• Korean Chemical Engineering Research
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• 제55권6호
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• pp.807-815
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• 2017

본 연구에서는 회전증발에서 건조 온도에 따른 파클리탁셀의 잔류 펜탄 제거 효율에 대해 조사하였으며 건조 공정에 대한 동역학 및 열역학적 해석을 수행하였다. 모든 온도(25, 30, 35, 40, $45^{\circ}C$)에서 건조 초기에 많은 양의 잔류용매가 제거되었으며 건조 온도가 증가할수록 건조 효율은 증가하였다. 동역학적 해석을 위해 실험데이터 값을 다섯 종류의 건조 모델식(Newton, Page, Modified Page, Henderson and Pabis, Geometric)에 적용하였으며, 이 중 Henderson and Pabis 모델이 큰 결정계수 값과 작은 평균평방근편차 RMSD 값을 가져 가장 적합함을 확인하였다. 또한 열역학적 해석을 수행한 결과, 회전증발에서의 활성화 에너지 $E_a$는 4.9815 kJ/mol이었으며, 표준 Gibbs 자유에너지 변화(${\Delta}G^0$)는 음수 값인 반면 표준 엔탈피 변화(${\Delta}H^0$)와 표준 엔트로피 변화(${\Delta}S^0$)는 양수 값을 나타내어 건조 공정이 자발적 흡열반응이며 비가역적으로 수행됨을 알 수 있었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.29-32
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• 2004

Gaseous partitioning tracer test has been used for determining the volume and spatial distribution of residual non-aqueous phase liquid (NAPL) in the unsaturated soils. In this study, an experimental method for measuring the content of gas-exposed NAPL as well as that of total NAPL in a sand during air sparging was developed. Two different gaseous phase NAPL-partitioning tracers were used; n-pentane, with very low water solubility, was used as the tracer that partitions into NAPL that is only in contact with the mobile gas, and chloroform, with fairly good water solubility, was selected for detecting total NAPL content in the sand. Helium and difluromethanewere used as the non- reactive tracer and water-partitioning tracers, respectively. Using n-decane as a model NAPL (NAPL saturation of 0.018), 25.6% of total NAPL was detected by n-pentane at the water saturation of 0.68. Oniy 9.1% of total NAPL was detected by n-pentane at the water saturation of 0.84. This result implies that the quantity of gas-exposed NAPL increased about three times when the water saturation decreased from 0.84 to 0.68. At the water saturation of 0.68, more than 90% of total NAPL was detected by chloroform while 65.8% of total NAPL was detected by chloroform at the water saturation of 0.84. Considering that the removal rate of NAPL during air sparging for NAPL-contaminated aquifer is expected to be greatly dependent upon the spatial arrangement of NAPL phase with respect to the mobile gas, this new approach may provide useful information for investigating the mass transfer process during air-driven remedial processes fer NAPL-contaminated subsurface environment.

• Food Science and Biotechnology
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• 제14권4호
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• pp.456-460
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• 2005

To enforce the maximum residue limit for residual hexane (0.005 g/kg) in commercially available Korean vegetable oil, convenient and accurate quantification methods were investigated. Using dual surrogate standards, pentane and heptane were dissolved in ethanol, and then added to hexane-tree sunflower oil for setting up the calibration curve. Gas Chromatograph-Flame Ionization Detector with a porous layer open tubular column, indicated good chromatographic separation of hexane from other inhibiting matrix components. The lowest calibration level was $0.5\;{\mu}g/g$, not exceeding a relative standard deviation of 10% (RSD%), and 1.0\;{\mu}g/g$ not exceeding a deviation of 22% RSD% using heptane as an internal standard for the Static headspace analysis by using a headspace auto-sampler and manual injection, respectively. The residual hexane was detected in nine of the samples among 87 vegetable oil samples purchased on the local market.

• 분석과학
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• 제17권6호
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• pp.527-531
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• 2004

Treatment with aqueous sodium hydroxide solution plays an important role to impart certain desirable properties - feel and luster on the surface of polyester fiber. In this process alkali wastewater contains disodium terephthalate, ethylene glycol (EG) and residual sodium hydroxide. In this paper we report a new method containing the pretreatments of derivatization with benzoyl chloride and solvent extraction using pentane. The calibration curve of EG determined by GC/MS-SIM shows a good linearity in the range of 0.1 to $25{\mu}g/mL$ having the standard deviation of ${\leq}8.7%$. The recovery and the detection limit of this method are 91.9-93.7% and $0.05{\mu}g/mL$ respectively.