• Journal of Soil and Groundwater Environment
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• v.21 no.3
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• pp.14-20
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• 2016

Remediation of crude oil contaminated soil is complicate and hard to apply traditional methods because of its persistency, durability, and high viscosity. Therefore, in this study, the efficiency of crude oil contaminated soil remediation was tested by developing a pilot-scale thermal desorption system using the indirect heating method with an exhaust gas treatment. Under optimal condition drawed by temperature and retention time, the remedial efficiency of crude oil contaminated soil and treatability of exhaust gas were analyzed. Total Petroleum Hydrocarbon (TPH) concentration of crude oil contaminated soil was decreased to 69.7 mg/kg on average and the remedial efficiency was measured at 99.60%. Through the exhaust gas, 86.0% of Volatile Organic Compounds (VOC) was degraded and 97.16% of complex malodor was reduced under the suggested optimum operation condition. This study provides important basic data to be useful in scaling up of the indirect thermal desorption system for the remediation of crude oil contaminated soil.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.513-513
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• 2012

핵 융합로의 대면재질(Plasma Facing Material; PFM)은 고온의 플라즈마와 고 에너지의 이온들에 지속적으로 노출 된다. 특히 PFM은 흡착되는 기체 등에 의한 부식과 변형이 발생할 수 있다. 현재 핵 융합로 내부의 PFM으로 고려되고 있는 재질 중 하나인 고순도 탄소타일의 경우 고온의 수소동위원소 플라즈마에 직접적으로 노출되므로 이에 의한 탄소타일에 흡착되는 수소 등의 기체에 대한 정량적인 분석방법이 필요하다. 본 연구는 고순도 탄소타일 등과 같은 플라즈마 대면재료에 흡착되어 있는 물질의 정량적 분석이 가능한 TDA (Thermal Desorption Analyzer)의 개념 설계에 관한 것이다. TDA는 고온 가열($800^{\circ}C$ 이상) 및 시료 장착부 및 초고진공(~10-9 torr) 및 측정부의 두 부분으로 구성 하였다. TDA 설계시 고온 가열 및 시료 장착부는 시료 내부에 흡착되어 있는 기체의 효과적 탈착을 위한 가열 및 시료의 모양에 영향을 받지 않는 장착방법, 시료 장착부의 outgassing rate를 최소화 하는 재질 선정 등을 고려하였으며, 초고진공(~10-9 torr) 및 측정부는 초고진공 유지방법, 터보펌프 배기속도 실측을 위한 구조, 진공측정 ion 게이지, 잔류가스분석기(Residual Gas Analyzer)의 최적위치 설정 등을 고려하여 설계하였다. 개념 설계된 TDA에 대하여 발표하고자 한다.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.533-540
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• 2010

An activated carbon was tested for its ability to remove transition metal ions from aqueous solutions. Physical, chemical and liquid-phase adsorption characterizations of the carbon were done following standard procedures. Studies on the removal of Ni(II), Cu(II) and Fe(III) ions were attempted by varying adsorbate dose, pH of the metal ion solution and time in batch mode. The equilibrium adsorption data were fitted with Freundlich and Langmuir and the isotherm constants were evaluated, equilibrium time of the different three metal ions were determined. pH was found to have a significant role to play in the adsorption. The processes were endothermic and the thermodynamic parameters were evaluated. Desorption studies indicate that ion-exchange mechanism is operating.

• Journal of the Korean Vacuum Society
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• v.6 no.4
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• pp.298-307
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• 1997

TDS(Thermal Desorption Spectroscopy)system, for diagnosis of CRT manufacturing process, was designed and constructed. Outgassings and thermal desorptions from the part or materials of CRT can be measured and analysed with this system at various temperatures. The system is consisted of 3 parts, vacuum chamber and pumping system with variable conductance, sample heating stages & their controller, and outgassing measurement devices, like as ion gauge or quadrupole mass spectrometer. The ultimate pressure of the system was under $1{\times}10^{-7}$ Pa. With the variable conductance system, the effective pumping speed of the chamber could be controlled from sub l/s to 100 l/s. The effective pumping speed values were determined by dynamic flow measurement principle. The temperatures and ramp rate of sample were controlled by tungsten heater and PID controller up to 600℃ within ±1℃ difference to setting value. Ion gauge & QMS were calibrated for quantitative measurements. Some examples of TDS measurement data and application on the CRT process analysis were shown.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.757-772
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• 2013

In this study, a combination of sorbent tube (ST)-thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS) was used for quantitative analysis of liquid phase standards of 10 BVOC ((1) (+)-${\alpha}$-pinene, (2) (+)-${\beta}$-pinene, (3) ${\alpha}$-phellandrene, (4) (+)-3-carene, (5) ${\alpha}$-terpinene, (6) p-cymene, (7) (R)-(+)-limonene, (8) ${\gamma}$- terpinene, (9) myrcene, and (10) camphene). The results of BVOC calibration yielded comparatively stable pattern with response factor (RF) of 23,560~50,363 and coefficient of determination ($R^2$) of 0.9911~0.9973. The method detection limit (MDL) of BVOC was estimated at 0.03~0.06 ng with the reproducibility of 1.30~5.13% (in terms of relative standard error (RSE)). Emissions of BVOC were measured from four types of fruit samples ((1) tangerine (TO), (2) tangerine peel (TX), (3) strawberry (SO), and (4) sepals of strawberry (SX)). The sum of BVOC flux (${\sum}flux$ (BVOC) in ng/hr/g) for each sample was seen on the descending order of (1) TX=291,614, (2) TO=2,190, (3) SO=1,414, and (4) SX=2,093. If the results are compared between the individual components, the highest flux was seen from (R)-(+)-limonene (265,395 ng/hr/g) from TX sample.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1466-1473
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• 2012

Soft icecream is made by scraping an ice formed on the inside of the cylindrical evaporator, where R-404A is evaporating in the annulus. The heat transfer characteristics of the refrigerant evaporation and those during icecream formation were experimentally investigated. Results show that the refrigerant-side heat transfer coefficients are highly dependent on the location in the evaporator due to the complex annulus configuration. The heat transfer coefficient at the inlet is generally lower than those of other locations. The average heat transfer coefficient increases as heat flux increases or saturation temperature decreases. A correlation is developed to predict the refrigerant-side heat transfer coefficient. The icecream-side heat transfer coefficient oscillates continuously due to the periodic removal of ice formed on the surface. The average heat transfer coefficient during icecream formation is approximately 280 W/$m^2K$, and that during single-phase cooling increased from 150 W/$m^2K$ to 250 W/$m^2K$.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.4
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• pp.357-366
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• 2010

The purpose of this study is to evaluate a method for the measurement of N,N-Dimethylformamide (DMF) and to apply the method to the ambient air samples. For the determination of DMF together with other general VOCs (e.g., benzene, toluene, and xylenes), adsorption sampling and thermal desorption with GC/MS was used in this study. The sampling and analytical approaches tested in this study showed a good repeatability and linearity with lower detection limits of less than 0.35 ppb. Field measurements were carried out at three industrial sites (Daegu-Seongseo, Siwha and Banwall industrial complexes) and one residential site in Daegu city during a period from October 2006 to November 2008. DMF was detected in 71.8% of the total samples from the Seongseo industrial complex, well known for textile industry. In contrast, DMF was detected in only 20.4% and 12.9% of all the samples from the other two sites in Banwall and Siwha industrial complexes, respectively. This implies that sources of DMF should be strongly associated with textile industry. The mean concentration of DMF also appeared to be the highest in Seongseo site (5.95 ppb), followed by a residential site in Daegu (3.28 ppb), Banwall (0.88 ppb) and Siwha (0.55 ppb). In this study, we demonstrated the environmental significance of DMF in urban ambient air. To our knowledge, the DMF measurement introduced in this paper is the first case of an official report in Korea.

• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.72-90
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• 2001

This study was conducted to evaluate desorption efficiencies accuracy and precision by $CS_2$ and thermal desorption method for polar and non-polar organic solvents collected on activated carbon(AC), activated carbon fiber(ACF), carbosieve SIII, materials tested were Methyl alcohol, n-Hexane, Benzene, Trichloroethylene, Methyl isobutyl ketone and methyl cellosolve acetate and six different concentration levels of samples were made. The results were as follows ; 1. Accuracy on kind adsorbent and desorption method was low. In case of $CS_2$ desorption solvent, Overall B and Overall CV on AC and ACF were 43% and 6.63%, respectively. In case of thermal desorption method, accuracy of thermal desorption method appeared higher than solvent desorption method by AC 18.0%, 3.54%, ACF 2.6%, 2.57%, Carbosieve SIII 13.7% and 1.97%, respectively. 2. In the concentration level III, accuracy of thermal desorption method on adsorbent was in order as follow ; ACF > Carbosieve SIII > AC in the methyl alcohol and Carbosieve SIII > ACF > AC in the rest of them all subject material and Concentration levels showed good precision at EPA recommend standard (${\leq}{\;}30%$) 3. DEs by type of organic solvent adsorbent and desorption method are as follows ; In the case that desorption solvent is $CS_2$, DE of Methyl alcohol is AC 47.5%, DE of all materials is ACF about 50%. In the case of thermal desorption method, DE of Methyl alcohol is AC 82.0%, ACF 97.4%, Carbosieve SIII 86.3%. DE of the later case is prominently improved more than one of former. In particular, Except that DE of EGMEA is ACF 88.5%, DE of the rest of it is more than 95% which is recommend standard MDHS 72. With the result of this study, in order to measure various organic solvent occurring from the working environment, in the case of thermal desorption method, we can get the accurate exposure assessment, reduce the cost, and use ACF as thermal desorption sorbent which available with easy.

• Analytical Science and Technology
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• v.26 no.4
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• pp.287-297
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• 2013

The optimization of analytical method for the thermal desorption of seven VOCs (volatile organic compounds) by TD-GC/MS (thermal desorption-gas chromatograph-mass spectrometer) with solid phase sorbent tube, and comparative analysis for the determination of VOCs plotted by standard sorbent tubes prepared using both gas phase and liquid phase materials were investigated. The result of paired t-test showed that a liquid phase standard sorbent tube method was in agreement with a gas phase standard sorbent tube method for six species of VOCs including benzene, toluene, ethylbenzene, o-, m-, and p-xylene except for styrene at the significance level (${\alpha}=0.01$), while the 15.6% of difference in response factor between both of gas phase and liquid phase standard plotting for the determination of styrene showed that both methods were significantly different at the significance level. Therefore, the liquid phase standard plotting method was employed to reduce erroneous data for the determination of styrene including BTEX. Under the optimized analytical method by liquid phase standard sorbent tube, recovery was between $100{\pm}5%$ for 7 species of VOCs, reproducibility ranged from 0.3 to 7.7%, and method detection limit (MDL) ranged from $0.01{\mu}g/m^3$ for o-xylene to $0.27{\mu}g/m^3$ for toluene. The optimized standard method was applied to determine VOCs VOCs from indoor air of of dormitory, one bedroom apartment, and a new car.

• Analytical Science and Technology
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• v.17 no.2
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• pp.130-144
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• 2004

Recently, the air pollution in A and B industrial area has become one of the most important issues, then 60 VOCs in the area were measured using a highly sensitive method. The VOCs were adsorbed onto Carbotrap using air sampler and subsequently desorbed by a thermal desorber system into gas chromatograph-mass spectrometry (TDS-GC-MS). The peaks of all compounds had good chromatographic properties and offered very sensitive response for the EI-MS (SIM). Method detection limits (MDL) ranged from 0.01 to 0.1 ppt(v/v), and linearities of calibration curves were over 0.995. We analyzed total 90 atmosphere air samples of A and B industrial complex using the method. Benzene, toluene, ethylbenzene, xylene, n-hexane, fluorotrichloromethane, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, styrene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, sec-butylbenzene and naphthalen were identified as the major compounds in the air, and their average concentrations were 0.81, 5.02 1.30, 3.0, 0.81, 37.9, 0.07, 0.15, 0.15, 0.79, 0.06, 0.33, 0.03, 0.12, 0.23, and 0.35 ppb(v/v), respectively. The concentrations of VOCs were low in summer and high in fall or winter. When the concentrations detected in air compare with WHO's norm, no case exceed it.