• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.909-915
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• 2002

The biodegradation of BTEX components (benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene) individually and in mixtures was investigated using the o-xylene-degrading thermo-tolerant bacterium Ralsronia sp. strain PHS1 , which utilizes benzene, toluene, ethylbenzene, or o-xylene as its sole carbon source. The results showed that as a single substrate for growth, benzene was superior to both toluene and ethylbenzene. While growth inhibition was severe at higher o-xylene concentrations, no inhibition was observed (up to 100 mg $l^-1$) with ethylbenzene. In mixtures of BTEX compounds, the PHS1 culture was shown to degrade all six BTEX components and the degradation rates were in the order of benzene, toluene, o-xylene, ethylbenzene, and m- and p-xylene. m-Xylene and p-xylene were found to be co-metabolized by this microorganism in the presence of the growth-supporting BTEX compounds. In binary mixtures containing the growth substrates (benzene, toluene, ethylbenzene. and o-xylene), PHS1 degraded each BTEX compound faster when it was alone than when it was a component of a BTEX mixture, although the degree of inhibition varied according to the substrates in the mixtures. p-Xylene was shown to be the most potent inhibitor of BTEX biodegradation in binary mixtures. On the other hand, the degradation rates of the non-growth substrates (m-xylene and p-xylene) were significantly enhanced by the addition of growth substrates. The substrate utilization patterns between PHS1 and other microorganisms were also examined.

• 멤브레인
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• 제22권2호
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• pp.120-127
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• 2012

본 연구에서는 혼합 자일렌에서 에틸벤젠을 분리하기 위하여 제올라이트 분리막을 이용하였다. 마이크로웨이브 합성 온도에 변화를 주어 제조한 TS-1 제올라이트 결정을 알루미나 튜브에 성장시키기 위해 3-chloropropyltrimethoxysilane를 코팅 후 TS-1 nano seed를 안착시키고 마이크로웨이브 합성법을 이용한 2차 성장을 통해 3~4 ${\mu}m$의 두께를 가지는 얇은 TS-1 제올라이트 분리막을 제조하였다. 제조한 분리막을 이용하여 에틸벤젠/메타자일렌/파라자일렌이 혼합된 혼합 자일렌으로부터 에틸벤젠을 분리하였다. 마이크로웨이브 합성 온도가 증가할수록 제올라이트 결정의 크기가 비례하여 증가하였다. 또한 반응기의 온도가 $200^{\circ}C$에서 가장 높은 투과 플럭스와 선택도를 가졌다. 가장 좋은 에틸벤젠 분리 성능을 보인 분리막은 마이크로웨이브 합성 온도가 $170^{\circ}C$인 분리막이고 선택도 값은 2.64였다(에틸벤젠 투과 플럭스 : 1703.0 mol/$m^2{\cdot}s{\cdot}Pa$).

• 한국환경과학회지
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• 제22권2호
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• pp.163-171
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• 2013

The aggregate risk assessment on xylene and ethylbenzene was carried out according to the guidance established newly in 2010 with the purpose of providing information for risk management. In human exposure assessment, the results indicated that lower ages were exposed more and that, in the interior space at home, the highest level of human exposure occurred via inhalation. At outdoor spaces, exposures via inhalation and drinking were less than 1%. In human health risk characterization, xylene showed HI(Hazard Index) < 1 in all ages. When reasonable maximum exposure(RME) was applied, HI for young children was 0.64. The HI of ethylbenzene was also below 1(0.02~0.04) in all ages, indicating no potential risk. From this study, it is considered that xylene need to be continous monitoring with interest because this substance may be more sensitive on young age group. In additon, to reduce the uncertainty of the risk assessment, the korean exposure factors on young age group such as infant, children had to be established as soon as possible.

• Molecular & Cellular Toxicology
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• 제4권4호
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• pp.267-277
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• 2008

Benzene and ethylbenzene (BE), the volatile organic compounds (VOCs) are common constituents of cleaning and degreasing agents, paints, pesticides, personal care products, gasoline and solvents. VOCs are evaporated at room temperature and most of them exhibit acute and chronic toxicity to human. Chronic exposure of benzene is responsible for myeloid leukemia and also ethylbenzene is also recognized as a possible carcinogen. To evaluate the BE effect on human, whole human genome 35 K oligonucleotide microarray were screened for the identification of the differential expression profiling. We identified 280 up-regulated and 201 down-regulated genes changed by more than 1.5 fold by BE exposure. Functional analysis was carried out by using DAVID bioinformatics software. Clustering of these differentially expressed genes were associated with immune response, cytokine-cytokine receptor interaction, toll-like signaling pathway, small cell lung cancer, immune response, apoptosis, p53 signaling pathway and MAPKKK cascade possibly constituting alternative or subordinate pathways of hematotoxicity and immune toxicity. Gene ontology analysis methods including biological process, cellular components, molecular function and KEGG pathway thus provide a fundamental basis of the molecular pathways through BEs exposure in human lymphoma cells. This may provides a valuable information to do further analysis to explore the mechanism of BE induced hematotoxicity.

• 설비공학논문집
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• 제18권2호
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• pp.137-143
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• 2006

This study has been conducted to quantify the emissions of Volatile Organic Compounds (VOCs) in a conference room. The carpet has emitted a variety of VOCs, but in this study, 2 VOCs compounds have been considered: Ethylbenzene and 1, 2, 3-Trimethylbenzene. In this study, a three dimensional numerical analysis has been carried out to investigate the emission and behavior characteristics of Ethylbenzene and 1, 2, 3-Trimethylbenzene emitted from the carpet in the conference room. The mass diffusion coefficient and the initial concentrations of VOCs in the carpet have been obtained from experimental data with non-linear regression. It has been found that the concentrations and emission factors of VOCs have exponentially decayed with time and that the concentration gradients and emission factors of VOCs are different from each other for various components. This study may supply fundamental understandings for the emission and behavior characteristics of VOCs.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.374-377
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• 2000

본 연구에 사용한 Pseudomonas sp. BCNU 154는 Gram 음성 toluene 내성세균으로 형태적${\cdot}$생리적 특성을 비교하여 보았을 때 Pseudomonas 속임이 확인되었다. 폭넓은 유기용매에 대한 내성한계를 가지고 있으며 Pseudomonas sp. BCNU 154 toluene 내성균주는 Modified Luria-Bertani(LBM) 배지에서 잘 자랐으며, $30^{\circ}C$에서 최적의 생육상태를 나타내었다. 최적 pH는 6에서 7로 나타났으며 1%의 toluene을 첨가하였을 경우에는 pH 2에서 8에 이르는 넓은 pH대에서 잘 자랐으며, cumene은 pH 6에서 10까지의 범위에서 좋은 성장을 보였다. Pseudomonas sp. BCNU 154 균주의 toluene, ethylbenzene, ${\rho}$ -xylene, cumene분해는 $1g/{\ell}$의 농도로 첨가시 toluene의 경우 97%이상이 분해되었고, ${\rho}$은 92%, ethylbenzene은 80%이며, cumene은 90% 이상이 분해되는 것으로 나타났다. 따라서 각 유기용매에 대해 대체로 12시간 내에 90%이상의 분해가 이루어졌으며, ethylbenzene의 경우에는 성장곡선과 마찬가지로 일정시간이 지난 후 성장과 분해가 둔화되다가 다시 성장과 분해가 일어나는 현상을 보였다.

• 한국가스학회지
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• 제19권5호
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• pp.54-60
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• 2015

최소자연발화온도는 가연성물질이 주위의 열에 의해 스스로 발화하는 최저온도이다. 최소자연발화온도는 유기혼합물중 가연성 액체혼합물의 안전한 취급을 위해서 중요한 지표가 된다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 노말데칸과 에틸벤젠 계의 최소자연발화온도를 측정하였다. 이성분계를 구성하는 노말데칸과 에틸벤젠의 최소자연발화온도는 각 각 $210^{\circ}C$, $430^{\circ}C$로 측정되었다. 그리고 측정된 노말데칸과 에틸벤젠 혼합물의 최소자연발화온도는 제시된 식에 의한 예측값과 약 $11^{\circ}C$평균절대오차에서 일치하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.382-385
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• 2003

Organic solvent tolerant bacterium, designated as strain BCNU 106 is a gram negative, rod-shaped aerobe and grows on benzene, toluene, ethylbenzene, and xylenes (BTEX) as a sole carbon source. According to 16S rDNA analysis and fatty acid analysis, strain BCNU 106 showed highest similarity to Pseudomonas syringae var. savastanoi (Pseudomonas savastanoi). Strain BCNU 106 was able to utilize toluene, ethylbenzene, both o-, m-, p-xylene , m-cresol and o-cresol. The degradation of o-, m-, p-xylene by strain BCNU 106 is particularly important, since o-xylene is a compound of considerable environmental interest, owing to its recalcitrance; and very few microorganism have been reported to utilize both o-, m-, p-xylene as a sole carbon source.

• 환경위생공학
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• 제16권3호
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• pp.72-79
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• 2001

The selective catalytic oxidation of toxic aromatic solvents (benzene, toluene, ethylbenzene, and styrene) and their mixtures were studied on a $Pt/{\;}{\gamma}-Al_2O_3$ catalyst at temperature ranging from $160~350^{\circ}C$. The deep conversion of aromatic solvents was increased as the inlet concentration was decreased and the reaction temperature was increased. The reactivity increases in order benzene > toluene > ethylbenzene > styrene. In mixture, remarkable effects on reaction rate and selectivity have been evidence ; the strongest inhibition effect is shown by styrene and increase in a reverse order with respect to that of reactivity. The inhibition effect was increased in order styrene > ethylbenzene > toluzene > benzene. This trend is due to the competition adsorption between the two or three reactants on the oxidized catalyst. Also, the deep conversion change of benzene was a small in tertiary mixtures(including of benzene and styrene) comparing with conversion characteristics of binary mixture with styrene. This result was due to small concentration of styrene. which had very strong inhibition effect.

• Bulletin of the Korean Chemical Society
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• 제19권12호
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• pp.1342-1346
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• 1998

The dehydrogenation of ethylbenzene with carbon dioxide has been carried out over ZSM-5 zeolite-supported iron oxide catalyst as well as commercial catalyst (K-Fe2O3) and unsupported iron oxide (Fe3O4) for comparison. In the dehydrogenation over the ZSM-5 zeolite-supported iron oxide catalyst, ethylbenzene is predominantly converted to styrene by an oxidative pathway in the presence of excess carbon dioxide. Carbon dioxide in this reaction is found to play a role as an oxidant for promoting catalytic activity as well as coke resistance of catalyst. On the other hand, both of commercial catalyst and unsupported Fe2O4 exhibit considerable decrease in catalytic activity under the same condition. It is suggested that an active phase for the dehydrogenation with carbon dioxide over ZSM-5 zeolite-supported iron oxide catalyst would be rather a reduced and isolated magnetite (Fe3O4)-like phase having oxygen deficiency in the zeolite matrix.