• Title/Summary/Keyword: Gaseous volatile organic compounds

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

  • 이창수;이영화
    • Journal of Environmental Science International
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    • v.11 no.12
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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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    • v.36 no.6
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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.

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

  • 이창수
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.11a
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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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    • v.12 no.2
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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.

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

  • 나광삼;김용표
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.4
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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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    • v.16 no.1
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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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    • v.17 no.E3
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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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    • v.17 no.E2
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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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Analysis of Higher Temporal Moments for Breakthrough Curves of Volatile Organic Compounds in Unsaturated Soil (불포화 토양에서 유동하는 가스상 Volatile Organic Compounds의 출현곡선에 대한 고차 Temporal Moment의 분석)

  • Kim, Heon-Ki
    • Journal of Soil and Groundwater Environment
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    • v.12 no.6
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    • pp.60-69
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    • 2007
  • Understanding the behavior of gas phase VOCs (volatile organic compounds) in unsaturated soils is of a great environmental importance for public health concerns. Moment analysis for the breakthrough curves (BTCs) during transport of chemicals in porous media was known to be a useful tool to evaluate the velocity, spreadness, and the skewness of the plume of the chemicals. In this study, the temporal moments of the BTCs of a group of VOCs were analyzed for the gaseous transport in an unsaturated soil. BTCs were measured using lab-scale column experiments for four different VOCs at the water saturation range of 0.04-0.46, and for eleven VOCs at a water saturation of 0.21. The central second and third moments of the VOCs were compared with the water saturation and the first moment. It was found that both central second and third moments increased with the first moment. The central third moment was, however, found to be more sensitive to the first moment.

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

  • Kim, Jeong;Jang, Young-Kee;Choi, Sang-Jin;Kim, Jeong-Soo;Seo, Choong-Yeol;Son, Ji-Hwan
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.1
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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.