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排序方式: 共有1177条查询结果,搜索用时 46 毫秒
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R. Chaiyont C. Badoe C. Ponce de León J. L. Nava F. J. Recio I. Sirés P. Herrasti F. C. Walsh 《化学工程与技术》2013,36(1):123-129
A film of iridium and tin dioxides doped with antimony oxide (IrO2‐SnO2‐Sb2O5) was deposited onto Ti mesh and plate substrates by the Pechini method. The electrode surface morphology and composition were characterized by SEM‐EDS. The ternary oxide coating was used for the anodic oxidation of methyl orange (MO) azo dye. Linear sweep voltammetry was used to identify the electrode potentials that favour MO degradation. Batch electrolyses were then carried out at a constant electrode potential of 1.5, 1.75 and 2.0 V vs. SHE using either a three‐electrode batch cell or a flow reactor. The dye solutions were totally decolorized via reactive oxygen species, such as ?OH, H2O2 and O3 formed in situ from water oxidation at the Ti/IrO2‐SnO2‐Sb2O5 surface. 相似文献
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The St. Lawrence River near Cornwall Ontario is affected by industrial mercury contamination of sediments and biota. It has been suggested that pulp and paper mill effluents may stimulate bacterial mercury methylation in these sediments, leading to contamination of aquatic biota. To test this hypothesis, we examined sediment–porewater dynamics of total mercury (THg) and methyl mercury (MeHg) at a site with high concentrations of wood fibers from a pulp and paper mill effluent and a nearby reference site with low wood fiber content. Dissolved phase THg (THgdiss) and MeHg (MeHgdiss) in porewater profiles showed that 38 ± 30.9% (SD) of THg in porewaters was in the methylated form regardless of wood fiber content. MeHgdiss and THgdiss concentrations were homogeneous between porewater and overlying water, indicating (a) that there is minimal net diffusion of MeHgdiss and THgdiss and (b) that redox-dependent processes such as sulfate reduction and Fe reduction were not associated with MeHgdiss distribution in these sediment profiles. MeHg and THg in solid phase showed coincident subsurface peaks at depths > 40 cm suggesting either that historical deposits of MeHg on particles (MeHg(p)) are preserved in deep sediments, or that Hg methylation is active in deep sediments. 相似文献
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梁锦海 《化学工业与工程技术》2013,(6):15-18
为了探索优化甲基氢化苯酐的工业化生产技术,考察了单套产能7.5kt/a甲基四氢苯酐和单套产能2.5kt/a甲基六氢苯酐生产装置的试运行情况。结果表明:提高单套设备的生产能力能降低原材料单耗,接近理论单耗值。分析了甲基氢化苯酐的国内外生产、消费现状及未来几年的发展趋势。 相似文献
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Ertan Alptekin 《Fuel》2009,88(1):75-80
Characterizing of the fuel properties of diesel fuels, alternative fuels and their blends can assist the researchers who work on alternative fuels for diesel engines. Therefore, in this study, methyl esters were produced from five edible vegetable oils (sunflower, soybean, canola, corn and cottonseed) and blended with two different diesel fuels at 2%, 5%, 10%, 20%, 50% and 75% on a volume basis to characterize the key fuel properties of the blends such as density, viscosity, pour point, distillation temperatures and flash point. The results showed that the fuel properties of the blends were very close to those of diesel fuels at low concentrations upto 20% of methyl esters. 相似文献
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Upendra A. Joshi James R. Darwent Humphrey H. P. Yiu Matthew J. Rosseinsky 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(8):1018-1023
BACKGROUND: This research investigated the effect of platinum (Pt) on the reactivity of tungsten oxide (WO3) for the visible light photocatalytic oxidation of dyes. RESULTS: Nanocrystalline tungsten oxide (WO3) photocatalysts were synthesised by a sol‐gel process and employed for the photocatalytic degradation of Methyl Orange under visible light. For comparison commercial bulk WO3 materials were also studied for the same reaction. These materials were fully characterised using X‐ray diffraction (XRD), UV‐visible diffuse reflection spectroscopy and transmission electron microscopy (TEM). The photocatalytic oxidation of iso‐propanol was used as a model reaction to follow the concomitant reduction of molecular oxygen. No reactions occured in the absence of platinum, which is an essential co‐catalyst for the multi‐electron reduction of oxygen. The platinised WO3 catalysts were stable for multiple oxidation–reduction cycles. The results from the catalytic activity measurements showed that platinised nanocrystalline WO3 is a superior oxidation photocatalyst when compared with bulk WO3. Methyl Orange was completely decolourised in 4 h. CONCLUSIONS: The enhanced performance of nanocrystalline Pt‐WO3 is attributed to improved charge separation in the nanosized photocatalyst. Platinum is an essential co‐catalyst to reduce oxygen. This photocatalyst could be applied to the treatment of organic pollutants in wastewater, with the advantage of using visible light compared with the widely studied TiO2, which requires UV light. Copyright © 2011 Society of Chemical Industry 相似文献
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Augustine E. Ofomaja Emmanuel E. UkpeborStephen A. Uzoekwe 《Biomass & bioenergy》2011,35(10):4112-4123
Determination of the overall rate controlling step in the biosorption of Methyl violet dye onto a new biosorbent, palm kernel fiber has been determined. Pseudo-second-order model described the kinetics over the whole contact time period for the effect of initial concentration and temperature. Using the Wu’s approaching equilibrium factor, Rw, it was observed that the time for the switch from initial biosorption to intraparticle diffusion is affected by initial concentration and temperature. A comparison between the activation parameters of film diffusion, pseudo-second order ion exchange and intraparticle diffusion revealed that film diffusion is the overall slowest step in the biosorption process. Temperature increased the biosorption capacity but reduced slightly the rate of intraparticle diffusion, indicating that the biosorbent surface was activated by temperature which limited the diffusion of Methyl violet molecules into the interior of the biosorbent. A multistage process design to minimize mass and contact time was done. 相似文献
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