• 제목/요약/키워드: Gaseous volatile organic compounds

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밀도차에 의해 발생하는 이송을 고려한 휘발성 유기화합물 가스의 거동 (Behavior of Gaseous Volatile Organic Compounds Considered by Density-Dependent Gas Advection)

  • 이창수;이영화
    • 한국환경과학회지
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    • 제11권12호
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    • pp.1321-1326
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    • 2002
  • A numerical model is investigated to predict a behavior of the gaseous volatile organic compounds and a subsurface contamination caused by them in the unsaturated zone. Two dimensional advective-dispersion equation caused by a density difference and two dimensional diffusion equation are computed by a finite difference method in the numerical model. A laboratory experiment is also carried out to compare the results of the numerical model. The dimensions of the experimental plume are 1.2m in length, 0.5m in height, and 0.05m in thickness. In comparing the result of 2 methods used in the numerical model with the one of the experiment respectively, the one of the advective-dispersion equation shows better than the one the diffusion equation.

Surface-enhanced infrared detection of benzene in air using a porous metal-organic-frameworks film

  • Kim, Raekyung;Jee, Seohyeon;Ryu, Unjin;Lee, Hyeon Shin;Kim, Se Yun;Choi, Kyung Min
    • Korean Journal of Chemical Engineering
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    • 제36권6호
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    • pp.975-980
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    • 2019
  • Infrared (IR) spectroscopy is a powerful technique for observing organic molecules, as it combines sensitive vibrational excitations with a non-destructive probe. However, gaseous volatile compounds in the air are challenging to detect, as they are not easy to immobilize in a sensing device and give enough signal by themselves. In this study, we fabricated a thin nanocrystalline metal-organic framework (nMOF) film on a surface plasmon resonance (SPR) substrate to enhance the IR vibration signal of the gaseous volatile compounds captured within the nMOF pores. Specifically, we synthesized nanocrystalline HKUST-1 (nHKUST-1) particles of ca. 80 nm diameter and used a colloidal dispersion of these particles to fabricate nHKUST-1 films by a spin-coating process. After finding that benzene was readily adsorbed onto nHKUST-1, an nHKUST-1 film deposited on a plasmonic Au substrate was successfully applied to the IR detection of gaseous benzene in air using surface-enhanced IR spectroscopy.

오염지하수 TCE 농도와 휘발계수와의 관계 (A Correlation Concentration of Contaminated Groundwater with Volatilization Coefficient)

  • 이창수
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2000년도 추계학술대회
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    • pp.266-269
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    • 2000
  • To understand the gaseous behaviour of volatile organic compounds in the unsaturated zone, their volatilization coefficient k$_{Lg}$ is evaluated. An experiment is conducted to examine the dependence of k$_{Lg}$ on the concentration of the dissolution, presence of unsaturated zone and depth of the unsaturated zone. The results show that the volatilization coefficient is not dependent on the concentration under the constant temperature and pressure. It is also find that k$_{Lg}$ depends on the presence of the unsaturated zone rather than its depth.depth.

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ULTRA-FINE PARTICLES AND GASEOUS VOLATILE ORGANIC COMPOUND EXPOSURES FROM THE REACTION OF OZONE AND CAR-AIR FRESHENER DURING METROPOLIS TRAVEL

  • Lamorena, Rheo B.;Park, Su-Mi;Bae, Gwi-Nam;Lee, Woo-Jin
    • Environmental Engineering Research
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    • 제12권2호
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    • pp.72-80
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    • 2007
  • Experiments were conducted to identify the emissions from the car air freshener and to identify the formation of ultra-fine particles and secondary gaseous compounds during the ozone-initiated oxidations with emitted VOCs. The identified primary constituents emitted from the car air freshener in this study were $\alpha$-pinene, $\beta$-pinene, $\rho$-cymene and limonene. Formation of ultra-fine particles (4.4-160 nm) was observed when ozone was injected into the chamber containing emitted monoterpenes from the air freshener. Particle number concentrations, particle mass concentrations, and surface concentrations were measured in time dependent experiments to describe the particle formation and growth within the chamber. The irritating secondary gaseous products formed during the ozone-initiated reactions include formaldehyde, acetaldehyde, acrolein, acetone, and propionaldehyde. Ozone concentration (50 and 100 ppb) and temperature (30 and $40^{\circ}C$) significantly affect the formation of particles and gaseous products during the ozone-initiated reactions. The results obtained in this study provided an insight on the potential exposure of particles and irritating secondary products formed during the ozone-initiated reaction to passengers in confined spaces.

울산 대기 중의 입자상, 기체상 물질의 수용성 이온 성분과 휘발성 유기화합물의 농도 (Concentrations of Water-soluble Particulate, Gaseous tons and Volatile Organic Compounds in the Ambient Air of Ulsan)

  • 나광삼;김용표
    • 한국대기환경학회지
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    • 제14권4호
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    • pp.281-292
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    • 1998
  • Ambient concentrations of gaseous, particulate phase ionic species, and VOCs (volatile organic compounds) were measured at two monitoring sites in the City of Ulsan during August 1997: one in industrial area and the other in downtown area. At each site, a three- stage filter pack sampler was used to collect fine particles and gaseous species, and air for VOC analysis was collected in stainless steel canisters. Concentrations of the ionic species at both sites were similar to each other. The VOC concentrations at the industrial site were approximately twice higher than those at the downtown site. This might be mainly due to the release of VOCs from the petrochemical industries. Daily variations of VOC concentrations at the industrial site were higher than that at the downtown site. This might be explained by the fact that emissions from industries were more irregular than those in downtown. The VOC concentrations in downtown were affected by both the local emissions and the emission from the petrochemical industries. The concentrations of selected hazardous organic components (HAPs) at the industrial site were similar to those of Yocheon industrial area but slightly higher than other cites and industrial areas, while those at the downtown site were comparable to those in other urban areas.

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VOC Emissions from Automotive Painting and Their Control: A Review

  • Kim, Byung-R.
    • Environmental Engineering Research
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    • 제16권1호
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    • pp.1-9
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    • 2011
  • During automotive painting, volatile organic compounds (VOCs) associated with the paint solvents are emitted to the atmosphere. Most VOC emissions come from spraying operations via the use of solvent-based paints, as the spraybooth air picks up gaseous solvent compounds and overspray paint materials. The VOCs consist of aromatic and aliphatic hydrocarbons, ketones, esters, alcohols, and glycolethers. Most VOCs (some hydrophilic VOCs are captured and retained in the water.) are captured by an adsorption system and thermally oxidized. In this paper, the processes involved in automotive painting and in VOC control are reviewed. The topics include: painting operations (briefly), the nature of VOCs, VOC-control processes (adsorption, absorption, biological removal, and thermal oxidation) and energy recovery from VOCs using a fuel reformer and a fuel cell, and the beneficial use of paint sludge.

A Kinetic Study on the Photocatalytic Degradation of Gas-Phase VOCs Using TiO$_2$ photocatalyst

  • Kim, Sang-Bum;Jo, Young-Min;Hong, Sung-Chang
    • Journal of Korean Society for Atmospheric Environment
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    • 제17권E3호
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    • pp.117-124
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    • 2001
  • The present paper examined the kinetics of photocatalytic degradation of volatile organic compounds (VOCs) including gaseous trichloroethylene (TCE) and acetone. In this study, we examined the effects of the initial concentration of VOCs and the light intensity of ultra-violet (UV). A batch photo-reactor was specifically designed for this work. The photocatalytic degradation rate increased with the initial concentration of VOCs but remained almost constant beyond a certain concentration. It matched well with the Langmuir-Hinshelwood (L-H) kinetic model. When the effect of light intensity was concerned, it was found that photocatalytic degradation occurs in two regimes with respect to light intensity.

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Effects of Water Vapor, Molecular Oxygen and Temperature on the Photocatalytic Degradation of Gas-Phase VOCs using $TiO_2$Photocatalyst: TCE and Acetone

  • Kim, Sang-Bum;Jo, Young-Min;Cha, Wang-Seong
    • Journal of Korean Society for Atmospheric Environment
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    • 제17권E2호
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    • pp.35-42
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    • 2001
  • Recent development of photocatalytic degradation method that is mediated by TiO$_2$ is of interest in the treatment of volatile organic compounds(VOCs). In this study, trichloroethylene(TCE) and acetone were closely examined in a batch scale of photo-reactor as a function of water vapor, oxygen, and temperature. Water vapor inhibited the photocatalytic degradation of acetone, while there was an optimum concentration in TCE. A lower efficiency was found in nitrogen atmosphere than air, and the effect of oxygen on photocatalytic degradation of acetone was greater than on that of TCE. The optimum reaction temperature on photocatalytic degradation was about 45$^{\circ}C$ for both compounds. NO organic byproducts were detected for both compounds under the present experimental conditions. It was ascertained that the photocatalytic reaction in a batch scale of photo-reactor was very effective in removing VOCs such as TCE and acetone in the gaseous phase.

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불포화 토양에서 유동하는 가스상 Volatile Organic Compounds의 출현곡선에 대한 고차 Temporal Moment의 분석 (Analysis of Higher Temporal Moments for Breakthrough Curves of Volatile Organic Compounds in Unsaturated Soil)

  • 김헌기
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제12권6호
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    • pp.60-69
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    • 2007
  • 토양에서 휘발성 유기화합물(VOC, volatile organic compound)의 유동특성을 이해하는 것은 오염물질의 확산을 예측하고 오염의 정도를 평가하며 대책을 수립하는 데 있어서 매우 중요하다. 토양과 같은 다공성매질에서 유동하는 물질의 출현곡선에 대한 모멘트의 분석을 통하여 화학물질의 유동속도, 플룸의 폭 및 비대칭정도를 평가할 수 있다. 본 연구에서는 실험실 규모의 토양 컬럼실험을 사용하여 VOC의 가스상 유동실험을 실시하였으며, 모두 네 가지의 VOC에 대하여 포화도(water saturation)범위 0.04-0.46에서 출현곡선을 측정하였다. 또한 포화도 0.21에서 열한가지의 VOC에 대하여 출현곡선을 측정하였다. 측정된 출현곡선의 중심 2차(central second)및 중심 3차(central third)모멘트는 포화도와 1차 모멘트(또는 지체상수)와 비교 분석되었다. VOC 출현곡선의 모멘트분석 결과 2차 및 3차 모멘트는 1차 모멘트의 2.23제곱 및 3.16제곱 함수로서 증가하였으며, 3차 모멘트가 2차 모멘트에 대하여 보다 민감하게 반응하였다. 이는 VOC가 토양가스상에서 이동할 때, 지체상수에 비례하여 가스 플룸의 폭과 비대칭성이 증가한다는 사실을 나타낸다.

자동차에서 배출되는 가스상 유해대기오염물질 (HAPs) 배출량 추정 (Estimation of Gaseous Hazardous Air Pollutants Emission from Vehicles)

  • 김정;장영기;최상진;김정수;서충열;손지환
    • 한국대기환경학회지
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    • 제29권1호
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    • pp.1-9
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    • 2013
  • Hazardous Air Pollutants (HAPs) are difficult to measure, analyze and assess for risk because of low ambient concentrations and varieties. Types of HAPs are Volatile organic compounds (VOCs), Polycyclic aromatic hydrocarbon (PAHs) and Aldehydes. HAP emissions from vehicles are a contributor to serious adverse health effects in urban areas. In this study, hazardous air pollutant emissions from road transport vehicles by Non-methane volatile organic compounds (NMVOC) weight fraction and PAHs emission factors are estimated in 2008. The top-five-most hazardous air pollutant emissions were estimated to toluene 864.3 ton/yr, acrolein 690.6 ton/yr, acetaldehyde 554.5 ton/yr, formaldehyde 498.7 ton/yr, propionaldehyde 421.6 ton/yr in 2008. The results for a cancer and non-cancer risk assessment of HAPs emissions show that the major cancer driver is formaldehyde and the non-cancer driver is acrolein.