• Carbon letters
• /
• 제8권3호
• /
• pp.225-231
• /
• 2007

• 한국대기환경학회지
• /
• 제33권3호
• /
• pp.265-276
• /
• 2017

The $PM_{2.5}$ samples were obtained from coal combustion with the four different combustion temperatures (550, 700, 900 and $1100^{\circ}C$) to understand chemical composition in carbonaceous aerosol. OC concentration was the highest when the combustion temperature was $550^{\circ}C$, while, the highest concentration for EC was shown at $700^{\circ}C$ of the coal combustion temperature. However, OC concentrations were very low and EC was not detected when the temperature was over $900^{\circ}C$. It indicates complete combustion was achieved when the combustion temperature was over $900^{\circ}C$. For six groups of organic compounds, n-alkanes and n-alkanoic acids were predominant at all of the combustion temperature in smoke of coal combustion, while, PAHs was only detected at $550^{\circ}C$. The diagnostic ratios of PAHs calculated in this study were 0.59 for Fluoranthene/(Fluoranthene+Pyrene), reflecting the characteristics of coal combustion. The Carbon number Preference Index (CPI) values of n-alkanes which ranged from 0.9 to 1.3 also showed the characteristics of coal combustion.

• 한국대기환경학회지
• /
• 제31권4호
• /
• pp.345-355
• /
• 2015

Carbonaceous compounds in the atmospheric particulate matter with an aerodynamic diameter of less than or equal to a nominal $10{\mu}m$ ($PM_{10}$) were analyzed for the samples collected during the period of August 2006 to August 2007 at Jongro in Seoul. A total 18 dicarboxylic acids (DCAs) and levoglucosan, as well as organic carbon (OC), elemental carbon (EC), and water soluble organic carbon (WSOC), were analyzed. Distinctive seasonal patterns of the concentrations of OC, EC, and WSOC including levoglucosan were observed with the highest concentrations in winter and the lowest concentrations in summer. In addition, OC, WSOC, and most of DCAs showed also higher concentration in summer than in winter. Using the seasonal patterns and relevant indicative ratios (WSOC/EC and $OC_{sec}/OC_{tot}$) of the carbonaceous compounds, it was verified that (1) primary emission sources were elevated in winter, and (2) the formation of secondary OC increased due to the prompted photochemical reaction in summer. Results from this study also suggest that some organic compounds were likely attributed to longrange transport.

• Asian Journal of Atmospheric Environment
• /
• 제7권3호
• /
• pp.129-138
• /
• 2013

The water uptake by fine aerosol in the atmosphere has been investigated at Gosan, Korea during ABC-EAREX 2005. The concentration of inorganic ion and carbon components, size distribution, and light scattering coefficients in normal and dry conditions were simultaneously measured for $PM_{2.5}$ by using a parallel integrated monitoring system. The result of this study shows that ambient fine particles collected at Gosan were dominated by water-soluble ionic species (35%) and carbonaceous materials (18%). In addition, it shows the large growth of aerosol in the droplet mode when RH is higher than 70%. Size distribution of the particulate surface area in a wider size range ($0.07-17{\mu}m$) shows that the elevation of RH make ambient aerosol grow to be the droplet mode one around $0.6{\mu}m$ or the coarse mode one, larger than $2.5{\mu}m$. Hygroscopic factor data calculated from the ratio of aerosol scattering coefficients at a given ambient RH and a reference RH (25%) show that water uptake began at the intermediate RH range, from 40% to 60%, with the average hygroscopic factor of 1.10 for 40% RH, 1.11 for 50% RH, and 1.17 for 60% RH, respectively. Finally, average chemical composition and the corresponding growth curves were analyzed in order to investigate the relationship between carbonaceous material fraction and hygroscopicity. As a result, the aerosol growth curve shows that inorganic salts such as sulphate and nitrate as well as carbonaceous materials including OC largely contribute to the aerosol water uptake.

• 한국대기환경학회지
• /
• 제26권1호
• /
• pp.69-76
• /
• 2010

While increased use of motor cycles in the recent years for various demands could worsen air quality, only few studies have been conducted on estimation of emission factors and characterization of emissions from motorcycle. In this study, emissions from selected six models of motorcycle based on largest market share and production rate were investigated. To investigate gaseous and carbonaceous air pollutants, such as carbon monoxide (CO), total hydrocarbon (THC), nitrogen oxide ($NO_x$), elemental carbon (EC) and organic carbon (OC), total 124 motorcycles between 2003 and 2007 model year were tested with regulatory driving conditions, such as CVS-40 and CVS-47 mode. These motorcycles were further sub-categorized based on their displacement (< 50 cc, 50~150 cc, and $\geq$ 150 cc), type of stroke (2- and 4 strokes) and model year (2003~2005 and 2006~2007). Tested motorcycles with recent model year (2006~2007) exhibited less emissions of regulatory gaseous and carbonaceous air pollutants compared to old model year (2003~2005). Chemical analysis showed that CO present in highest concentration followed by THC and $NO_x$ for all tested motorcycles. Interestingly, two strokes motorcycle produced higher THC emission but less CO and $NO_x$ than those of four strokes. For all types of displacement and stroke, emission factors (gram per kilometer) of THC and CO except $NO_x$ with recent model year (2006~2007) showed decreased trend compared to old model year (2003~2005). In addition to this, due to mixed combustion between gasoline fuel and lubricant, two strokes motorcycle showed OC > EC emission trend.

• 한국대기환경학회지
• /
• 제24권5호
• /
• pp.594-603
• /
• 2008

A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis, was applied to characterize four samples collected at an underground shopping area connected to Dongdeamun subway station, in January and May 2006. Based on the analysis of their chemical compositions of the samples, many distinctive particle types are identified and the major chemical species are observed to be soil-derived particles, iron-containing particles. sulfates. nitrates, and carbonaceous particles. which are encountered both in coarse and fine fractions. Carbonaceous particles exist in carbon-rich and organic. Soil derived particles such as aluminosilicates, AlSi/C, $CaCO_3\;and\;SiO_2$ are more frequently encountered in spring samples than winter samples. Nitrate- and sulfate-con taming particles are more frequently encountered in winter samples, and those nitrate- and sulfate-containing particles mostly exist in the chemical forms of $Ca(CO_3,\;NO_3),\;Ca(NO_3,\;SO_4),\;(Na,\;Mg)NO_3\;and\;(Mg,\;Na)(NO_3,\;SO_4)$. Fe-containing particles which came from nearby subway platform are in the range of about 10% relative abundances for all the samples. It is observed that nitrate- and sulfate-containing particles and carbonaceous particles are much more frequently encountered in indoor aerosol samples than in outdoor aerosols, implying that $NO_x,\;SO_x$, and VOCs at the underground shopping area were more partitioned into aerosol phase.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제15권3호
• /
• pp.34-43
• /
• 2010

The fate of hydrophobic organic contaminants (HOCs) in ground water is highly affected by the distribution and property of the carbonaceous materials (CMs) in subsurface sediments. CMs in soils consist of organic matters (e.g., cellulose, fulvic acid, humic acid, humin, etc.) and black carbon such as char, soot, etc. The distribution and property of CMs are governed by source materials and geological evolution (e.g., diagenesis, catagenesis, etc.) of them. In this study, the distribution and property of CMs in subsurface sediments near the Imjin river in the Republic of Korea and HOC sorption property to the subsurface sediments were investigated. The organic carbon contents of sand and clay/silt layers were about 0.35% and 1.37%, respectively. The carbon contents of condensed form of CMs were about 0.13% and 0.45%, respectively. The existence of black carbon was observed using scanning electron microscopes with energy dispersive spectroscopy. The specific surface areas (SSA) of CMs in heavy fraction(HFrCM) measured with N2 were $35-46m^2/g$. However, SSAs of those HFrCM mineral fraction was only $1.6-4.3m^2/g$. The results of thermogravimetric analysis show that the mass loss of HFrCM was significant at $50-200^{\circ}C$ and $350-600^{\circ}C$ due to the degradation of soft form and condensed form of CMs, respectively. The trichloroethylene (TCE) sorption capacities of sand and clay/silt layers were similar to each other, and these values were also similar to oxidzed layer of glacially deposited subsurface sediments of the Chanute Air Force Base (AFB) in Rantoul, Illinois. However, these were 7-8 times lower than TCE sorption capacity of reduced layer of the Chanute AFB sediments. For accurate prediction of the fate of hydrophobic organic contaminants in subsurface sediments, continuous studies on the development of characterization methods for CMs are required.

• 분석과학
• /
• 제18권4호
• /
• pp.309-319
• /
• 2005

본 연구는 흡착제와 기체상 분자의 흡착특성을 연구하기 위하여 탄소질 흡착제의 세공크기 및 흡착 온도와 압력에 따른 기체상 분자들의 흡착용량을 Crand Canonical Monte Carlo(GCMC) 분자모사 방법으로 예측하였다. 사용된 흡착질에 대한 분자구조 및 분자 분광학적 성질에 대해서는 범밀도함수이론(DFT)을 이용하여 계산하였다. 온도에 따른 흡착효과는 온도가 증가할수록 흡착량은 감소하는 경향을 보였으며, 흡착질의 크기, 극성, 그리고 흡착질간의 상호작용 등에 따라서도 흡착효과는 일정한 상관관계를 나타내는 것으로 예측되었다. 본 연구에 사용된 모든 경우에 대하여 탄소질 흡착제에 흡착되는 순서는 $NH_3$ < $H_2S$ < $CH_3SH$ 순으로 예측되었으며, 이러한 이론적 예측은 실험에 의한 관찰 결과와 정성적으로 잘 일치하는 것으로 나타났다.

• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2004년도 수소연료전지공동심포지움 2004논문집
• /
• pp.103-108
• /
• 2004

The present paper relates to an apparatus in which all carbonaceous material such as coal, oil, plastics and any substance having carbon atoms as part of its constituents are reformed(gasified) into syngas at temperature above $1,200^{\circ}C$(KR patent No.0391121, and PCT/KR2001/01717 and PCT/KR2004/001020). It comprises a single-stage reforming reactor without catalyst and a syngas burner as shown in Fig.2. syngas is combusted with $O_2$ gas in the syngas bunter to produce $M_2O$ and $CO_2$ gas with exothermic heat. Reaction products are introduced into the reforming reactor, reaction heat from syngas burner elevate the temperature of reactor above $1,200^{\circ}C$, and reaction products reduce carbonaceous material down to CO and $H_2$ gases. Reactants and heat necessary for the reaction are provided through the syngas burner only, Neither $O_2$ gas nor steam are injected into the reforming reactor. Reformer is made of ceramic inner lining and sst outer casing. Multiple syngas burners may be connected to the reforming reactor in order to increase the syngas output, and a portion of the product syngas is recycled into syngas burner. The present reformer as shown in Fig.2 is suitable to gasify carbonaceous wastes without secondary pollutants formed from oxidation. Further, it can be miniaturized to accompany a fuel cell system as shown in Fig.3 The output syngas may be used to drive a fuel cell and a portion of electrical power generated in a fuel cell is used to heat a compact reformer up to $1,200^{\circ}C$ so that gas/liquid fossil fuel can efficiently reformed into syngas. The fuel cell serves as syngas burner in Fig.2. The reformation reaction is sustained through recycling a portion of product syngas into a fuel cell and using a portion of electric power generated to heat the reformer for continuous operation. Such reforming reactor may be miniaturized into a size of PC, then you have a Personal Reformer(PR).

• Korean Chemical Engineering Research
• /
• 제44권6호
• /
• pp.669-675
• /
• 2006

본 연구에서는 휘발성 유기화합물 중 산업공정에서 사용빈도가 가장 높은 방향족류의 toluene, 케톤류의 MEK, 알코올류의 IPA에 의한 삼성분계 휘발성 유기화합물의 탄소계 흡착제에 대한 흡착특성 실험을 수행하였다. 입상 활성탄, 활성탄소섬유를 이용한 단일흡착제와 입상 활성탄과 활성탄소섬유를 동시에 적용한 조합흡착제를 사용하여 흡착성능과 흡착량을 비교 분석하였다. 실험용 흡착장치를 사용하여 단일성분 및 삼성분계 휘발성 유기화합물에 대한 흡착파과 실험을 수행하였으며, 각 경우에 대해 흡착량과 흡착성능을 비교하였다. 입상 활성탄은 toluene의 단일흡착 시 높은 흡착성능을 보였으나, IPA, MEK의 단일성분과 삼성분계 흡착실험에서는 상대적으로 낮은 성능을 보였다. 활성탄소섬유와 조합흡착제는 단일성분 흡착결과에서 모두 우수한 흡착성능을 보였으나, 삼성분계 흡착의 경우에는 흡착제의 경제성과 흡착효율을 고려하였을 때 입상 활성탄과 활성탄소섬유를 동시에 적용한 조합흡착제가 흡착제로서 가장 적합함을 확인할 수 있었다.