• Journal of the Korean Society of Combustion
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• v.15 no.4
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• pp.9-14
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• 2010

Numerical simulations of freely propagating fuel-rich $CH_4/CH_3Cl$ premixed flames were performed at atmospheric pressure in order to understand the effect of the oxygen enrichment on the production of PAH. A chemical kinetic mechanism was used, which involved 157 gas-phase species and 1693 forward reactions. The calculated flame speeds were compared with the experiments for the flames established on the equivalence ratios of 1~1.6, the results of which were in good agreement. As the level of oxygen enrichment was increased, the concentrations of one or four ring aromatic hydrocarbons were decreased. This might cause the fact that the contribution of PAH species to soot was weakened.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.245-246
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• 2000

산업의 발달로 인하여 유해폐기물의 양과 종류가 날로 증가하고 있다. 특히 본 연구에서 사용한 $CCl_4$는 염화탄화수소(chlorinated hydrocarbons, CHCs)(Elizabeth 와 Catherine) 계통의 대표적인 유해폐기물이며 플라스틱제조업, 제초제와 살충제를 제조하는 농약제조업, 유기용제 제조업 등에서 다량 배출되며 해마다 발생량이 증가하는 추세이다. 최근까지 대부분의 유해폐기물을 처리가격의 저렴성과 기술적으로 어려움이 적은 매립 및 밀봉등의 방법과 물리화학적 방법으로 처리하였으나 앞으로는 소각에 의한 처리방법이 증가되리라 예상된다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.269-270
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• 2000

산업의 발달로 인하여 유해폐기물의 양과 종류가 날로 증가하고 있다. 유해폐기물은 고온에서 분해가 어렵고 연소시 인체에 유해한 성분을 생성하는 Chlorinated Hydrocarbons(Gupta,A.K. and Valeiras,H.A,1984)과 Acetonitrile, 연소성을 저해하는 $SF_6$ 등이 있다. 지금까지 유해폐기물은 처리가격의 저렴성과 기술적 어려움이 적은 매립 및 밀봉등의 방법에 의존해 왔으나, 최근 들어 소각에 의한 처리가 증가추세에 있다. (중략)

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.723-730
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• 2007

This study was conducted to develop a combined method for remediating a Chlorinated Aliphatic Hydrocarbons (CAHs) mixtures-contaminated aquifer. The process is consist of two processes. A chemical process (1st) using natural zinc ores for reducing higher concentrations of CAH mixtures to the level at which biological process is feasible; and A biological process (2nd) using aerobic cometabolism for treating lower concentration of CAH mixtures (less than 1 mg/L). Natural zinc ore showed relatively high transformation capacity, average dehalogenation percentage, and the best economic efficiency in previously our study. To evaluate the feasibility of the process, we operated two columns in series (that is, chemical and biological columns). In the first column filled with natural zinc ore and sand, CAH mixtures were effectively transformed with more than 95% efficiency, the efficiency depends on the Empty Bed Contact Time (EBCT) and the mass of zinc ore packed. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) analysis were performed to make sure whether natural zinc ore played an key role in the dechlorination of the CAH mixtures. The characteristics of zinc metal surface changed after exposure to CAHs due to oxidation of $Zn^0$ to $Zn^{2+}$. In the biological column injecting propane, DO and effluent of the chemical column, only 1,1,1-TCA was cometabolically transformed. Consequently, the combined process would be effective to remediate an aquifer contaminated with high concentrations of CAH mixtures.

• Clean Technology
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• v.16 no.3
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• pp.198-205
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• 2010

Two sets of thermal reaction experiment for chlorinated hydrocarbons were performed using an isothermal tubular-flow reactor in order to investigate thermal decomposition, including product distribution of chlorinated hydrocarbons. The effects of $H_2$ or Ar as the reaction atmosphere on the thermal decomposition and product distribution for dichloromethane($CH_2Cl_2$) was examined. The experimental results showed that higher conversion of $CH_2Cl_2$ was obtained under $H_2$ atmosphere than under Ar atmosphere. This phenomenon indicates that reactive-gas $H_2$ reaction atmosphere was found to accelerate $CH_2Cl_2$ decomposition. The $H_2$ plays a key role in acceleration of $CH_2Cl_2$ decomposition and formation of dechlorinated light hydrocarbons, while reducing PAH and soot formation through hydrodechlorination process. It was also observed that $CH_3Cl,\;CH_4,\;C_2H_6,\;C_2H_4$ and HCl in $CH_2Cl_2/H_2$ reaction system were the major products with some minor products including chloroethylenes. The $CH_2Cl_2$/Ar reaction system gives poor carbon material balance above reaction temperature of $750^{\circ}C$. Chloroethylenes and soot were found to be the major products and small amounts of $CH_3Cl$ and $C_2H_2$ were formed above $750^{\circ}C$ in $CH_2Cl_2$/Ar. The thermal decomposition reactions of chloroform($CHCl_3$) with argon reaction atmosphere in the absence or the presence of $CH_4$ were carried out using the same tubular flow reactor. The slower $CH_3Cl$ decay occurred when $CH_4$ was added to $CH_3Cl$/Ar reaction system. This is because :$CCl_2$ diradicals that had been produced from $CHCl_3$ unimolecular dissociation reacted with $CH_4$. It appears that the added $CH_4$ worked as the :$CCl_2$ scavenger in the $CHCl_3$ decomposition process. The product distributions for $CHCl_3$ pyrolysis under argon bath gas were distinctly different for the two cases: one with $CH_4$ and the other without $CH_4$. The important pyrolytic reaction pathways to describe the important features of reagent decay and intermediate product distributions, based upon thermochemistry and kinetic principles, were proposed in this study.

• Membrane Journal
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• v.9 no.2
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• pp.114-125
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• 1999

Dense polymer membranes were made from vanous silicone polymers such as poly(1-trimethylsilyl-1-propyneHPTMSP), poly(dimethylsiloxaneHPDMS), PTMSP- g-PDMS. These membranes were evaluated in terms of the removal of chlorinated organic hydrocarbons such as chloroform, trichloroethylene(TCE), perchloroethylene(PCE) from water by pervaporation. It was possible for membranes used in this study to remove PCE selectively which is dissolved small quantity in water among other separable solutes. PTMSP membranes exhibited a remarkable decay in permeability with time because of the free volume decreases. However, PTMSP-g-PDMS membrane underwent no physical aging and showed the stable flux behavior. From the results of the contact angle measurement, polymeric membranes used in this study showed affinity with solutes for separation and no affinity with water. The relative swelling degree was directly related to the selectivity, while it has no influence on the flux.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.287-292
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• 2002

Lignin-peroxidase (LiP) has been considered as one of the most important industrial enzymes for biodegradation of various recalcitrant toxic compounds such as chlorinated aromatic hydrocarbons and azo-dyes. Recently, several soil actinomycetes have been reported to secrete a functionally-similar lignin-peroxidase called actinomycetes lig-nin-peroxidase (ALiP). In this manuscript, we isolated over 100 morphologically distinct actinomycetes from the contaminated soils around 10 different gas stations located nearby the Kyung-An river. Among these actinomycetes screened based on the congo-red dye-decolorization activities, one newly-isolated actinomycetes named SMA-2 showed the most significant dye-decoloring activity on the congo-red plate as well as a significant ALiP activity in a yeast-extract-malt-extract liquid media supplemented with starch. The optimum SMA-2 culture condition fur ALiP production was determined and the kinetic parameters fur the SMA-2 AkIP activity were characterized. The optimally-cultured SMA-2 also exhibited the oxidation activities toward various recalcitrant aromatic compounds including phenol, 2- chlorophenol, 4- chlorophenol, 2,4- dichlorophenol ,2,6- dichlorophenol, and 2,4, f-trichlorophe - not, suggesting a potential application of SMA-2 for contaminated soil bioremediation.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.333-336
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• 2005

32 Volatile organic compounds(VOCs) were measured by thermal desorption/gas chrornatography/mass spectrometry in normal houses, new and sick houses. The sum concentrations of aromatic hydrocarbons in living room of new and sick houses showed 606 ${\mu}g/m^3$ and 645 ${\mu}g/m^3$, respectively, These figures were about 40 times higher than the values 14 ${\mu}g/m^3$ in normal houses. Among the chlorinated hydrocarbons trichloroethylene in the new and sick houses were at least 50-100 times higher than the mean concentrations in normal houses. But no significant differences could be shown for the concentration of VOCs in indoor air between new houses and sick houses (p<0.05).

• Journal of Environmental Science International
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• v.13 no.9
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• pp.767-777
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• 2004

This study evaluated the technical feasibility of the application of $TiO_2$ photocatalysis for the removal of volatile hydrocarbons(VHC) at low ppb concentrations commonly associated with non-occupational indoor air quality issues. A series of experiments was conducted to evaluate five parameters (relative humidity (RH), hydraulic diameter (HD), feeding type (FT) of VHC, photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) for the PCO destruction efficiencies of the selected target VHC. None of the target VHC presented significant dependence on the RH, which are inconsistent with a certain previous study that reported that under conditions of low humidity and a ppm toluene inlet level, there was a drop in the PCO efficiency with decreasing humidity. However, it is noted that the four parameters (HD, RM, FT and IPS) should be considered for better VHC removal efficiencies for the application of $TiO_2$ photocatalytic technology for cleansing non-occupational indoor air. The PCO destruction of VHC at concentrations associated with non-occupational indoor air quality issues can be up to nearly 100%. The amount of CO generated during PCO were a negligible addition to the indoor CO levels. These abilities can make the PCO reactor an important tool in the effort to improve non-occupational indoor air quality.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.5
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• pp.577-583
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• 2007

To overcome certain disadvantages of past typical control techniques for toxic contaminants emitted from various industrial processes, the current study was conducted to establish a thermal catalytic system using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst and to evaluate catalytic thermal destruction of five chlorinated hydrocarbons[chlorobenzene(CHB), chloroform(CHF), perchloroethylene (PCE), 1,1,1-trichloroethane(TCEthane), trichloroethylene(TCE)]. In addition, this study evaluated the catalyst poison effect on the catalytic thermal destruction. Three operating parameters tested for the thermal catalyst system included the inlet concentrations, the incineration temperature, and the residence time in the catalyst system. The thermal decomposition efficiency decreased from the highest value of 100% to the lowest value of almost 0%(CHB) as the input concentration increased, depending upon the type of chlorinated compounds. The destruction efficiencies of the four target compounds, except for TCEthane, increased upto almost 100% as the reaction temperature increased, whereas the destruction efficiency for TCEthane did not significantly vary. For the target compounds except for TCEthane, the catalytic destruction efficiencies increased up to 30% to 97% as the residence time increased from 10 sec to 60 sec, but the increase of destruction efficiency for TCEthane stopped at the residence time of 30 sec, suggesting that long residence times are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Conclusively, the current findings suggest that when applying the transition-metal catalyst for the better destruction of chlorinated hydrocarbons, VOC type should be considered, along with their inlet concentrations, and reaction temperature and residence time in catalytic system. Meanwhile, the addition of high methyl sulfide(1.8 ppm) caused a drop of 0 to 50% in the removal efficiencies of the target compounds, whereas the addition of low methyl sulfide (0.1 ppm), which is lower than the concentrations of sulfur compounds measured in typical industrial emissions, did not cause.