Catalytic reduction of no over perovskite-type catalysts

In the present work, we have investigated the reduction of NO by propane over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxides. In addition, the reaction conditions, such as temperature, O₂ concentration, and space velocity have been varied to understand their effects on the catalytic performance. In the LaCoO₃ type catalyst, the partial substitution of Ba and Sr into A site enhanced the catalytic activity in the reduction of NO. For the La_0.6Ba (Sr)_o.4 Co_1−x Fe_xO₃ (x=0-1.0) catalyst, the partial substitution of Fe into B site enhanced the conversion of NO, but excess amount of Fe decreased the conversion of NO. The surface area and catalytic activity of perovskite catalysts prepared by malic acid method showed higher values than those of solid reaction method. The conversion of NO increased with increasing O₂ concentration and contact time. The introduction of water into reactant feed decreased the catalytic activity but the deactivation was shown to be reversible over La_0.6Ba_0.4Co_1−x ,Fe_xO₃ catalyst.     

Possibilistic support vector machines

We propose new support vector machines (SVMs) that incorporate the geometric distribution of an input data set by associating each data point with a possibilistic membership, which measures the relative strength of the self class membership. By using a possibilistic distance measure based on the possibilistic membership, we reformulate conventional SVMs in three ways. The proposed methods are shown to have better classification performance than conventional SVMs in various tests.     

Breakthrough data analysis of adsorption of volatile organic compounds on granular activated carbon

Volatile Organic Compounds (VOCs) such as methanol, ethanol, methyl ethyl keton, benzene, n-propanol, toluene, and o-xylene were adsorbed in a laboratory-scale packed-bed adsorber using granular activated carbon (GAC) at 101.3 kPa. The adsorber was operated batchwise to obtain the breakthrough curves of VOCs under the adsorption conditions such as adsorption temperatures (298–323 K), flow rates of nitrogen (60×10⁻⁶-150×10⁻⁶m³/min), GAC amount of 0.002 kg, and concentration of VOCs (3,000–6,000 ppmv). The adsorption kinetics was obtained by fitting the experimental breakthrough data to the deactivation model, combining the adsorption of VOCs and the deactivation of GAC. The adsorption isotherm, and adsorbed amount and adsorption heat of VOCs were obtained using the breakthrough curve: the former for comparison with the conventional isotherm models, the latter for correlation with the physical properties of VOCs.     

Reduction of lean NO2 with diesel soot over metal-exchanged ZSM5, perovskite and γ-alumina catalysts

The catalytic performances of metal-exchanged ZSM5, perovskite and γ-alumina catalysts for the reduction of nitrogen dioxide (NO₂) by diesel soot were investigated. The reaction tests were performed through temperature-programmed reaction (TPR), in which NO₂ and O₂ were passed through a fixed bed of catalyst-soot mixture. On the three types of catalyst, NO₂ was reduced to N₂ by model soot (Printex-U) and most of the soot was converted into CO₂. Pt-, Cu- and Co-exchanged ZSM5 catalysts exhibited reduction activities with conversions of NO₂ into N₂ of about 20%. Among the perovskite catalysts tested, La_0.9K_0.1FeO₃ showed a 32% conversion of NO₂ into N₂. The catalytic activities of the perovskite catalysts were largely influenced by the number and stability of oxygen vacancies. For the γ-alumina catalyst, the peak reduction activity appeared at a relatively high temperature of around 500 °C, but the NO₂ reduction was more effective than the NO reduction, in contrast to the results of the ZSM-5 and perovskite catalysts.     

Microwave Assisted Synthesis of Cyclic Carbonate Using Homogeneous and Heterogeneous Ionic Liquid Catalysts

A comparative study was effectuated between the catalytic performance of homogeneous and silica supported ionic liquids (SSILs) for the cycloaddition of epoxides and CO₂ under microwave irradiation by varying the reaction parameters. Compared to the classical heating mode, both catalysts showed higher activity at moderate reaction condition through microwave irradiation.     

Aliphatic polycarbonate synthesis by copolymerization of carbon dioxide with epoxides over double metal cyanide catalysts prepared by using ZnX2 (X = F, Cl, Br, I)

As means of the chemical fixation of carbon dioxide and the synthesis polycarbonates, copolymerizations of carbon dioxide with various epoxides, such as cyclohexene oxide, cyclopentene oxide and propylene oxide were investigated in the presence of double metal cyanide (DMC) catalysts. The DMC catalysts were prepared by reacting K₃Co(CN)₆ with ZnX₂ (X = F, Cl, Br, I) together with tertiary butyl alcohol and poly(tetramethylene ether glycol) as complexing reagents and were characterized by various spectroscopic methods. The DMC catalysts showed high activity for epoxides and CO₂ copolymerization to yield aliphatic polycarbonates of narrow polydispersity and moderate molecular weight.     

Enhanced performance of organic electroluminescence diodes with a 2-TNATA:C60 hole injection layer

C60-doped 2-TNATA (4,4′,4″-tris(2-naphthylphenylamino)triphenylamine) as a hole injection material and NPD (4,4′bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl) as a hole transport material are used to fabricate OLEDs via vacuum deposition process in this study. C60-doped 2-TNATA film was treated by means of thermal annealing and in situ electromagnetic field. According to AFM, SEM, XRD, and Raman spectra results, by both thermal annealing and in situ electromagnetic field treatments, the smoothened surface and the closely packed morphology of 2-TNATA:C60 film was obtained without any evidences of crystalline nature after those treatments. The treatments eventually lead to enhancing the current density and efficiency of the multi-layered ITO/2-TNATA:C60 (5% doped) (70 nm)/NPD (30 nm)/Alq₃ (50 nm)/LiF (1 nm)/Al (100 nm) devices by facilitating hole injection/transport in the multi-layered organic devices. Consequently, thermal annealing treatment for the 2-TNATA:C60 film is preferred rather than in situ electromagnetic field treatment so as to improve the overall performance of the organic light-emitting diodes in this study.     

Direct incorporation of vanadium into three-dimensional KIT-6: 1. Optimization of synthesis conditions

Three dimensional (3-D) cubic KIT-6 with directly incorporated vanadium was hydrothermally synthesized by using Pluronic P123 and n-butanol as the structure-directing mixture, tetraethyl orthosilicate (TEOS) as the silica source and NH₄VO₃ as the vanadium source. The molar composition was varied in the range of 0.017 P123/0.08–2.4 V/1.0–2.0 TEOS/1.31–1.70 BuOH/1.83–3.00 HCl/195 H₂O. The orderness of mesopore structure was estimated by X-ray diffraction, N₂ adsorption, and TEM analysis. The effects of the amount of HCl, TEOS and BuOH on the structure of KIT-6 were discussed. The time and temperature for the synthesis of KIT-6 were also optimized. The amount of vanadium content influenced the framework structure and crystallinity of the Ia3d phase significantly.     

Direct incorporation of vanadium into three-dimensional KIT-6: 2. Reactivity test for styrene oxidation

The direct incorporation of vanadium into the three-dimensional (3-D) cubic Ia3d mesostructure designated as V-KIT-6 was prepared, and the material obtained therein showed a very high specific surface area of ∼1,000 m²/g with tunable pore diameters in a narrow distribution of sizes, ∼5.7 to 6.0 nm. The coordination and nature of the V sites in V-KIT-6 were characterized by ⁵¹V-spin-echo NMR analysis. It shows that after calcination, the V⁴⁺ species are totally oxidized to the V⁵⁺ state with 4- and 6-coordinated V-O environments in a highly dispersed state with much less crystalline V₂O₅ formation. The calcined V-KIT-6 materials showed excellent catalytic activity in the direct oxidation of styrene using tert-butyl hydroperoxide (TBHP) as an oxidant.     

Absorption of carbon dioxide into aqueous colloidal silica solution with different sizes of silica particles containing monoethanolamine

Carbon dioxide was absorbed into an aqueous nanometer-sized colloidal silica solution in a flat-stirred vessel at 25 °C and 101.3 kPa to measure the absorption rate of CO₂. The concentrations of silica were in the range of 0–31 wt% and the sizes were 7, 60, and 111 nm. The solution contained monoethanolamine (MEA) of 0–2.0 kmol/m³. The volumetric liquid-side mass transfer coefficient (k _L a) of CO₂ was correlated with the empirical formula representing the rheological property of silica solution. The use of the aqueous colloidal silica solution resulted in a reduction of the absorption rate of CO₂ compared with Newtonian liquid based on the same viscosity of the solution. The chemical absorption rate of CO₂ was estimated by film theory using k _L a and physicochemical properties of CO₂ and MEA.