• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1525-1528
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• 2005

The synthesis and characterization of ${K_3[Ru(C_2O_4)3]{\cdot}4H_2O\;(C_2O_4}^{2-}$ = oxalato anoin) complex are described, and its redox properties (in buffer solution of pH = 12) have been investigated. This complex is used for in situ generation of oxoruthenates complexes which have been characterized by electronic spectroscopy. Reaction of ${K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${S_2O_8}^{2-}$ in molar KOH generates trans-${[RuO_3(OH)_2]^{2-}/S_2O_8}^{2-}$ reagent while with excess ${BrO_3}^-$ in molar $Na_2CO_3$ generates ${[RuO_4]^-/BrO_3}^-$ reagent. Avoiding the direct use of [$RuO_4$] the organic-soluble $(n-Pr_4N)^+[RuO_4]^-$, (TPAP) has been isolated by reaction of $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${BrO_3}^-$ in molar carbonate and n-$Pr_4$NOH. In a mixture of $H_2O/CCl_4$ ruthenium tetraoxide can be generated by reaction of $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${IO_4}^-$. The catalytic activities of oxoruthenates that have been made from $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ towards the oxidation of benzyl alcohol, piperonyl alcohol, benzaldehyde and benzyl amine at room temperature have been studied.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.109-117
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• 2010

In the present study, the degradation characteristics of Lindane by Advanced Oxidation Processes(UV/$H_2O_2$, Photo-Fenton process) were studied. The degradation efficiency of Lindane in aqueous solution was investigated at various initial pH values, Fenton's reagent concentrations and initial concentrations of Lindane. GC-ECD was used to analyze lindane. Lindane has not been degraded without application of AOPs over two hours. But, approximately 5% of lindane was degraded with UV or $H_2O_2$ alone. Lindane with UV/$H_2O_2$ process showed approximately 7% higher removal efficiency than $H_2O_2$ process. In the UV/$H_2O_2$ process, the pH values did not affect the removal efficiency. The optimal mole ratio of $H_2O_2/Fe^{2+}$ for lindane degradation is about 1.0 in Photo-Fenton process. Also, the experimental results showed that lindane removal efficiency increased with the decrease of initial concentration of lindane. Under the same conditions, the order lindane of removal efficiency is as following : Photo-Fenton process > UV/$H_2O_2$ process > $H_2O_2$ process. In addition, intermediate products were identified by GC-MS techniques. Than PCCH(Pentachlorocyclohexene) was identified as a reaction intermediate of the Photo-Fenton process.

• Toxicological Research
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• v.18 no.4
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• pp.363-367
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• 2002

Reactive of gen species (ROS) contribute to several cellular function and are involved in the regulation of signal transduction, gene expression, and proliferation. In the present study, we investigated the effect of $H_2O_2$ treatment on IgM secretion in LPS-stimulated murine B Iymphoma, CH12.LX. Cells were treated directly With $H_2O_2$ and stimulated with LPS. $H_2O_2$ treatment during 72 h time period inhibited IgM secretion in LPS-stimulated CH12.LX cells in a dose- and time-dependent manners. After treatment with 50 $\mu\textrm{M}$ $H_2O_2$ during 72 h time period, the level of IgM in LPS-stimulated CH12.LX cells was markedly decreased, whereas cell viability was not significantly changed. Addition of $H_2O_2$ concomitantly with LPS, or 12 h post-LPS stimulation, produced a significant inhibition of IgM secretion, Whereas inhibitory effect of $H_2O_2$ on IgM secretion was not observed when added 24 h after LPS stimulation. These findings suggest that $H_2O_2$ can inhibit the secretion of IgM in LPS-stimulated CH15.LX cells, and may alter the events necessary for terminal B cell differentiation.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.4
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• pp.64-72
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• 1996

The effect of $O_3$, $O_3/pH$, and $O_3/H_2O_2$, $O_3/UV$, and $H_2O_2/UV$ advanced oxidation process(AOP) were investigated for the treatment of tetrachloroethylen(PCE) at various condition. The removal efficiency of 10, 20, and 30ppm PCE by ozonation were almost same, only about 60%. And pseudo first-order rate constants, ko for overall oxidation was about 0.097($min^{-1}$). In the $O_3/pH$ AOP experiment for the 20ppm PCE, the removal rate of PCE increased with the increase of pH. However, mineralization rate of PCE at pH 7 was higher than at pH 10. In the $O_3/H_2O_2$ AOP, the removal rate of PCE was the highest at peroxide-to-ozone dosage ratio of about 0.9, which PCE was removed over 99.95%. Despite 42% of PCE was directly photolyzed by the UV irradiation, the removal efficiency of PCE by $O_3/UV$ AOP was only about 70%. In $H_2O_2/UV$ AOP, the removal efficiency of PCE increased to about 98% in proportion to the $H_2O_2$ injection concentration at constant UV intensity of 5W/l.

• Korean Journal of Materials Research
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• v.22 no.5
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• pp.253-258
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• 2012

Activated magnetite ($Fe_3O_{4-{\delta}}$) was applied to reducing $CO_2$ gas emissions to avoid greenhouse effects. Wet and dry methods were developed as a $CO_2$ removal process. One of the typical dry methods is $CO_2$ decomposition using activated magnetite ($Fe_3O_{4-{\delta}}$). Generally, $Fe_3O_{4-{\delta}}$ is manufactured by reduction of $Fe_3O_4$ by $H_2$ gas. This process has an explosion risk. Therefore, a non-explosive process to make $Fe_3O_{4-{\delta}}$ was studied using $FeC_2O_4{\cdot}2H_2O$ and $N_2$. $FeSO_4{\cdot}7H_2O$ and $(NH_4)_2C_2O_4{\cdot}H_2O$ were used as starting materials. So, ${\alpha}-FeC_2O_4{\cdot}2H_2O$ was synthesized by precipitation method. During the calcination process, $FeC_2O_4{\cdot}2H_2O$ was decomposed to $Fe_3O_4$, CO, and $CO_2$. The specific surface area of the activated magnetite varied with the calcination temperature from 15.43 $m^2/g$ to 9.32 $m^2/g$. The densities of $FeC_2O_4{\cdot}2H_2O$ and $Fe_3O_4$ were 2.28 g/$cm^3$ and 5.2 g/$cm^3$, respectively. Also, the $Fe_3O_4$ was reduced to $Fe_3O_{4-{\delta}}$ by CO. From the TGA results in air of the specimen that was calcined at $450^{\circ}C$ for three hours in $N_2$ atmosphere, the ${\delta}$-value of $Fe_3O_{4-{\delta}}$ was estimated. The ${\delta}$-value of $Fe_3O_{4-{\delta}}$ was 0.3170 when the sample was heat treated at $400^{\circ}C$ for 3 hours and 0.6583 when the sample was heat treated at $450^{\circ}C$ for 3 hours. $Fe_3O_{4-{\delta}}$ was oxidized to $Fe_3O_4$ when $Fe_3O_{4-{\delta}}$ was reacted with $CO_2$ because $CO_2$ is decomposed to C and $O_2$.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.885-888
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• 1999

This study was carried out to determine the reaction kinetic constant of the dehydration - thermal decomposition of $Na_2B_4O_7{\cdot}10H_2O/Na_2B_4O_7{\cdot}5H_2O$ and to investigate the durability during the repeated use of a chemical heat-storage material and the reproducibility of reaction system. The order of the dehydration reaction was 1st-order. The reaction rate was directly proportional to a partial pressure difference of water steam. The kinetic constant was 0.27 and the reproducibility of dehydration reaction for a kinetic constant and a reaction order was excellent. The activity variation in the durability test of a chemical heat-storage material was within range of ${\pm}5%$ during the repeatedly use in several times.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1029-1033
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• 1997

Fundamental research of non-isothermic analysis of reaction rate has been carried out for the heat storage system using the thermal decomposition of $Na_2B_4O_7{\cdot}10H_2O$. It was found that the equilibrium temperature of the thermal decomposition reaction was lowered less than 373K in $Na_2B_4O_7{\cdot}10H_2O/Na_2B_4O_7{\cdot}5H_2O$ system, but the heat efficiency was unchanged. The initiation temperature of the reaction was varied from low to high temperature region with heating rate. The reaction order of the dehydration reaction by the thermal decomposition was appeared to be 0.67 by non-isothermic analysis, thereby $Na_2B_4O_7{\cdot}10H_2O$ may be used as a hemical heatstorage material.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.419-424
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• 2022

The oxidative degradation performance of the Erionyl Navy R dye was studied in this article. The investigation mainly focused on a comparative study between chemical oxidations by sodium hypochlorite (NaClO) and hydrogen peroxide (H₂O₂), and catalytic oxidations including the Fenton (Fe²⁺-H₂O₂) and Fenton-Like (Fe²⁺/ Fe³⁺/Co²⁺/ Mn²⁺-H₂O₂) or modified Fenton-like (Fe²⁺/ Fe³⁺ -NaClO) reactions. A discoloration and degradation of the Erionyl Navy R occurred after 30 minutes, which varies according to the oxidation system involved; 31%, 54%, <20%, 95%, and >96% losses were observed for Co²⁺-H₂O₂, Mn²⁺-H₂O₂, Fe²⁺-NaClO, Fe³⁺-NaClO), and Fe²⁺-H₂O₂ and Fe³⁺-H₂O₂, respectively.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.364-372
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• 1988

The mechanical properties and microstructure of ceramics of the system Al2O3-ZrO2-Y2O3 sintered at 1$650^{\circ}C$ for 2h after powder preparation by the precipitation method from Al2(SO4)3.18H2O, ZrOCl2.8H2O and YCl3.6H2O were investigated. The Al2O3-ZrO2-Y2O3 ceramics sintered at 1$650^{\circ}C$ for 2h after mixing alpha-Al2O3 and ZrO2-Y2O3 powders, both were separately precipitated and calcined, were found to have the relative density higher than 97.5% so that the strengthening and toughening mechanisms could be explained mainly as the stress-induced phase transformation. On the other hand, the sintered bodies prepared by co-precipitating the three starting materials were measured to have the relative density lower than 85% so that the degradation of strength were observed above 15 vol% ZrO2 contents due to the high porosity by which the effect of stress-induced phase transformation was assumed to be depressed.

• Industry Promotion Research
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• v.3 no.2
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• pp.1-8
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• 2018

In this study, the reaction mechanism of ethane and the reaction rate equation suitable for hydrocarbon reforming were studied. Through the reaction mechanism analysis, it was confirmed that three reactions (CO2 + H2, C2H6 + H2, C2H6 + H2O) proceed during the reforming reaction of ethane, each reaction rate (CO2+H2($r=3.42{\times}10-5molgcat.-1\;s-1$), C2H6+H2($r=3.18{\times}10-5mol\;gcat.-1s-1$), C2H6+H2O($r=1.84{\times}10-5mol\;gcat.-1s-1$)) was determined. It was confirmed that the C2H6 + H2O reaction was a rate determining step (RDS). And the reaction equation of this reaction can be expressed as r = kS * (KAKBPC2H6PH2O) / (1 + KAPC2H6 + KBPH2O) (KA = 2.052, KB = 6.384, $kS=0.189{\times}10-2$) through the Langmuir-Hinshelwood model. The obtained equation was compared with the derived power rate law without regard to the reaction mechanism and the power rate law was relatively similar fitting in the narrow concentration change region (about 2.5-4% of ethane, about 60-75% of water) It was confirmed that the LH model reaction equation based on the reaction mechanism shows a similar value to the experimental value in the wide concentration change region.