Authors: Jae Hyun Park, Seung Young Lee, Dal Hee Bae, Nam Yun Lim, Jin Wook Ha
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Authors: Jin Wook Ha, Young Woong Do, Jae Hyun Park, Chul Hee Han
Abstract: Fluidized Bed Chemical Vapor Deposition (FB-CVD) method offers advantages over conventional Chemical Vapor Deposition method in coating three dimensional objects. In addition, catalysts prepared by FB-CVD method often show improved physicochemical properties. Thus, FB-CVD seems a useful method for coating TiO2 onto small beads, in view of their photocatalytic application in aqueous environment, for example. In this work, we produced TiO2 coated beads (1~2mm in diameter) of alumina, silica-gel, and glass in ~35nm thickness using FB-CVD method, and examined photocatalytic performance of TiO2 coated beads in the photocatalytic decomposition reaction of methylene blue solution. Based on the combined results of the decomposition reaction kinetics of methylene blue and FE-SEM images of the surface morphology of TiO2 coated beads, we were able to account for the photocatalytic performance with respect to characteristic features detected in the surface morphology.
663
Authors: Zhi Ping Zhu, Ting Liu, Shu Hua Xiong, Ling Ling Jing
Abstract: The nano-TiO2 photocatalysts which loaded on hollow float beads were prepared by sol-gel process. The hollow float beads as carrier was modified by H2SO4 and the TiO2 sol was obtained by tetrabutyl titanate, the modified hollow float beads was added into TiO2 sol, the TiO2 gel was obtained, then calcined at 450°C, 500°C, 550°C respectively and obtained as-produced samples. Their property were characterized by TGA, XRD and SEM, Their photoactivity was evaluated by the photodegradation of the trace oil from fossil-fired power plant condensate under a series of temperature（15°C~45°C）, pH value（2~14）, initial oil concentration（5mg/L） and catalysts dosage（2.500g/L, 4.000g/L, 5.000g/L, 6.000 g/L, 7.500g/L, 10.000g/L）, the experimental results showed that as temperature at 35°C, pH value at 10, catalysts dosage at 5.000g/L and calcined temperature at 500°C, the trace oil degradation rate could exceed 90% in 12 h, the catalysts could provided a efficient method to degradate the trace oil.
564
Authors: Ling Kun Guo, Jun Lv, Song Zhou, Dong Mei Wang, Zhi Xiang Zheng, Guang Qing Xu, Yu Cheng Wu
Abstract: Using TiCl4 as the titanium source, urea as the precipitating agent, nano-TiO2/fly ash beads composite materials were prepared by hydrolysis-precipitation method. The materials were characterized by SEM and XRD methods. SEM observation shows that the surface of beads have been loaded a uniform TiO2 film. XRD results shows that TiO2 films have the main phases of anatase and rutile mixed crystal structure. The effect of surface activation process of fly ash beads on TiCl4 solution hydrolysis rate was studied. The influence of calcination temperature on the microstructure and properties of composite materials was also discussed. The photocatalytic properties of the prepared materials was measured by using UV-1800 uv-vis spectrophotometer. The results show that: The composite which calcined at 500°C has a grain size of 15nm, anatase phase content of 90%, shows the best photocatalytic effect. The degradation rate of methyl orange solution can reach 95% after 2 hours irradiation (300W, Mercury lamp). Repeated experiments show that the degradation rate of composite materials still reach 80% after being used for 5 times .
440
Authors: Guang Hai Wang, Yue Zhang, Yu Feng Chen
Abstract: Hollow glass micro-beads uniformly coated by a shell of titania with thickness of 50 to 300 nm, were fabricated by wet chemical methods. The pigments were dispersed in silica coatings，then the pigmented coatings were deposited on quartz substrates by sol-gel spin-coating method with a thickness of about 80 µm. SEM, TEM and FT-IR techniques were used to characterize the microstructure and properties of the coatings. FT-IR indicated average infrared transmittance of coatings containing the core-shell particles was significantly lower than that of coatings containing no functional particles or containing hollow glass micro-beads, when the volume fraction of core-shell particles was just 5%. In view of its low infrared transmittance, pigmented silica coatings may find applications in high-temperature heat-insulating materials for reducing radiation heat transfer.
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