Xiu Fang Zhang

Constructing TiO2/Gr with Rapid Electrons Transfer for Efficiency Photocatalysis

TiO2/Gr powders were fabricated by hydrothermal method. Their micro-structure was characterized by transmission electron microscopy (TEM). The results revealed TiO2 particles anchored on the Gr sheets. DRS analysis indicated there was an obvious red shift of the absorption edge of TiO2/Gr compared to that of TiO2. The experiment of photocatalytic degradation of Rhodamine B (RhB) showed that the degradation rate with TiO2/Gr was 2.40 times as much as that with TiO2. The enhanced photocatalytic performance was firstly attribSubscript textuted to the rapid transfer of the photogenerated electrons from TiO2 to Gr, which could increase the charge carrier separation, limit their recombination, and enhance the photocatalytic efficiency. Furthermore, the extended light absorption range may also contribute to the enhanced photocatalytic performance.

Preparation and Characterization of SiO2-WO3 Composite Aerogel by Ambient Pressure Drying Process

Using sodium tungsten and industrial water glass as raw materials, SiO2-WO3 composite aerogels were prepared by ambient pressure drying process. The hexamethyldisilazane(HMDSZ)/hexamethyldisiloxane(HMDSO)/hexane mixing solution was used to modify the sol-gel-derived SiO2-WO3 wet gel. The microstructure, morphology and pore characteristics of the obtained SiO2-WO3 composite aerogels were investigated by XRD, SEM, FTIR and BET N2 adsorption-desorption analysis. The adsorption/photocatalytic degradation for Rhodamine B of SiO2-WO3 composite aerogel was investigated. The results indicate that mesoporous SiO2-WO3 composite aerogel with specific surface area 660.8 m2/g and pore volume 1.94 cm3/g could be prepared by using HMDSZ/HMDSO/hexane mixing solution to modify the wet gel. The obtained SiO2-WO3 composite aerogels have good adsorption/photocatalytic degradation for Rhodamine B than that of pure WO3 aerogel.

Hydrothermal Synthesis of ZnO/Zn Composites with Enhanced Photocatalytic Performance

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.

Preparation of TiO2/AC and Investigation of its Photocatalytic Activity

TiO2/AC composite was prepared by sol-gel method. The effect of annealed temperature and loading (or doping) ratio of AC on photocatalytic performances of TiO2/AC composite was explored. The optimum preparation conditions were 400 °C (annealed temperatur) and 2% (loading (or doping) ratio of AC). The experimental results of MB removal showed that the photocatalytic ability of TiO2/AC composite prepared under optimum conditions was higher than that of TiO2, which could be attributed to strong adsorption capacity, efficient photoproduced electron-hole separation, and higher light response.

Degradation of Reactive Brilliant Blue KN-R by Zero-Valent Iron/Activated Carbon Combined with Ultrasound

The treatment of Reactive Brilliant Blue KN-R in wastewater was conducted by using the zero-valent iron/activated carbon (Fe0/AC) combined with ultrasound (US). Although ultrasound alone had a little effect on the KN-R degradation and Fe0/AC had some disadvantages when it acted on the KN-R, the efficiency of the degradation was dramatically enhanced which used the combination of Fe0/AC /U.S. that also could eliminate the shortcomings. The decolorization percentage was nearly up to 100% and the COD removal rate has approached to 87.38%.

Oxidative Degradation of Azo Dye Reactive Red 2BF by Potassium Ferrate

The oxidative degradation of azo dye Reactive Red 2BF in aqueous solution by using potassium ferrate (Ⅵ) was studied. The initial concentration of wastewater 100 mg/L, pH 4.0, reaction time 20 min, and the dosage of potassium ferrate was 0.9 g/L. Under the optimal conditions, the decolorizing rate of Reactive Red 2BF and the COD removal rate were 99.9% and 73.3%.

Response of Urban Roadside Greening Plant Exposed to Automobile Exhaust Pollution

The changes of chlorophyll, malondialdehyde(MDA) and the catalase(CAT) activity in mature leaves of a common urban roadside greening plant------- Buxus sinica were studied. The results show that under automobile exhaust polluted environment, the contents of chlorophyll a, chlorophyll b and total chlorophyll decreased while the content of MDA and the activity of CAT increased. These changes have correlation with the automobile exhaust pollution.

Microwave Assisted Hydrothermal Synthesis and Characterization of N, S Co-Doped ZnO Photocatalyst

The N, S codoped ZnO was synthesized by microwave assisted hydrothermal method. The N, S codoping narrowed the band gap of ZnO (formed impurity states in the band gap), hence shift light response to range of visible light. Furthermore, the doped ZnO exhibits significantly higher photocatalytic activity than that of pure ZnO for degradation of reactive brilliant blue KN-R aqueous solution under simulative solar irradiation.

Preparation of Porous BiVO4 and its Photocatalytic Degradation of MB under Simulated Sunlight

Porous BiVO4 was fabricated by hydrothermal method with P123 as the template. SEM revealed there were many pores in porous BiVO4. DRS analysis indicated that the absorbance of BiVO4 was enhanced by constructing porous structure. The results of MB removal showed that the degradation rate with porous BiVO4 was 3.05 times as much as that with BiVO4. The enhanced photocatalytic performance was attributed to the enhanced absorbance ability and promoted surface reactions.

Fabrication Porous Ag/BiVO4 Film for Efficient Degradation of Phenol under Visible Light

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.