• 자원리싸이클링
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• 제23권1호
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• pp.17-24
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• 2014

Nd와 Pr이 함유된 모나자이트 샌드의 염산 침출용액에서 PC88A와 D2EHPA를 사용하여 두 금속을 분리하기 위한 용매추출실험을 수행하였다. 이러한 목적을 위해 수상의 pH에 따른 PC88A와 D2EHPA의 비누화가 두 금속의 추출 및 분리에 미치는 영향을 조사하였다. 본 연구에서 수행한 실험조건에서 Nd의 분배계수가 Pr의 분배계수보다 크며, 수상의 pH가 높을수록 분리인자가 증가하였다. PC88A에 비해 비누화시킨 PC88A로 추출하는 경우 분배계수와 분리인자 모두 증가하였다. D2EHPA의 비누화율은 두 금속의 추출에는 영향을 미치지만, 분리인자에는 큰 변화가 없었다.

• 생약학회지
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• 제43권1호
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• pp.16-21
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• 2012

The characteristics of decoction water are important for the extraction of herbal drugs. In this study, the relationship between the characteristics of water and extraction efficiency of bioactive compounds from Corydalis tuber was investigated. Six different types of decoction water, including three types of mineral water from Jeju Island and three types of bottled water sold in market, were used as decoction water for the extraction of bioactive compounds from Corydalis tuber. The contents of minerals in six types of water were analyzed by ICP-AES and ICP-MS; the contents of extracted bioactive compounds were analyzed by HPLC. Multivariate analysis of variance was used to analyze the differences in total extraction and bioactive compounds extracted with six types of water. Multiple factor analysis was used to analyze the relationship among the pH, content of mineral, anion, total extractions and content of bioactive components as factors. There was a significant difference among the six types of water in the total extracts and the bioactive compounds. The results proved that the content of extracted compounds from Corydalis tuber was influenced by the types of decoction water.

• 자원리싸이클링
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• 제14권2호
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• pp.33-42
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• 2005

Nd와 Sm이 혼합된 염산용액에서 PC88A에 의한 두 금속의 분리에 대한 실험을 수행하였다. 또한 PC88A의 비누화가 두 금속의 추출 및 분리에 미치는 영향을 조사하였다. 본 연구에서 수행한 실험조건에서 Sm의 분배계수가 Nd의 분배계수보다 크며, 분리인자는 수상의 pH에 따라 증가하였다. 비누화 PC88A로 추출하는 경우 PC88A로 추출하는 경우에 비해 분배계수와 분리인자 모두 증가하였다. PC88A와 비누화 PC88A에 의한 추출시 초기추출조건으로부터 Nd와 Sm의 분배계수와 분리인자를 예측할 수 잇는 모델을 개발하였다. 본 연구에서 개발된 모델을 초기추출조건에 적용하여 예측한 Nd와 Sm의 분배계수는 실험으로 측정한 값과 서로 잘 일치하였다.

• Natural Product Sciences
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• 제21권2호
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• pp.141-145
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• 2015

Hesperidin, which is the most abundant flavonoid of Citrus unshiu (Rutaceae), has been reported to possess diverse activities and widely used as functional foods and cosmetics. For the development of functional products, extraction procedure is indispensable. Extraction conditions affect the composition of extract as well as its biological activity. Therefore, we tried to optimize extraction conditions such as extraction solvent, extraction time and extraction temperature for maximum yield of hesperidin using response surface methodology with threelevel-three-factor Box-Behnken design (BBD). Regression analysis showed a good fit of the experimental data and the optimal condition was obtained as ethanol concentration, 59.0%; temperature $71.5^{\circ}C$ and extraction time, 12.4 h. The hesperidin yield under the optimal condition was found to be $287.8{\mu}g$ per 5 mg extract, which was well matched with the predicted value of 290.5 μg. These results provides optimized extraction condition for hesperidin and might be useful for the development of hesperidin as functional products like health supplements, cosmetics and medicinal products.

• 산업식품공학
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• 제21권3호
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• pp.256-266
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• 2017

This study was designed to optimize ethanol extraction process of unfertilized corn silk (UCS) to maximize phytochemical contents and bioactivities. The response surface methodology (RSM) with central composite design (CCD) was employed to obtain the optimal extraction conditions. The influence of ethanol concentration, extraction temperature and extraction time on total polyphenol contents, total flavonoid contents, maysin contents, 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activities and tyrosinase inhibition were analyzed. For all dependable variables, the most significant factor was ethanol concentration followed by extraction temperature and extraction time. The following optimum conditions were determined by simultaneous optimization of several responses with the Derringer's desirability function using the numerical optimization function of the Design-Expert program: ethanol concentration 80.45%, extraction temperature $53.49^{\circ}C$, and extraction time 4.95 h. Under these conditions, the predicted values of total polyphenol contents, total flavonoid contents, maysin contents, DPPH radical scavenging activity and tyrosinase inhibition were $2758.74{\mu}g\;GAE/g$ dried sample, $1520.81{\mu}g\;QUE/g$ dried sample, 810.26 mg/100g dried sample, 56.86% and 43.49%, respectively, and the overall desirability (D) was 0.74.

• Archives of Metallurgy and Materials
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• 제65권4호
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• pp.1273-1276
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• 2020

Liquid metal extraction (LME) process results in 100% neodymium (Nd) extraction but the highest extraction efficiency reported for Dysprosium (Dy) so far is 74%. Oxidation of Dy is the major limiting factor for incomplete Dy extraction. In order to enhance the extraction efficiency and to further investigate the limiting factors for incomplete extraction, experiments were carried out on six different particle sizes of under 200 ㎛, 200-300 ㎛, 300-700 ㎛, 700-1000 ㎛, 1000-2000 ㎛ and over 2000 ㎛ at 900℃ with magnesium-to-magnet scrap ratio of 15:1 for 6, 24 and 48 hours, respectively. This research identified Dy₂Fe₁₇ in addition to Dy₂O₃ phase to be responsible for incomplete extraction. The relationship between Dy₂Fe₁₇ and Dy₂O₃ phase was investigated, and the overall extraction efficiency of Dy was enhanced to 97%.

• 자원리싸이클링
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• 제24권5호
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• pp.80-86
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• 2015

In, Ga, Fe, Al이 함유되어 있는 혼합용액으로부터 In을 분리하기 위해 D2EHPA를 이용한 용매추출 연구를 수행하였으며, In의 추출에 대한 수상의 HCl 및 추출제 농도 효과를 확인하였다. In과 Ga의 추출률은 HCl 농도의 감소에 따라 증가하였지만, Fe와 Al의 추출률에는 큰 영향을 미치지 않았다. In과 Ga의 분리인자($D_{In}/D_{Ga}$)는 1.0 M D2EHPA, 0.5 M HCl조건에서 115로 나타났다. 즉, D2EHPA는 혼합용액으로부터 In을 분리하는 추출제로 적합하며, 추출률 및 분리인자는 HCl 및 추출제의 농도 조절을 이용하여 조절할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1945-1950
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• 2010

Solvent extraction experiments of Pt(IV), Pd(II) and Rh(III) by Alamine336 were performed from the mixed chloride solutions. In the HCl concentration range from 1 to 5 M, most of Pt and Pd were extracted from the mixed solutions. However, the extraction percentage of Rh was much smaller than that of Pt and Pd. Lower concentration of Alamine336 in strong HCl solution led to higher separation factor of Rh from Pt and Pd. Adding $SnCl_2$ to the mixed solutions increased the extraction percentage of Rh, while the extraction percentage of Pt and Pd was little affected. Our results showed that selective separation of Rh or coextraction of the three platinum group metals from the mixed solution would be possible by adjusting the extraction conditions.

• 한국대기환경학회지
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• 제16권6호
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• pp.595-606
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• 2000

In order to compare analytical conditions for measuring PAHs(polycyclic aromatic hydrocarbons) in ambient air, a series of experiment were conducted using three different types of extraction methods that include:(1) accelerated solvent extraction (ASE), (2) soxhlet, and (3) sonification methods. Efficiency and relevant analytixal parameters for each of these methods were examined on five different types of solvents that include:(1) 10% diethyl ether in n-hexane(v/v), (2) dichloromethane, (3)cyclohexane.(4) toluene, and (5) Benzene: ethanol (4:1). Comparison of extraction efficiency for various combinations between methods and solvents was made through an application of both internal and external standard calibration techniques. The extraction efficiency tests, when checked using both internal and external standards, allowed us to derive meaningful comparison among different techniques and among solvents.

• 대한본초학회지
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• 제29권6호
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• pp.1-6
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• 2014

Objectives : This study was aimed to compare Gyejibokryeong-hwan (GBH) decoctions produced using different pressure levels for various extraction times to find the optimal extraction conditions through extraction yield, total soluble solids content (TSSC), hydrogen ion concentration (pH), and the contents of chemical compounds. Methods : Decoctions of GBH were prepared under the pressure levels of 0 or $1kgf/cm^2$ for 30-180 min using water as extraction solvent. The extraction yield, TSSC, and pH were measured, and the amounts of the chemical compounds were determined using high performance liquid chromatography-photodiode array detector. Results : The higher pressure and longer extraction time increased the values of TSSC and extraction yield, while decreased the pH value. The decoctions produced in 180 min by pressurized method and produced in 150 min by non-pressurized method showed maximum values of extraction yield and TSSC with minimum value of pH. The amounts of chemical compounds showed variations in pressurized and non-pressurized decoction during overall extraction times. The influences of pressure and extraction time on extraction yield, TSSC, pH, and the contents of chemical compounds were confirmed by regression analysis, which showed that all extraction values were significantly affected by at least one of two extraction factors, pressure and extraction time. Conclusions : This study suggests that the pressure and extraction time can significantly affect the extraction efficiency of components from GBH decoctions. However, optimal extraction conditions could not be chosen due to the variation of the amounts of chemical compounds.