numerous three dimensional flower-like microstructures, each of which was assembled by nanosheets with the thickness of about 40 nm. High-resolution transmission electron microscopy (HRTEM) measurement revealed the good crystallinity nature of the ZnO nanosheets in the flower-like microstructures. The formation mechanism and photocatalytic property of the as-prepared flower-like ZnO hierarchical microstructures were studied.

Abstract: ZnO/Zn composites photocatalysts were prepared by hydrothermal method using Zn powder as raw material, and the morphology, structure, and photocatalytic performance of composites were investigated. The results showed that the ZnO nanoparticles were produced at the surface of Zn metal powder during hydrothermal process. The thickness of ZnO outer layer (internal metal-semiconductor interfaces) can be controlled by varying hydrothermal treatment time. The resulting ZnO/Zn composites exhibit significantly higher photocatalytic activity than that of pure ZnO for degradation of anthraquinone dye (reactive brilliant blue KN-R) aqueous solution under ultraviolet light irradiation. The enhancement of photocatalytic performance of ZnO/Zn composites can be attributed to the formation of internal metal-semiconductor interfaces. The designed fabrication procedure is simple, feasible, and universal for a series of oxide/metal with controlled microstructure and improved performances.

Abstract: Photocatalytic Oxidative-Extraction Desulfurization (Photo-cat-EODS) of thiophene, the main sulfur-containing compound of catalytic cracking (FCC) gasoline, has been investigated in heterogeneous photocatalysis process using WO3/ZnO composite as photocatalyst and air was used as the oxidant. Extraction process was also employ followed by the photocatalytic oxidative process to remove the oxidative products using acetonitrile as the extractant. Furthermore, orthogonal experiments method was used to optimize the processing parameters.

Abstract: Polyurethane-polyvinylidene fluoride (PU-PVDF) hollow fiber blend membrane prepared by melting, spinning and drawing processes was used to treat lake water in a submerged coagulation-microfiltration (SCMF) process. This novel membrane is characterized by its elastic pore size increase with the pressure increase; therefore, the backwashing step could effectively remove the depositions stuck in membrane pores. Compared to the system using polyvinylidene fluoride (PVDF) hollow fiber membrane, the membrane anti-fouling ability was stronger in the system using PU-PVDF blend membrane, and the transmembrane pressure increased more slowly at a fixed permeate flux. Organic matters were removed comparably for both membranes during the first 3 h treatment, but those with benzene ring structures were susceptibly restricted by PU-PVDF blend membrane as the filtration went on. The turbidity removal was stable in the PU-PVDF system with an average of 97%, and was slightly higher than that in the PVDF system. The outstanding anti-fouling ability and excellent pollutant removal performance make the PU-PVDF hollow fiber blend membrane a better candidate for the SCMF process.

Abstract: Nonstoichiometric Zinc oxide (ZnO) nanorod arrays doped Co or Ni can be easily obtained by calicining soaked ZnO nanorod arrays. More importantly, the nonstoichiometric doped ZnO nanoarrays have more effective antimicrobial than pure ZnO nanoarrays, which means we can obtain a kind of promising new effective functional nanomaterials.