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61.
撞击流反应-沉淀法制取纳米二氧化钛影响因素的实验研究 总被引:2,自引:0,他引:2
采用浸没循环撞击流反应(SCISR),通过四氯化钛快速水解沉淀法制备了纳米二氧化钛,研究了浓度、温度、转速、中和时间、煅烧温度以及煅烧时间等因素对纳米二氧化钛粒径的影响。 相似文献
62.
MCM-41 materials were synthesized using alkyl(decosane, dodecyl)trimethyl ammonium bromide as structure directing surfactants. X-ray diffraction (XRD) analysis and nitrogen adsorption measurements reveal that the pores are hexagonal with tunable textural properties through the choice of surfactant and experimental condition. Poly(diphenylamine), PDPA was entrapped into the pores of MCM-41 by initial sorption of diphenylamine (DPA, monomer) in a medium (napthalein sulfonic acid) that provides self-assembling of DPA inside the pores and subsequent oxidative of polymerization with peroxydisulphate. Clear presence of an additional peak (around 9-10°) in XRD pattern for the DPA loaded MCM-41 provides evidence for self-assembled structure. Upon polymerization the self-assembly of DPA molecules resulted tubular PDPA inside the pores of MCM-41. PDPA thus formed shows different electronic property than the PDPA prepared by conventional method. XRD and FTIR spectroscopic analysis of PDPA loaded MCM-41 clearly informs that PDPA are entrapped in channels of MCM-41. 相似文献
63.
Yoichi Tominaga 《Electrochimica acta》2005,50(19):3949-3954
We have synthesized mesoporous silica (MPSi) as a novel type of inorganic filler for polyether-based electrolytes and have characterized the effect of addition on ionic conduction. Both poly(ethylene oxide) (PEO) and PMEO composites filled with MPSi showed higher ionic conductivity than the original and the composites filled with particle silica (pSiO2). It was considered that the increase is caused by the difference in the surface area between MPSi and pSiO2. In the PEO composites, the addition of MPSi gave rise to the reduction of crystal PEO and crystalline complex domains. The glass transition temperature of the PMEO composites increased with the addition of the MPSi, in spite that the conductivity increased with increasing the filler contents. It has been suggested that the Lewis acid-base interactions between ions, ether chains and filler surface strongly affect on the ionic conduction in the composite electrolytes. 相似文献
64.
Juan M. Coronado Javier Soria José Carlos Conesa Ricardo Bellod Cristina Adán Hiroyuki Yamaoka Vittorio Loddo Vincenzo Augugliaro 《Topics in Catalysis》2005,35(3-4):279-286
A continuous photoreactor, working in a total recycle mode and irradiated by a low-pressure Hg lamp, has been used to study
the bactericidal effect of a photocatalyst, formed by TiO2 embedded in SiO2 fibres, on Legionella pneumophila and a consortium of common gram-negative aerobic bacteria: (Escherichia coli, Klebsiella sp., Pseudomona sp. and Proteus sp.) in water. The kinetic modeling of the inactivation process, carried out with the measured values of viable bacteria
concentration at the outlet of photoreactor, evidenced that for each pass inside the photoreactor the ratio between the outlet
and inlet cell concentrations was of order of 0.01 for the inactivation of L. pneumophila. For the other aerobic bacteria, which are usually taken as reference in photocatalytic bacteria inactivation studies, this
ratio was of order of 0.3 for the first hour of illumination, while upon prolonged irradiation (up to 9 h) this ratio increased
to 0.7. Several factors inducing this latter decrease of efficiency are possible, as e.g. competition for photocatalytic attack
between microorganisms and organic compounds released by damaged bacteria or photoinduced alteration of a small fraction of
still viable bacteria making them less interactive with the photocatalyst. The inactivation mechanism normally proposed for
common bacteria involves an initial attack of the photogenerated radicals to the outer membrane; the consequent membrane dispersion
allows the radicals to damage the cytoplasmic membrane. The higher lethality of the photocatalytic method observed towards
Legionella: (in comparison to the other aerobic bacteria) is explained considering that the radicals attack the Legionella secretion system, which is adapted for high virulence and would become activated for and through adhesion to the TiO2 surface. This attack would then be able to inactivate L. pneumophila without dispersing the outer membrane. Apart from this, the water flow through the catalyst fibres can facilitate the bacteria
transport towards the anatase surface, and additionally the generated shear stress may help adhesion, at least for some bacteria
as E. coli, contributing further to improve the photokilling efficiency; both factors may contribute to the efficiency of this photoreactor
configuration. 相似文献
65.
《Ceramics International》2022,48(12):16997-17008
Effective design and fabrication of novel visible light-oriented photocatalysts is an existing challenging task that requires further dedicated efforts, and it has been always a main concern among the scientific community. This study deals with the design and fabrication of an extremely active and ultrafast ternary photocatalyst based on Ag nanoparticles, polypyrrole doped carbon black (PPy-C) and mesoporous TiO2 (m-TiO2). Sol-gel methodology along with sonication and photodeposition routes have been employed for the successful creation of the ternary framework. Ternary photocatalyst composed of uniform spherical titania nanoparticles (10–15 nm in size) perfectly intermingled with the polymeric linkage of PPy-C. Fruitful creation of unique trio photocatalyst between AgNPs, PPy-C and m-TiO2 was confirmed by XPS and XRD. FTIR analysis further supports the development of nanocomposite photocatalyst. TEM analysis showed uniform spherical m-TiO2 nanoparticles (10–15 nm in size) covered by PPy-C with compact nodes like appearance interlocked very well among each other. The newly developed Ag@PPy-C/m-TiO2 ternary photocatalyst exhibited band gap energy in desired visible range of spectra. The photocatalytic efficiency for all created photocatalysts has been evaluated taking Imidacloprid (insecticide derivative) and methylene blue (MB) dye as target pollutants. The novel Ag@PPy-C/m-TiO2 photocatalyst produced astonishing results with ultrafast removal of both Imidacloprid as well MB dye under visible light irradiation. The newly created ultrafast Ag@PPy-C/m-TiO2 photocatalyst has removed 96.0% of the insecticide Imidacloprid in only 25 min with almost ? 2.65 times more efficient than bare m-TiO2 towards the removal of insecticide derivative. The present report offers a highly encouraging and vastly talented Ag@PPy-C/m-TiO2 ternary photocatalyst, enabling the ideal management of extremely lethal and notorious chemicals. 相似文献
66.
Synthesis of structured silicon carbide materials can be accomplished using wooden materials as the carbon source, with various silicon impregnation techniques. We have explored the low cost synthesis of SiC by impregnation of carbon from wood with SiO gas at high temperatures, which largely retains the structure of the starting wood (shape memory synthesis). Suitably structured, porous SiC could prove to be an important type of catalyst support material. Shape memory synthesis (SMS) has earlier been tried on high surface area carbon materials. Here we have made an extensive study of SMS on carbon structures obtained from different types of wood. 相似文献
67.
Evgeny V. Rebrov Jaap C. Schouten 《Chemical Engineering and Processing: Process Intensification》2011,50(10):1063-1068
The article highlights new insights into production of thin titania films widely used as catalyst support in many modern reactors including capillary microreactors, microstructured fixed-bed reactors and falling film microreactors. Dip-coating of a titania sol onto a Si substrate has been studied in the range of the sol viscosities of 1.5-2.5 mPa s and the sol withdrawal rates of 0.2-18 mm/s. Different viscosities of sols were created by addition of desired amounts of nitric acid to the synthesis mixture of titanium isopropoxide and Pluronic F127 in ethanol which allowed to control the rate of the condensation reactions. Uniform mesoporous titania coatings were obtained at the solvent withdrawal rates below 10 mm/s at sol viscosities in the range from 1.6 mPa s to 2.5 mPa s. There exists a limiting withdrawal rate corresponding to a capillary number of ca. 0.01 beyond which uniform titania films cannot be obtained. Below the limiting withdrawal rate, the coating thickness is a power function of the sol viscosity and withdrawal rate, both with an exponent of 2/3. The limiting withdrawal rate increases as the solvent evaporation rate increases and it decreases as the sol viscosity increases. 相似文献
68.
69.
选取亚甲基蓝染料为降解目标物,研究了ZnO掺杂TiO2为催化剂的可见光催化反应,重点考察了ZnO的掺杂量、催化剂的添加量、溶液初始浓度、光照时间、溶液pH值对降解效率的影响。实验结果表明,在ZnO掺杂比为0.5%、ZnO掺杂TiO2的催化剂用量为10g/L、pH为8、浓度为2mg/L的亚甲基蓝100mL,白炽灯光照降解... 相似文献
70.
Meng-Liang Lin Kenji Hara Yasuhiro Okubo Masaaki Yanagi Hironobu Nambu Atsushi Fukuoka 《Catalysis communications》2011,12(13):1228-1230
The olefin epoxidation is one of the most important reactions in chemical industry. Metal oxide supports often cause drawbacks in catalytic activity and selectivity, which has been overcome by introducing hydrophobic organic groups onto the oxide supports. The present study utilizes ordered mesoporous carbon (CMK-3 and CMK-1) as structurally defined hydrophobic catalyst support. Well-dispersed tantalum oxides supported on the ordered mesoporous carbon were prepared. Their application in catalytic epoxidation of cyclooctene demonstrates that the tantalum oxide catalysts on the ordered mesoporous carbon supports show higher performances than those of the catalysts supported on activated carbon and ordered mesoporous silica SBA-15. 相似文献