• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.55-61
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• 2011

This study investigate the use of ultraviolet(UV) light with hydrogen peroxide($H_2O_2$) for Methyl Tert Butyl Ether(MTBE) degradation in photolysis reactor. The process in general demands the generation of OH radicals in solution at the presence of UV light. These radicals can then attack the MTBE molecule and it is finally destroyed or converted into a simple harmless compound. The MTBE removal by photolysis were mathematically described as the independent variables such as irradiation intensity, initial concentration of MTBE and $H_2O_2$/MTBE ratio, and these were modeled by the use of response surface methodology(RSM). These experiments were carried out as a Box-Behnken Design(BBD) consisting of 15 experiments. Regression analysis term of Analysis of Variance(ANOVA) shows significantly p-value(p<0.05) and high coefficients for determination values($R^2$=94.60%) that allow satisfactory prediction of second-order regression model. And Canonical analysis yields the stationery point for response, with the estimate ridge of maximum responses and optimal conditions for Y(MTBE removal efficiency, %) are $x_1$=25.75 W of irradiation intensity, $x_2$=7.69 mg/L of MTBE concentration and $x_3$=11.04 of $H_2O_2$/MTBE molecular ratio, respectively. This study clearly shows that RSM is available tool for optimizing the operating conditions to maximize MTBE removal.

• Journal of the Korean Solar Energy Society
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• v.21 no.2
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• pp.55-67
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• 2001

This study contains the photocatalytic degradation of methyl-tert-butyl ether(MTBE), one of water-contaminating substances, into $CO_2$. Herein was investigated factors, kinetics, and reaction pathways related with MTBE degradation. This works is possible to be applied in the field of environmental remediation such as undergroundwater purification with optimized system configuration in the near future.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.31-35
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• 2005

본 연구는 토양에 휘발유 첨가제인 MTBE와 휘발유의 주성분인 BTEX를 headspace 법에 의해 동시 분석하는 방법이다. 인산으로 pH를 2로 조절한 후 NaCl로 포화시킨 용액 5ml를 헤드스페이스 바이알에 보존제로 넣은 후 토양시료 약 2g을 이 용액에 침지시켜 시료 채취한 다음 헤드스페이스 장치에 넣고 $80^{\circ}C$에서 40분 가온하여 상부 기상의 일정량을 취해 GC-MS (SIM)으로 분석하였다. 본 분석법에 의한 검출한계는 methyl-tert-butyl ether(MTBE)와 benzene, toluene, ethylbenzene, o,m,p-xylene(BTEX)이 각각 0.1, 0.1, 0.1, 0.2, 0.1, 0.2 ng/g이었고, 직선성은 0.995이상이었으며, 재현성도 10%내외의 정밀한 값을 보였다. 실제 시료를 분석한 결과, MTBE가 3-6,993 ng/g의 농도분포를 보였고 total BTEX는 1 ng/g으로 검출되었다. 이 방법은 빠르고 정밀 정확한 분석법으로 공정시험법으로 활용가치가 높다.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.197-203
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• 2005

This paper investigates the effect of oxygen composition in mixed fuel on the exhaust emissions for the direct injection diesel engine. These effects were tested to estimate the change in engine performance and exhaust emission characteristics when commercial diesel fuel and oxygenates blended fuels at a certain fuel and mixed ratio are used. Individual hydrocarbons $(C_1-C_6)$ in exhaust gases, as well as the total amount of hydrocarbons, were analyzed by using gas chromatography to find the mechanism by which smoke emission was remarkably reduced for various oxygenated fuels. The chromatograms between a diesel fuel and a diesel fuel blended DGM (diethylene glycol dimethyl ether), MTBE (methyl tert-butyl ether) and EGBE (ethylene glycol mono-n-butyl ether) were compared. The results showed that the number of individual hydrocarbons as well as the total number of hydrocarbons of oxygenated fuel reduced more remarkably than those of diesel fuel.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.207-208
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• 2006

Earthworms have been widely used as bioindicators for soil ecotoxicity assessment. Ecotoxicity of methyl tert-butyl ether(MTBE) to terrestrial organisms were evaluated by- earthworm assay. Test earthworm species were Perionyx excavatus and Eisenia andrei. The. toxicity test was performed based on a OECD guideline No. 207 with slight modification. Mortality and abnormal morphology of earthworms exposed to different concentrations of MTBE were measured. Toxic levels of MTBE were determined by measuring the median lethal concentration (LC5O) after 72 hours. The toxicity data was statistically analyzed by Trimmed Spearman-Harbor method. This study showed that, P. excavatus is more sensitive to E. andrei, and that earthworm assay can be a good protocol to evaluate the soils contaminated gasoline components.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.387-392
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• 2005

Recently, dimethyl carbonate (DMC) is considered as an alternative of MTBE (methyl tert-butyl ether), additive for non-leaded gasoline with their fast biodegradation rate and low toxicity. DMC is usually synthesized so far by oxidative carbonylation of methanol, and recently developed synthetic process is also started with methanol. Since the phase equilibria of the system, consisted of DMC and methanol or other reaction products on different temperature and pressure is necessary for the optimum separation process design and operation. However the reported phase equilibria and physical properties for DMC mixtures in the Dortmund Data Bank (DDB; thermodynamic property data bank) are quite rare. Besides, infinitely dilute properties are not found. In this work, isothermal vapor-liquid equilibria at 333.15 K for methanol+DMC binary system and mixing properties, excess molar volume and viscosity deviation at 298.15 K are directly measured and correlated. Additionally, infinitely dilute activity coefficient of methanol in the DMC solvent at three different temperatures are measured and compared with predicted values using modified UNIFAC (Dortmund).

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.15-21
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• 2012

MTBE (Methyl tertiary-butyl ether) has been commonly used as an octane enhancer to replace tetraethyl lead in gasoline, because MTBE increases the efficiency of combustion and decreases the emission of carbon monoxide. However, MTBE has been found in groundwater from the fuel spills and leaks in the UST (Underground Storage Tank). Fenton's oxidation, an advanced oxidation catalyzed with ferrous iron, is successful in removing MTBE in groundwater. However, Fenton's oxidation requires the continuous addition of dissolved $Fe^{2+}$. Zero-valent iron is available as a source of catalytic ferrous iron of MFO (Modified Fenton's Oxidation) and has been studied for use in PRBs (Permeable Reactive Barriers) as a reactive material. Therefore, this study investigated the condition of optimization in MFO-PRBs using waste zero-valent iron (ZVI) with the waste steel scrap to treat MTBE contaminated groundwater. Batch tests were examined to find optimal molar ratio of MTBE : $H_2O_2$ on extent to degradation of MTBE in groundwater at pH 7 with 10% waste ZVI. As the results, the ratio of optimization of MTBE to hydrogen peroxide for MFO was determined to be 1:300[mM]. The column experiment was conducted to know applicability of MFO-PRBs for MTBE remediation in groundwater. As the results of column test, MTBE was removed 87% of the initial concentration during 120days of operational period. Interestingly, MTBE was degraded not only within waste ZVI column but also within sand column. It means the aquifer may affect continuously the MTBE contaminated groundwater after throughout the waste ZVI barrier. The residual products showed acetone, TBF (Tert-butyl formate) and TBA (Tert-butyl acetate) during this test. The results of the present study showed that the recycled materials can be effectively used for not only a source of catalytic ferrous iron but also a reactive material of the MFO-PRBs to remove MTBE in groundwater.

• Journal of Soil and Groundwater Environment
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• v.15 no.1
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• pp.9-18
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• 2010

In this study, Solid-phase micro-extraction (SPME) with Gas Chromatograph using Flame Ionization Detector (GC/FID) was studied as a possible alternative to liquid-liquid extraction for the analysis of Methyl tert-butyl ether (MTBE) and Tertiary-butyl ether (TBA) in water and an optimization condition of trace analysis of MTBE and TBA using the design of experiment (DOE) was described. The aim of our research was to apply experimental design methodology in the optimization condition of trace analysis of fuel oxygenated compounds in soil-phase microextraction with GC/FID. The reactions of SPME were mathematically described as a function of parameters of Temp ($X_1$), Volume ($X_2$), Time ($X_3$) and Salt ($X_4$) being modeled by the use of the partial factorial designs, which was used for fitting 2nd order response surface models and was alternative to central composite designs. The model predicted agreed with the experimentally observed result ($Y_1$(MTBE, $R^2$ = 0.96, $Y_2$ (TBA, $R^2$ = 0.98)). The estimated ridge of the expected maximum responses and optimal conditions for MTBE and TBA were 278.13 and (Temp ($X_1$) = $48.40^{\circ}C$, Volume ($X_2$) = 73.04 mL, Time ($X_3$) = 11.51 min and Salt ($X_4$) = 12,50 mg/L), and 127.89 and (Temp ($X_1$) = $52.12^{\circ}C$, Volume ($X_2$) = 88.88mL, Time ($X_3$) = 65.40 min and Salt ($X_4$) = 12,50 mg/L), respectively.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.53-60
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• 1997

1. 서론 : 촉매막기술은 반응과 분리공정을 동시에 하나의 장치에서 수행할 수 있기 때문에 한 개의 공정을 줄일 수 있는 효과적인 에너지 절약형 기술이다. 생성물중의 적어도 하나가 선택적으로 막을 통해 투과되기 때문에 가역반응의 경우에는 비가역반응에 가까운 거동을 보이게 된다[1-5]. 본 연구는 12-텅스토인산($H_3PW_{12}O_{40}$)를 촉매로 사용하고 막반응시를 비활성촉매막반응기(IMRCF, Inert membrane reactor with catalyst in the feed side)형태, 막으로는 PSF(Polysulfone), PPO(Polyphenylene Oxide)를 사용하여 MTBE(Methyl tert-butyl ether)분해반응을 모사하였다. 막반응기에서 생성된 생성물을 선택적으로 분리해냄으로 인하여 전환율은 고정층보다 증가하였는데 반응온도가 증가할수록, 반응물의 분압은 낮을수록 증가하였다. 반응온도가 높아짐에 따라 막반응기에서의 전환율은 고정층반응에서 나타나는 전환율과의 차이가 줄어드는 것을 볼 수 있었다. 위와같은 결과에 따라서 MTBE 반응물의 분해로 생성되는Isobutene의 수율이 90$\circ$C 이상의 반응온도에서 촉매/반응물비에 대한 최적조건이 나타나는 것을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1315-1322
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• 2006

The following study describes the gas chromatography-mass spectrometry (GC-MS) based screening and confirmation analysis of urinary androgenic steroids. Four commercially available solid-phase extraction (SPE) cartridges, Serdolit PAD-1, Sep-pak $C_{18}$, amino-propyl, and Oasis HLB, and three different extractive organic solvents, diethyl ether, methyl tert-butyl ether (MTBE), and n-pentane, were tested for sample preparation. Overall, Oasis HLB combined with MTBE extraction provided the highest recoveries in 39 of 46 total androgenic steroids examined and it showed a good extraction yield (>82.1%) for polar steroids, such as metabolites of fluoxymesterone, oxandrolone, and stanozolol, which gave a poor recovery in both n-pentane (9.2-64.3%) and diethyl ether (22.2-73.6%) extractions. All SPE sorbents tested showed potential, because they were efficient in extraction for most or selective steroids. When applied to positive urine samples based on the results obtained, the present method allowed selective and sensitive analysis for detection of urinary androgenic steroids. The experiments showed that the high-resolution MS method is clearly more efficient than the low-resolution MS technique for the detection of many urinary steroids. However, comprehensive sample clean-up procedures also might be needed especially in confirmation analysis to increase detectability.