• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.238-243
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• 2012

Laminaria roots have not been practically used in Korea. In this study, the extraction process of carbohydrates and minerals from Laminaria roots was investigated and the properties of extracted components were measured. Hydrochloric acid generally used in carbohydrate extraction from seaweeds in order to obtain high extraction yield. But in this work, to utilize extracted components as a functional food material, organic acids such as citric acid were used. Organic acid as extraction solvent has low extraction yield compared to strong acids. Therefore optimum condition for maximum yield was investigated in carbohydrate extraction from Laminaria roots using organic acid. We measured the extraction yields of carbohydrate with variation of extraction temperature, extraction time, concentration of organic acid and particle size of samples. The extraction yield increased as the particle size decreased and temperature became high. The extraction yield was 19.0 wt% after 4.0 hours extraction with 0.2 wt% citric acid at $100^{\circ}C$. Potassium concentration was high compared other minerals in extraction solution, that is, the ratio of K/Na was about 3.0. Fucoidan from Laminaria roots had same carbohydrate composition and lower molecular weight compared that of Undaria pinnatifida.

• Resources Recycling
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• v.19 no.3
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• pp.45-51
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• 2010

Solvent extraction behavior of Sn(IV) from hydrochloric acid solution was investigated using TBP(Tri-butyl Phosphate) as an extractant. The experimental parameters, such as the concentration of HCl solution, chloride ions, extractant, and Sn were observed. Experimental results showed that the extraction percent of Sn was increased with increasing the hydrochloric acid and chloride ion concentration. More than 98% of Sn was extracted in 7.0 M HCl by 10% TBP. The optimum extraction stages of Sn for continuous extraction process was theoretically calculated by analysizing the McCabe-Thiele diagram. Stripping of Sn from the loaded organic phases can be accomplished by NaOH as a stripping reagent effectively and 99.3% of Sn was stripped by 2.0M NaOH solution.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.631-639
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• 2015

Extraction/separation of cobalt by solvent extraction is reviewed. Separation of cobalt using various reagents and also cobalt recovery from scrap using commercial extractant were analyzed. The separation ability for cobalt followed the order of phosphinic > phosphonic > phosphoric acid due to the increasing stabilization of tetrahedral coordination of cobalt complexes with the extractant in the organic phase. Depending upon the solution composition, commercial extractants like Cyanex 272, D2EPHA and PC 88A should primarily be used for commercial extraction processes and also the efficient management of their combination could address various separation issues associated with cobalt bearing scrap.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.320-325
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• 1978

In order to elucidate the mechanism associated with the solvent extraction of uranium(VI) using DEPA and DPPA as extractant the uranium(VI) complexes formed during the solvent extraction were isolated and characterized by means of IR, NMR, chemical analysis and molecular weight determination. It has been found that uranium(VI) replaces the acidic hydrogen ions of the extractants DEPA and DPPA to form chelated polynuclear complexes, the molecular weight of U(VI)-DEPA complex being $2.1{\times}10^4$. The isolated U(VI)-DEPA complex has been found to be the same chemical species as is formed during the solvent extraction process. In case of DEPA the distribution coefficient of uranium is the largest of the pure aqueous uranium solution and is increasing for the acidic solutions in the order of $H_3PO_4.

• Journal of Environmental Science International
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• v.23 no.1
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• pp.89-96
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• 2014

Styela clava tunic is generated in large amounts as a waste from S. clava processing plants and causes environmental problem. Although biological activities of S. clava were reported by many investigators, study on S. clava tunic was little. In this study, therefore, tyrosinase inhibition and antioxidative activities of extracts from S. clava tunic using different solvent were investigated for recycling of the fishery waste. Among extraction methods tested, autoclaved extraction (25.7%) and hot water extraction (18.2%) appeared to be effective for extraction. The highest total phenolic content was 46.6 mg/g in autoclaved extract while the highest flavonoid content was 23.0 mg/g in chloroform extract. All extracts possessed tyrosinase inhibition activity and the inhibition activity was concentration-dependent. Inhibition concentration ($IC_{50}$) against tyrosinase activity was $0.36{\times}10^4$ mg/ml in ethanol extract, $0.11{\times}10^3$ mg/ml in acetone extract and 0.27 mg/ml in n-butanol extract. Among extracts tested, hot water and autoclaved extracts displayed higher antioxidative activity than organic solvent extracts. Therefore, our data suggest that extract from S. clava tunic may potential candidate for cosmetic product with whitening effect and medicine for diseases caused by various oxidative stresses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.438-445
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• 2017

Tanzania has abundant copper deposits, but copper-metal extraction remains low there, owing to the lack of suitable copper recovery processes and insufficient funds for developing mining technologies. Accordingly, leaching and solvent extraction methods for the extraction of copper from copper ore were studied with a particular emphasis on developing a simple processing method for small-scale copper mining. Chrysocolla ore was used as the copper-bearing mineral and sulfuric acid was used as the leaching reagent. A maximum copper recovery of 95.1% was obtained when the particles in the sample were smaller than $53{\mu}m$, the concentration of 98%(w/w) sulfuric acid in the leaching solution was 5.0 g/L and the stirring rate was between 60 and 80 rpm. The highest selectivity of $Cu^2+$ in the solvent extraction was obtained using 15% LIX-70 in kerosene. In the pH range from 0.5 to 3.0, the efficiency of $Cu^2+$ extraction increased with increasing pH. However, at pH values higher than 3.0, other metal ions were extracted into the organic phase more readily than $Cu^2+$. The highest solvent extraction rate obtained was 96.5% at pH values of 2.0 and 3.0 using 15% LIX-70.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.719-724
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• 2001

The objective of this investigation was to separate silicon and silica for recycling by the liquid-liquid separation technique. In the preparation of silicon (Si) single crystal, a small amount of silicon is fixed on the surface of silica (quartz, $SiO_2$) crucible. The used crucible is crushed for recycling both silicon and silica in a high purity from the mixed powder. Zeta-potential of silicon and silica are almost the same at pH higher than 3. Their separation by simple flotation is ruled out. However, their hydrophobic characteristics are different in several different organic solvent from the measurement of contact angle. Therefore, the liquid-liquid extraction is employed to separate silicon and silica. The result indicates that the organic solvent mixed with dodecyl ammonium acetate could extracted the silicon powder at high purity (97-100%) with high recovery from the silica powder in the water phase.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1996-2000
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• 2005

Headspace hanging drop liquid phase micro-extraction (HS-HD-LPME) is studied as a novel solvent-based sample pretreatment method for floral volatile aroma compounds. This paper reports on application of the HSHD- LPME combined with GC-MS for the analysis of linalool component emitted from evening primrose flowers. The effect of several variables on the method performance was investigated. Additionally, the separation of enantiomers on a cyclodextrin capillary column was performed to identify chirality of (−)-linalool component. Since the unsurpassed volume of a few micro-liters of solvent is used, there is minimal waste or exposure to toxic organic solvents. This method enables to combine extraction, enrichment, clean-up, and sample introduction into a single step prior to the chromatographic process.

• Nuclear Engineering and Technology
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• v.14 no.3
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• pp.110-115
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• 1982

The mechanism of the suppression effect of the extraction of microquantities of an element in the presence of microquantities of another element in some solvent extraction systems is considered. For the system of metal halide complex acids, it has been revealed that the principal cause of the suppression phenomenon is due to the dissociation of the compounds extracted into the organic phase. The various factors, such as relative value of distribution ratios of the individual micro and macroelements, stability of halide complex anion are discussed, and a equation relating those factors are derived.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.35-42
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• 2009

Headspace micro solid phase extraction using mulberry paper bag (HS-MPB-$\mu$-SPE) has been developed and validated for the analysis of volatile flavor compounds from five spice by gas chromatography-mass spectrometry (GC/MS). HS-MPB-$\mu$-SPE was performed with adsorbent particles enclosed inside a mulberry paper bag. Four different kinds of adsorbents such as Tenax TA, Porapack Q, dimethylpolysiloxane and polyethylene glycol were tested. The extraction solvents compared were petroleum ether, methylene chloride, and chloroform. Better results were obtained when Tenax TA and petroleum ether were used. The limit of detection (LOD) and the limit of quantitation (LOQ) were in the range of 1.3 ng/mL and 4.3 ng/mL, respectively, for o-cymene as a model compound of monoterpene. Proposed method showed good reproducibility (3.3%, RSD) and good recoveries (94.0%). The HS-MPB- μ-SPE is very simple to use, inexpensive, rapid, requires small sample amounts and solvent consumption. Because the solvent for extraction is reduced to only a very small volume (0.6 mL), there is minimal waste or exposure to toxic organic solvent and no further concentration step. This method allows successful characterization of the headspace in contact with the five spice sample. Strong trans-anethole from star anise or fennel is a characteristic flavor of five spice powders. HS-MPB-$\mu$-SPE combined with GC/MS can be a promising technique for the broad spectrum measurement of volatile aroma compounds from solid spices.