• The Korean Journal of Food And Nutrition
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• v.34 no.2
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• pp.174-180
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• 2021

The purpose of this study was to determine the optimum extraction method suitable for the availability of biological activities in unripe apples known to be rich in functional components. Unripe apples 'Hongro' picked on May 28th, 2019 were extracted by various extraction methods (hot water, ethanol, enzymatic pre-treatment, ultrasonic wave, and subcritical water) and their extracts were investigated yield, effective component contents, and antioxidant activities. Overall, the yields by the extraction solvent were higher in water than in organic solvent(ethanol) because water-soluble compounds were eluted from a polar solvent. Total phenol contents of the ultrasonic wave (ethanol) extracts were significantly higher in 6 times than hot water extract. Contents of flavonoid were highest in the ethanol extract at 29.14 mg QE/g. Contents of tannin and ursolic acid were also significantly higher in the ultrasonic wave (ethanol) extract. The DPPH radical and ABTS radical scavenging activities were the strongest in the ultrasonic wave (ethanol) extract. Correlation between effective components and antioxidant activities was high in the total phenol content with ABTS and the ursolic acid content with DPPH (p<0.01). The above results suggested that ultrasonic wave (ethanol) extract of unripe apples has the potential to act as a functional material.

• Resources Recycling
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• v.7 no.5
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• pp.46-51
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• 1998

A study has been on the recovery of nitric acid and valuable metals such as Fe, Cu, Sn, Pb, from spent nitric etching solutions. The effects of extractant of extractant type, concentrations, phase raios and selectivity from Fe, Cu, Sn, Pb on nitric acid extraction were studied. The results showed that TBP as an extractant for recovering of nitric acid was more effective than Alamine336, and the optimal concentration of TBP was found to be 60~70% of organic phase. Also, the nitric acid were only extracted by TBP from the spent etching solutions and the heavy metals such as Fe, Cu, Sn, Pb were not extracted above 0.1N nitric acid in spent etching solutions, From the analysis of McCabe-Thiele diagram, the extraction of 95% nitric acid is attained at a ratio of O/A=3 with five stages by 60% TBP and the stripping of 98% nitric acid from 80 g/l nitric acid in organic phase is attained at a ratio of O/A=1 with four stages by distilled water.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.109-122
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• 2018

This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4 vol.% TOA, $2{\pm}0.1$ feed phase pH, 300 rpm stirring speed, at $40^{\circ}C$ with 0.2 (M) $Na_2SO_4$ solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85 kJ/mol) was found to be intermediate controlled and stripping (54.79 kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-${\grave{a}}$-vis extraction showed latter to be rate determining.

• Analytical Science and Technology
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• v.9 no.4
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• pp.336-344
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• 1996

The extraction of trace cobalt, copper, nickel, cadmium, lead and zinc in urine samples of organic and alkali metal matrix into chloroform by the complex with a dithizone was studied for graphite furnace AAS determination. Various experimental conditions such as the pretreatment of urine, the pH of sample solution, and dithizone concentration in a solvent were optimized for the effective extraction, and some essential conditions were also studied for the back-extraction and digestion as well. All organic materials in 100 mL urine were destructed by the digestion with conc. $HNO_3$ 30 mL and 30% $H_2O_2$ 50 mL. Here, $H_2O_2$ was added dropwise with each 5.0 mL, serially. Analytes were extracted into 15.0 mL chloroform of 0.1% dithizone from the digested urine at pH 8.0 by shaking for 90 minutes. The pH was adjusted with a commercial buffer solution. Among analytes, cadmium, lead and zinc were back-extracted to 10.00 mL of 0.2 M $HNO_3$ from the solvent for the determination, and after the organic solvent was evaporated, others were dissolved with $HNO_3-H_2O_2$ and diluted to 10.00 mL with a deionized water. Synthetic digested urines were used to obtain optimum conditions and to plot calibration-eurves. Average recoveries of 77 to 109% for each element were obtained in sample solutions in which given amounts of analytes were added, and detection limits were Cd 0.09, Pb 0.59, Zn 0.18, Co 0.24, Cu 1.3 and Ni 1.7 ng/mL, respectively. It was concluded that this method could be applied for the determination of heavy elements in urine samples without any interferences of organic materials and major alkaline elements.

• Resources Recycling
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• v.15 no.5 s.73
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• pp.3-10
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• 2006

The solvent extraction for the separation of platinum group metals from the leach liquor of spent automotive catalysts has been studied. Tri-n-butyl phosphate (TBP), tri-n-octylamine (TOA) and di-n-hexyl sulfide (DHS) were used as extractants and kerosene as a diluent. The extraction behavior of platinum, palladium and rhodium has been investigated as functions of different kinds of extractants and their concentrations. In addition, the extraction behavior of the major metal impurities such as cerium, lead, iron, magnesium and aluminum has been investigated. Platinum and palladium were extracted with TBP. And platinum, palladium and rhodium were extracted with TOA. Platinum was co-extracted with palladium into the organic phase by solvent extraction using SFI-6 of DHS extractant, but only palladium was selectively extracted with SFI-6R. The selective extraction of palladium with SFI-6R was found better than that with SFI-6, but the kinetics of extraction with SFI-6R was found poor in comparison to SFI-6. The metal impurities extracted simultaneously during the extraction of platinum group metals should be removed in scrubbing and stripping processes. A suitable process has been proposed for the separation of platinum group metals from the leach liquor of spent automotive catalysts. Initially palladium was extracted with SFI-6R, followed by the separation of platinum with TBP or TOA leaving rhodium in the raffinate.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.6
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• pp.814-824
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• 2005

This study analyzed and standardized the harmful substances of organic compounds(dioxins) in disposable diapers for infant's clothing. Commercial samples obtained from Korea, Japan, America and German were determined by HRGC/HRMS. Experimental Methods were consisted of comparision of extracting solvent, analysis of PCDD/Fs, and analysis of PCDD/Fs of extraction in disposable diaper. The results were as follows. No high TEQ values in TCDD(1), PCDD(0.5) and HxCDD(0.1) were found for commercial disposable diapers from country Korea, Japan, U.S.A and German. In extraction for 6hrs experiments, HpCDD and OCDD were detected in disposable diapers of U1, U2 and G2, respectively. In extraction fur 24hrs experiments, HpCDD, OCDD and OCDF were detected in disposable diapers of J3, U1, U2 and U3. So we need to set standards of measurement for harmful materials contained in textile goods. This will make a safe and comfortable clothing environment for all users, regardless of age.

• Journal of the Korean Chemical Society
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• v.30 no.4
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• pp.359-368
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• 1986

Solvent extraction equilibria of alkali metal cation with crown ether (DC18C6, DC24C8) and HDEHP have been studied. The extraction equilibrium constants increase in the order of, in the DC18C6 system, $Na^+, and in the DC24C8 system, $Rb^+. The species extracted to organic phase are $M_1(crown ether)_1\;(HDEHP)_1$. The magnitude of extraction equilibrium constant is determined by the distribution ratio of crown ether between organic and aqueous phase, and stability constant of crown ether-alkali metal complex.

• YAKHAK HOEJI
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• v.16 no.4
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• pp.180-185
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• 1972

A new spectrophotometric method was established for the determination of undecylenic acid. The method is based on the solvent extraction into nitrobenzene of the ion pair formed between tris(1,10-phenanthroline)Fe(II) chelate and the anion of undecylenic acid. The maximum absorbance of the extract in the organic phase was at 518nm. A maximum extraction was obtained at pH 9-11, when excess of at least 50-fold(molar) of the phenanthroline-Fe(II) chelate to undecylenic acid was present. The color intensity of the extracted species remained constant at room temperature for the several hours after separation of the organic layer. A linear relationship was obtained over the tested range of 5-20${\gamma}$/ml of undecylenic acid. The effect of several other fungicids on this method was investigated. The method was applied to the determination of undecylenic acid in preparations and the results were in good agreement with those added amounts.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.270-274
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• 2001

With Increasing importance of electroless nickel plating technology in many fields such as electronic and automobile industries, the treatment of the spent baths is becoming a serious problem. These spent baths contain iron and zinc as impurities, organic acids as complexing reagents, and phosphonate ions as oxidized species of tile reducing reagent. as well as several grams per liter of nickel. The spent baths are currently treated by conventional precipitation method. but a mettled with no sludge generation is desired. This work aims at establishing a recycling process of nickel from tile spent baths using solvent extraction. Extraction behaviors of nickel. iron. and zinc in various 쇼pes of real spent baths are investigated as a function of pH using LIX841, di (2-ethylhexyl)phosphoric acid (D2EHPA), and PC88A as tile extractants. Nickel is extracted by LIX84I at the equilibrium pH of more than 6 with high efficiency. For the weakly acid baths. iron and zinc are extracted by D2EHPA or PC88A without adjusting the pH of the baths leaving nickel in the aqueous phase. Stripping of nickel from LIX84I with sulfuric acid is also investigated. It is shown that concentrated nickel sulfate solution (> 100 ㎏-Ni/㎥) is obtained. This solution can be reused in the electroless plating process. Based on these findings, flow sheets for recovering nickel from the spent baths are proposed.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1036-1042
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• 1998

The preconcentration and determination of trace elements in water samples were studied by a solvent sublation utilizing dithizonate complexation. After metal dithizonates were formed, trace amounts of cadmium, cobalt, copper and lead were floated and extracted into small volume of a water-immiscible organic solvent on the surface of sample solution and determined in the solvent directly by GF-AAS. Several experimental conditions as formation condition of metal-dithizonate complexes, pH of solution, amount of dithizone, stirring time, the type and amount of surfactants, N2 bubbling rate and so on were optimized for the complete formation and effective flotation of the complexes. And also four kinds of light solvents were compared each other to extract the floated complexes, effectively. After the pH was adjusted to 4.0 with 5 M HNO3, 8.0 mL of 0.05% acetone solution of dithizone was added to 1.00 L water sample. The dithizonate complexes were flotated and extracted into the upper methyl isobutylketone (MIBK) layer by the addition of 2.0 mL 0.2% ethanolic sodium lauryl sulfate solution and with the aid of small nitrogen gas bubbles. And this solvent sublation method was applied to the analysis of real water samples and good results of more than 85% recoveries were obtained in spiked samples.