• International Journal of Automotive Technology
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• 제2권2호
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• pp.77-83
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• 2001

Effect of ethene on the $DeNO_X$ conversion process in a simulated diesel engine operating conditions was investigated experimentally and theoretically. With the addition of even a small amount of ethene the NO to $NO_2$ conversion enhances greatly. The energy required to convert one NO molecule is 27 eV with 250 ppm ethene added, while 137 eV without ethene at 473 K. The effect of energy density, temperature, and the initial concentrations of ethene and oxygen are also discussed and the results show that the increase of the mentioned parameters lead to the promotion of NO oxidation. A kinetic model used in this study shows good agreement with the experimental result. Byproducts like formaldehyde ($CH_2$ 0) and methyl nitrite ($CH_3$ ONO) predicted by model calculation are broken up into CO and $H_2O$ eventually when high energy is delivered to the gas mixture. Sensitivity analysis shows that the main reactions of NO oxidation when ethene is added we: $HO_2+ NO \arrow NO_2 + OH, RO_2 + NO \arrow NO_2 + RO$, where R is a hydrocarbon radical. Also the direct oxidizing reaction of NO with O cannot be neglected.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.157-162
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• 2002

The characteristics of DeNOx conversion process by plasma/post-heating system with the simulated gas containing ethene is investigated experimentally. Without plasma treatment, $NO-NO_2$ conversion doesn't occur by $400^{\circ}C$ in a mixture of $N_2/O_2$ with a trace gas of ethene. But $NO-NO_2$ conversion occurs as temperature increases above $400^{\circ}C$. The NO can, however, be converted to $NO_2$ at lower temperatures by treating the gas mixture with non-thermal plasma. The $NO-NO_2$ conversion enhances further by passing the plasma treated gas through the post-heating furnace. Results show that 20%${\sim}50%$ more conversion of NO to $NO_2$ is observed when the temperatures of the post-heating furnace are maintained at $300^{\circ}C$ or $400^{\circ}C$. The additional $NO-NO_2$ conversion by post-heating is due to the reaction of ethene with the byproducts or radicals generated from the plasma reaction.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.185-185
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• 2007

20세기에 들어 산업, 군사 및 다양한 목적으로 비인화성 용매인 PCE와 TCE의 사용량이 증대하였다. 주의를 필요로 하는 물질임에도 불구하고 부주의한 사용과 보관으로 인해 토양, 퇴적토, 지하수에 심각하게 오염되었다. High-chlorinated ethenes은 호기성 박테리아의 oxygenation에 의해 분해되지 않는다. PEC및 TCE의 완전한 탈염소화는 혐기성조건에서만 관찰되어지며, 지난 10연년간의 연구에 의해서 탈염소화 혐기성 미생물의 수의 보고는 증가되었다. 혐기성 조건에서 탈염소화 미생물에 의해 PCE와 TCE는 less-chlorinated ethenes 또는 무해한 ethene으로 전환이 가능하다. 본 연구는 lactate를 electron donor로 이용해 PCE에서 ethene까지 완전히 탈염소화하는 혐기성 배양을 수행했다. PCE로 오염된 퇴적토 시료로부터 혐기성 미생물 배양을 성공했다. PCE가 ethene까지 완전히 분해되는 것이 관찰되었다. 추가적으로 혐기성 미생물 배양액에서 1,2-cis-dichloroethene (cis-DCE)와 vinyl chloride (VC)의 축적이 일어남을 관찰하였다. 혐기성 미생물 배양액에서 Dehalococcoides 16S rRNA gene sequences에 특이적으로 반응하는 primer를 이용한 DGGE를 통해 미생물 군집을 분석하였다. 결론적으로, 우리의 연구에서 PCE를 감소시키는 배양액을 배양했으며, 이 배양엑에는 Dehalococcoides sp. 존재하는 것을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.120-129
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• 2016

An industrial complex in Wonju, contaminated with trichloroethene (TCE), was one of the most problematic sites in Korea. Despite repeated remedial trials for decades, chlorinated ethenes remained as sources of down-gradient groundwater contamination. Recent efforts were being made to remove the contaminants of the area, but knowledge of the indigenous microbial communities and their dechlorination abilities were unknown. Thus, the objectives of the present study were (i) to evaluate the dechlorination abilities of indigenous microbes at the contaminated site, (ii) to characterize which microbes and reductive dehalogenase genes were responsible for the dechlorination reactions, and (iii) to develop a PCE-to-ethene dechlorinating microbial consortium. An enrichment culture that dechlorinates PCE to ethene was obtained from Wonju stream, nearby a trichloroethene (TCE)-contaminated industrial complex. The community profiling revealed that known organohalide-respiring microbes, such as Geobacter, Desulfuromonas, and Dehalococcoides grew during the incubation with chlorinated ethenes. Although Chloroflexi populations (i.e., Longilinea and Bellilinea) were the most enriched in the sediment microcosms, those were not found in the transfer cultures. Based upon the results from pyrosequencing of 16S rRNA gene amplicons and qPCR using TaqMan chemistry, close relatives of Dehalococcoides mccartyi strains FL2 and GT seemed to be dominant and responsible for the complete detoxification of chlorinated ethenes in the transfer cultures. This study also demonstrated that the contaminated site harbors indigenous microbes that can convert PCE to ethene, and the developed consortium can be an important resource for future bioremediation efforts.

• 대한화학회지
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• 제61권4호
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• pp.139-142
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• 2017

Ethene ($C_2H_4$), which is produced in plants as they mature, was used to study its photoacoustic properties using photoacoustic spectroscopy. Detection of trace amounts, with $N_2$ gas, of $C_2H_4$ gas was also applied. The gas was tested in various conditions-temperature, concentration of the gas, gas cell length, and power of the laser- to determine their effect on the photoacoustic signal, the ideal conditions to detect trace gas amounts, and concentration of $C_2H_4$ produced by an avocado and a banana. A detection limit of 10 ppm was determined for pure $C_2H_4$. A detection of 5% and 13% (by volume) concentration of $C_2H_4$ was produced for a ripening avocado and banana, respectively, in closed space.

• Bulletin of the Korean Chemical Society
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• 제23권9호
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• pp.1309-1338
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• 2002

The fluorescence and photoisomerization quantum yields of trans-1-(9-anthryl)-2-(4-pyridyl)ethene (t-4-APyE), 1-(10-methyl-9-anthryl)-2-(4-pyridyl)ethene (t-4-MeAPyE), and 1-(10-chloro-9-anthryl)-2-(4- pyridyl)ethene (t-4-ClAPyE) were measured in cyclohexane, acetonitrile, and methanol at room temperature.Polar solvents result in the drastic reduction of fluorescence quantum yield and increase of photoisomerization quantum yield for all three compounds. These results are probably due to the stabilization of intramolecular charge transfer (ICT) excited state in polar solvent. The higher contribution of ICT in the presence of more electron-donating methyl substituent, manifested by largest positive fluorescence solvatochromism, indicates that the pyridine ring acts as an electron acceptor. Protonation or methylation makes pyridine ring stronger electron acceptor and causes long-wavelength ground state charge transfer absorption band and complete quenching of fluorescence. The fluorescence from t-4-APyE derivatives can be switched off responding external stimuli viz. medium polarity, protonation, or methylation.

• Journal of Photoscience
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• 제6권2호
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• pp.67-70
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• 1999

trans-1-(9-Anthryl)-2-(n-pyridyl)ethene (t-n-APyE, n=2 or 4) and trans-1-(9-anthryl)-2-pyrazinylethene (T-APzE) exhibits solvent-dependent fluorescence and efficient trans)cis photoisomerization. Photochemical reactivities of t-2-APyE, t-4-APyE, and t-APzE have been investigated in nonpolar and polar solvents. In nonpolar solvent, parallel photocyclization reaction occurs very efficiently in competition with the fluorescence and photoisomerization. But, in polar solvent, photocyclization was not observed. It is probably due to the stabilization of charge separated state in polar solvent, which is an intermediate in photoisomerization reaction.

• 한국축산시설환경학회지
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• 제10권1호
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• pp.29-36
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• 2004

양돈폐수의 원수, 활성오니정화처리, 오존 처리 및 $TiO_2$처리 등 각 정화처리단계별 유기물질의 성분특성 및 분자량의 분포의 변화를 알아보기 위하여 시험을 수행하였으며 그 결과는 다음과 같다. 1. 양돈폐수 원수 중에는 acetic acid, 2-butanone, hexane, chloroform, propionic acid, butanoic acid 등 33종의 유기물질이 포함되어 있었으며 phenol 28.7%, benzoic acid 9.9%, benzeneacetic acid 13.3% 등으로 고른 분포를 보였다. 2. 오존처리 후 ethene, pentane, 2-methyl-propanal, hexane, furan 등 13종의 유기물질이 존재하였으며, hexane이 67.8%로 대부분을 차지하는 것으로 나타났다. 3. $TiO_2$ 처리를 한 후에는 ethene, hexane, chloroform, 1-decene, silane 등 12종의 유기물질이 존재하였으며, ethene 8.8%, hexane 16.2%, 1-dodecene 8.0%, 1-tetradecene 10.8%, cyclo-trisiloxane 12.6% 등의 분포를 보였다. 4. 양돈폐수 원수는 500Da 이하의 분자량이 15%, 500-1,000Da 분자량이 14% 1,000∼3,000Da 분자량인 물질은 21%를 차지하였다. 5. 활성오니처리 후 분자량 500Da 이하는 7%, 500∼1,000Da 12%, 1,000∼3,000Da 10%이었으며 난분해성 물질인 분자량 3,000∼10,000Da 24%, 10,000Da 이상 26%로 고분자 물질의 분포가 높아졌다. 6. $TiO_2$ 처리 후 분자량 3,000∼10,000Da 5%, 분자량 10,000Da 이상 5%로 급격히 감소한 반면 분자량 500Da 이하 31%, 분자량 500∼1,000Da 54%를 차지였다.

• Bulletin of the Korean Chemical Society
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• 제23권11호
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• pp.1685-1688
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• 2002

• Journal of Photoscience
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• 제6권2호
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• pp.61-65
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• 1999

The fluorescence properties and photoisomerization behavior of 1-(9-anthryl)-2-(n-quinolinyl)ethene (n-AQE, n=2-4) have been investigated in various solvents. t-3-AQE is strongly fluorescent, but does not accomplish photoisomerization, similar to parent hydrocarbon compound, t-1-(9-anthryl)-2-phenylethene (t-9-APE) or t-1-(9-anthryl)-2-(1-naphthyl)ethene (t-1-ANE). Fluorescence and photoisomerization oft-2-AQE and t-4-AQE are strongly affected by solvent polarity. Dependence of fluorescence quantum yield on the solvent polarity is moderate for t-2-AQE and large for t-4-AQE. In nonpolar solvent (in n-hexane), they exhibit relatively strong fluorescence, but do not isomerize to cis isomer on irradiation, even if inefficient isomerization is observed for t-4-AQE. However, as solvent polarity increases, their fluorescences become weak with efficient photoisomerization to corresponding cis isomer. Intramolecular charge-transfer excited state is presumed to contribute to photoisomerization. The S$_1$ decay parameters were found to be solvent-dependent due to the charge-transfer character of lowest S$_1$ state. In polar solvents, the activation barrier to twisting is reduced enhancing the isomerization of r-2-AQE and t-4-AQE in the singlet manifold.