• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.326-331
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• 2017

Castor oil can be used as a useful raw material for chemical industries such as intermediates of surfactants through hydrogenation reaction. In this study, effects of the preparation method and pretreatment condition on the nickel catalyst for the hydrogenation of castor oil were investigated. The nickel catalyst was supported on the silica carrier by the precipitation method with different Ni contents, solution pH values, and precipitants. Repeated pretreatments of oxidation and reduction cycles were then carried out. The activity of the nickel catalyst was measured by comparing the iodine value of the castor oil. The dispersion of nickel on the catalyst was analyzed by X-ray diffraction (XRD), $N_2$ adsorption-desorption, and transmission electron microscopy (TEM). The activity of nickel catalyst was also compared by CO oxidation experiments. The redispersion of nickel occurred on the silica by repeated oxidation and reduction cycles, and this effect contributed to promoting the castor oil hydrogenation activity.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.151-156
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• 2010

In this paper, we characterized bimetallic Pt-Ru/C alloy catalysts having four different compositions and compared the catalytic activities of the prepared alloys for CO oxidation. ICP-AES, EDS, XRD, TEM, and XAS were used to investigate the composition, degree of alloying, particle size, and electronic structure of the prepared Pt-Ru/C catalysts. Those results indicated the synthesis of the alloy catalysts with intended composition and uniform size. The electrochemical study of the characterized alloys showed higher catalytic activity for CO oxidation than that of the commercial Pt/C (E-TEK, Inc., 20 wt %) catalyst. Especially, it was shown that the alloy catalyst with Ru composition of 50 atomic % gave the highest catalytic activity for CO oxidation.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.580-584
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• 2010

As water becomes more scarce around the world the reuse of treated wastewater is being recenlty considered as indispensible trend we need to follow. Especially, industrial area consuming large amount of water has been encouraged to reuse the treated wastewater to secure sufficient water for the production of merchandise. In this study, a study of advanced oxidation process for treatment of industrial wastewater. The treatment performance of UV and ozoznation and five types advanced oxidation processes such as UV/AC, UV/Catalyst, $O_3$/Catalyst, UV/$O_3$/Catalyst was experimentally investigated for reuse of industrial wastewater. The removal efficiency of $COD_{Cr}$, color were relatively evaluated in each treatment unit simulated outflow water of wastewater treatment area. UV/$O_3$/Catalyst process showed the highest $COD_{Cr}$ remaval and color remaval among proposed oxidation process.

• New & Renewable Energy
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• v.4 no.2
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• pp.39-44
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• 2008

Partial oxidation of methane was carried out by ceria-promoted Ni-substituted hydrotalcite-derived catalysts ($Ce_xNi_3$-HTlc ; x=$0.3{\sim}1.2$) in a fixed-bed reactor. The Ce/Ni ratio of 0.3/3 in the catalyst showed the best catalytic activity but the Ce/Ni ratio became higher above 0.3/3, the catalyst became less active in short-term tests. No ceria promoted catalyst was started to decrease $CH_4$ conversion after 20 h but the Ce/Ni ratio 0.3/3 catalyst was kept its stability in long-term tests.

• Journal of Korean Society for Atmospheric Environment
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• v.1 no.1
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• pp.43-51
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• 1985

This study is concerned with the oxidation of carbon monoxide on platinum and platinum-palladium catalysts. Catalysts were made by the impregnation method and flow reactor was used in the catalytic reaction. As for the mixed gases, carbon monoxide concentration varied from 1 to 4% and that of oxygen from 1 to 4%. $N_2$ was used as carrier gas and GHSV varied from 24, 000 $h^{-1} to 60, h^{-1}$. The temperature range was from 200 to $600^\circ$C. It was also taken into consideration that the heat and mass transfer resistance of our catalysts was negligible in the study. Experimental results showed that platinum-palladium catalyst was about 1.5-3.9% superior to platinum catalyst in conversion yield. When we used platinum-palladium catalyst, we observed that carbon monoxide oxidation was found to be 1 st order with respect to carbon monoxide concentration. Activation energy of the catalyst was 23.5 kcal/mol.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.179-189
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• 1997

Among aftertreatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now studied actively. In this study, a transient one-dimensional model developed to simulate the thermal and conversion characteristics of adiabatic monolithic converters operating under warm up conditions is presented. This model takes into account the gas solid heat and mass transfer, axial heat conduction, chemical reactions and the related heat release. The model has been used to analyze the transient response of an axisymmetric catalytic converter during a warm-up as a function of catalyst design parameters and operation conditions in order to observe their effects on the lightoff behaviour. The experimental test was carried out 2400 cc light diesel engine with DOC.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.5
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• pp.411-417
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• 2002

The purpose of this study is to evaluate the emission reduction characteristics depending on the formation of the catalyst which influences the development of the diesel oxidation catalyst (DOC) suitable for small-sized diesel engines. We also attempted to suggest the feasibility of it as an after-treatment device. The reduction efficiency of DOC for CO and HC was proportional to the contents of precious metals, and the particulate matter (PM) has been reduced as much as 53∼59%. The reduction rate of soluble organic fraction (SOF) by DOC attachment revealed 100%. The composition of sulfate in PM increased from 3%, 7∼11% by installation of DOC. It is described that increase of sulfate contributed to the production of PM. This result also showed that the SOF and sulfate have trade-off relationship.

• Journal of ILASS-Korea
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• v.14 no.1
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• pp.15-19
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• 2009

This paper is to investigated the analysis of performance characteristics of diesel oxidation catalyst (DOC) for diesel vehicle with 2.5L piston displacement. The performance evaluation test of DOC applied to test diesel vehicle was carried out for four kinds of DOCs manufactured from different company. The testing DOCs were randomly selected from the retrofit vehicle and then standard test vehicle that was representative for the application group was equipped with DOC for the test. In this verification test, the reduction rate of particulate matter (P.M.) and the deviation of the performance of the DOC were examined through CVS-75 mode of the standard vehicle and SOF reduction rate of specific DOC was investigated. It was found that some DOCs failed to pass the criteria of the P.M. reduction rate because of the reason seen catalyst aging even if they were same devices. In the result of SOF analysis, the specific DOC showed more PM reduction than SOF of PM. reduction exceptionally.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.134-139
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• 2003

This study was carried out to investigate the aging and conversion characteristics of oxidation catalysts for a natural gas vehicle with lean-bum system. The conversion of $CH_4$ was observed over the various composition ratio of PMs(Precious metals) and washcoating methods. On the fresh catalysts, Pd affected on the activity of $CH_4$ at low temperature more than other PMs in Pd-only and Rh/Pd/Pt catalysts. The activity at low temperature increased as a mount of Pd increases. On the aged catalysts, the $CH_4$ conversion efficiency of Pd-only catalyst with mono-layer washcoat decreased more than that of the other catalysts of $CH_4$ conversion. It was observed that the thermal durability of Rh/Pd/Pt catalysts with double-layer washcoat was better than the single washcoat catalyst.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.489-494
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• 2006

Goethite, hematite, magnetite and synthesized iron oxide are used as catalysts for Fenton-type oxidation of phenol. The synthesized iron oxides were characterized by X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The catalytic activity of these materials is classified according to the observed rate of phenol oxidation. The effectiveness of the catalysts followed the sequence: ferrous ion > synthesized iron oxide >> magnetite hematite > goethite. According to these results, the most effective iron oxide catalyst had the structure similar to natural hematite. The surface oxidation state of the catalyst was between magnetite and hematite (+2.5 ~ +3.0). Phenol degraded completely in 40 min at neutral pH (pH = 7). Soluble ferric and ferrous ions were not detected in the filtrate from Fenton reaction solution by AAS. The formation of hydroxyl radicals was confirmed by EPR.