• Analytical Science and Technology
• /
• v.10 no.5
• /
• pp.332-342
• /
• 1997

Fifteen volatile organic pollutants were spiked in blank water at the concentration of $20{\mu}g/L$ and analyzed with Purge and Trap and GC/MS. As a result, the overall mean recovery of 100% was obtained with a mean relative standard deviation of 3.6%. The method detection limits were in the range of $1.9{\sim}3.3{\mu}g/L$. In the wastewater analysis of Banwol dyeing comlex, 15 organic compounds were identified and three of these were quantified. Among the compounds identified, only trichloroethylene and tetrachloroethylene are regulated in wastewater by the Korea Ministry of Environment. But, the concentration of these two compounds were below the government allowance level.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.6
• /
• pp.60-69
• /
• 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.

• KSBB Journal
• /
• v.16 no.3
• /
• pp.281-285
• /
• 2001

Biofiltration of volatile organic compounds (VOCs) was performed for 80 days in a biofilter packed with peat. The empty bed residence time was 3.2 min. for a gas mixture of isoprene, dimethyl sulfide, chloroform. benzene, trichlorethylene, toluene, m0xylene, o-xylene and styrene. After 34 days of acclimatization the removal efficiency for a 83 g/㎥ gas input was 93% at $25^{circ}C$ and 73% at $45^{circ}C$, respectively. The maximum cell density at $25^{circ}C$ was 1.12$\times$10(sup)8 cells/g. Removal efficiencies of m-xylene and toluene (91%) were better than that of benzene (86%). The first quarter of the packed column removed 60% of the incoming VOCs.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.05b
• /
• pp.217-218
• /
• 2003

오늘날 대기환경에 존재하는 여러 오염물질 중에서 오존의 생성과 밀접한 관련이 있는 질소산화물과 휘발성유기화합물 (volatile organic compound, VOC)의 대기 환경학적 역할의 중요성이 점차 부각되고 있다 (Liu et al., 2000. VOC는 비록 대기 중에 극미량 농도로 존재하지만, 이들 성분이 대기환경의 변화에 미치는 잠재적 영향력은 가늠하기 어려울 정도로 막대하다. 지금까지 도심환경에 대한 VOC 성분의 분포특성을 설명하기 위해, 주요 인위적 기원의 VOC 성분들의 주구성인자로 간주할 수 있는 benzene, toluene, ethyl benzene, xylene (일반적으로 이들을 총칭하여 BTEX라 한다)을 위시한 방향족 화합물의 핵심성분들에 대한 환경거동 및 단주기적 분포특성에 대한 관측이 많은 연구자들에 의해 수행되었다(eg., Keymeulen et al., 2001). (중략)

• Analytical Science and Technology
• /
• v.21 no.4
• /
• pp.296-303
• /
• 2008

This study was performed to establish an analytical method of PAHs in oil contaminated soil of these methods by evaluating the PAHs test methods from US EPA and ISO etc. The application to domestic contaminated soil leads to a conclusion that alumina column is a more effective clean-up procedure for oil contaminated soil rather than the others. It is proposed with the new analytical method of 12 PAHs except for more volatile compounds (naphthalene, acenaphthylene, acenaphthene, fluorene). The recovery of PAHs in this method ranged 67~107%. The oil contaminated soil samples were analyzed using GC/MSD. The concentration of PAHs ranged $78.68{\sim}275.57{\mu}g/kg$. The predominated compounds were fluoranthene, pyrene and chrysene attributing about 70% of total concentration. The level of Benzo[a]pyrene ranged $1.76{\sim}24.65{\mu}g/kg$.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.47 no.3
• /
• pp.185-191
• /
• 2021

Environmental pollution is defined as contamination of the earth's environment with materials which interfere with human health, quality of life, or the natural functioning of the ecosystem. Whenever a prolonged and repetitive exposure to environmental stressors exceeds the skin's normal defensive potential, there is a disturbance in the skin barrier function leading to the development of various skin diseases. Major air pollutants which affect the skin are polycyclic aromatic hydrocarbons, volatile organic compounds, nitrogen oxides, particulate matter, cigarette smoke, heavy metals and arsenic. Dermal uptake depends on the deposition of air pollutants on the skin surface, the composition of epidermal lipids, and the diffusion through the epidermis to the blood vessels.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.05b
• /
• pp.401-402
• /
• 2003

TiO$_2$는 광촉매로서 자외선이 조사되면 여기상태로 되어 광활성을 나타내므로, 휘발성 유기화합물(VOCs), 악취, 중금속 물질 등을 제어하는데 널리 사용되고 있다(Lee and Biswas, 1998). TiO$_2$는 기상 및 액상 등 여러 가지 방법으로 제조되고 있는데(Morooka et al., 1989), 본 연구에서는 기상 방법의 하나인 전기가열 튜브로를 이용하여 TiOs 입자를 제조하였다. 즉, TTIP(titanium isopropoxide, Ti[OCH($CH_3$)$_2$]$_4$)와 공기를 전기가열 튜브로의 d열원을 이용하여 반응시키는 방법을 사용하였다. TiO2의 광활성에 영향을 미치는 변수로는 전기로의 온도, TTIP의 초기 농도, carrier gas의 유량, 산화시키기 위한 산소의 양, 수분의 양 등이 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.04a
• /
• pp.195-196
• /
• 2002

휘발성 유기화합물(Volatile Organic Compounds; VOCs)은 용제를 사용하는 도장공정, 석유화학공정 등 각종 산업공정과 자동차로부터 배출되어 대기중에 광화학 산화물을 형성하거나 그 자체로 발암성 또는 악취성을 나타내는 물질로 인체에 유해한 영향을 미치며, 한편 간접적으로 온실가스의 역할을 하는 것으로 알려졌다. 가속기를 이용한 전자빔 처리공정의 경우 상온에서 운영되고 2차오염물 발생이 거의 없으며, 특히 유량이 매우 크고 저농도로 배출되는 VOCs의 처리의 경우에 기존의 처리법 보다 더욱 경제적이고 효율적으로 적용될수 있다. (중략)

• Journal of the Korean Applied Science and Technology
• /
• v.29 no.2
• /
• pp.199-204
• /
• 2012

Organic thin-film transistors (OTFTs) have received considerable attention because their potential applications for nano-scale thin-film structures have been widely researched for large-scale integration industries, such as semiconductors and displays. However, research in developing n-type materials and devices has been relatively shortage than developing p-type materials. Therefore, we report on the fabrication of top-contact [6,6]-phenyl-C61-butyricacidmethylester (PCBM) TFTs by using three different solvent, o-dichlorobenzene, toluene and chloroform. An appropriate choice of solvent shows that the electrical characteristics of PCBM TFTs can be improved. Moreover, our PCBM TFTs with the cross-linked Poly(4-vinylphenol) dielectric layer exhibits the most pronounced improvements in terms of the field-effect mobility (${\sim}0.034cm^2/Vs$) and the on/off current ratio (${\sim}1.3{\times}10^5$) for our results. From these results, it can be concluded that solvent-modification of an organic semiconductor in PCBM TFTs is useful and can be extended to further investigations on the PCBM TFTs having polymeric gate dielectrics. It is expected that process optimizations using solution-processing of organic semiconductor materials will allow the development of the n-type organic TFTs for low-cost electronics and various electronic applications.

• Applied Chemistry for Engineering
• /
• v.19 no.5
• /
• pp.574-581
• /
• 2008

The optimum regeneration conditions for the regeneration of three way spent catalysts (TWCs), which were taken from automobiles with different driving conditions, were investigated to evaluate the suitability as alternative catalysts for removing VOCs. The spent catalysts were washed with five different acids ($HNO_3$, $H_2SO_4$, $C_2H_2O_4$, $C_6H_8O_7$, and $H_3PO_4$) to remove contaminants and examine the optimum conditions for recovering the catalytic activity. The physicochemical properties of spent and its regenerated TWCs were evaluated by using nitrogen adsorption-desorption isotherms, XRD, and ICP. The relative atomic ratios of contaminants and platinum group metals (PGMs) of the spent TWCs were greatly dependent on the placed positions. The main contaminants formed were lubricant oil additives and metallic components. Also, the regeneration treatment increased the PGMs ratio, BET surface area, and average pore diameter of TWCs. The catalytic activity results indicated that the spent TWCs have the possibility for removing VOCs. Moreover, the employed acid treatments greatly enhanced the catalytic activity of the spent TWCs. Especially, nitric and oxalic acids provided the most improvement in the catalytic behavior. The catalytic activities of the regenerated TWCs were significantly influenced by the containing platinum ratios rather than the removal ratios of contaminants and the changes in the structural properties offered by the acid treatments.