نتایج جستجو برای: langmuir hinshelwood model
تعداد نتایج: 2108823 فیلتر نتایج به سال:
Hydrogenation of six model feeds containing three-, two-, and one-ring aromatic compounds was investigated to gain insights into the aromatic hydrogenation reaction chemistry over a commercial NiMo catalyst under practical reaction conditions. The hydrogenation reactivity of the aromatic compounds followed the following order: phenanthrene ∼ two-ring aromatics . one-ring aromatic. Comparison wi...
Mechanisms for epoxide reduction with hydrazine on a single-layer graphene sheet are examined using quantum mechanical calculations within the framework of gradient-corrected spin-polarized density-functional theory. We find that the reduction reaction is mainly governed by epoxide ring opening which is initiated by H transfer from hydrazine or its derivatives. In addition, our calculations sug...
hydrothermal synthesis of nickel-chitosan hybrid has been accomplished using ni(ch3coo)2,4h2o, chitosan and water as starting material, template and solvent respectively, followed by calcination at 800 and 900˚c to provide nanoporous nio800 and nio900. the solid products were characterized by x-ray diffraction (xrd), nitrogen adsorption-desorption, scanning electron microscopy (sem) and four...
The ubiquity of oleic acid (OA) renders it a poster child for laboratory investigations of environmental oxidation chemistry. In the current study, mechanistic details of the oxidation of OA by hydroxyl radicals at the air-water interface are investigated using field-induced droplet ionization mass spectrometry (FIDI-MS). Products from OH oxidation of both unsaturated and saturated carbon atoms...
Bilirubin (BR) is a protective antioxidant; however, when its conjugation and excretion are impaired, as in neonatal and hereditary jaundice, BR accumulates and may cause severe neurotoxicity. Here, we report a novel mechanism for ZnO nanoparticle (NP)-sensitized BR degradation via defect-mediated nonradiative energy transfer pathway. Among different sizes and shapes, ZnO particles with diamete...
The photocatalytic degradation of a macrolide (tylosin) has been studied using immobilized titanium dioxide as photocatalyst in a laboratory reactor under UV illumination (365 nm). The degradation of the antibiotic and of the reaction intermediary product was monitored by UV spectrophotometry and HPLC. Three photocatalysts (P25 from Degussa and PC105 and PC500 from Millennium) immobilized on gl...
A carbon foam using coal tar pitch as precursor was prepared and investigated as support for titanium oxide for the photocatalytic degradation of phenol. The performance of the carbon foam/titania composite was compared to those of unsupported titania and other activated carbon composites from the literature. The photodegradation rate of phenol over the catalysts under UV illumination was fitte...
In this paper, we show that the onset potential for CO oxidation electrocatalyzed by ∼2 nm dendrimer-encapsulated Pt nanoparticles (Pt DENs) is shifted negative by ∼300 mV in the presence of a small percentage (<2%) of Cu surface atoms. Theory and experiments suggest that the catalytic enhancement arises from a cocatalytic Langmuir-Hinshelwood mechanism in which the small number of Cu atoms sel...
the kinetic of fischer-tropsch synthesis over a co-precipitated fe-ce catalyst was investigated in a fixed bed micro reactor. experimental conditions were varied as follow: reaction pressure 1-15bar, h¬¬¬2/co feed ratio of 1-3 and space velocity of 3600-5400 h-1 at the temperature range of 270-310°c. 4 models according to the langmuir-hinshelwood-hougen-watson (lhhw) type rate equation were der...
This study evaluated the performance of a photoreactor packed with TiO2/glass, TiO2 immobilized on glass beads, initiated by UV irradiation, denoted as UV/TiO2/glass, to decompose di-n-butyl phthalate (DBP) in an aqueous solution. The photodegradation rate of DBP by this UV/TiO2/glass process was found to obey pseudo first-order kinetics represented by the Langmuir-Hinshelwood model. The experi...
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