• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.229-232
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• 2000

The carbon dioxide, nitrogen, and phosphate removals from wastewater using microalgae have extensively been studied. Especially, the green colonial algae Botryococcus braunii is characterized by unusual high hydrocarbon contents, ranging from 15 to 75% of dry weight, as long-chain unsaturated hydrocarbons. These hydrocarbons suggest that the possibility of renewable biofuels to be converted into useful fuels such as gasoline by simple catalytic cracking. The poor recovery (18 - 32%) of hydrocarbon from B. braunii culture in two-phase bubble column seems to be caused by insufficient mixing between two phases, which was operated using only aeration on the narrow interface between hydrophobic solvent and cell suspension. In addition, hydrocarbon was entrapped tightly in cell-matrix (formed by exopolysaccharide) of algal colony, which make difficult to extract using two-phase system. In order to overcome low recovery efficiency, two-stage extraction culture system including culture vessel and two-phase separator is now under development, resulted improving contact between solvent phase and cell suspension. Hydrocarbon recovery using this process was more than two times as that using two-phase extraction culture.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.482-488
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• 2001

Platinum group metals (pgm) are useful to many industries such as chemical, dental and medical, petroleum, refining, electrical and electronic, and automotive. Researchers at the South Dakota School of Mines and Technology and PGM Recovery Ltd. have developed jointly an environmentally sound and metallurgically efficient process for extracting these metals from secondary sources. Once these metals have been dissolved in the leach liquor, the individual metals mainly platinum, palladium, and rhodium, should be separated in order to recover the individual metals with high purity. During this investigation, solvent extraction has been chosen as the method used to achieve the separation and extraction of platinum, palladium, and rhodium from the leach liquor. There were three solutions used throughout this procedure: 1) Synthetic solution (200 ppm Pt 80 ppm Pd 20 ppm Rh; 300 ppm Pt, 180 ppm Pd 50 ppm Rh), and 2) Auto catalyst leach liquors (100 ppm Pt, 30 ppm Pd, 20 ppm Rh). The solvents investigated included Lix 84(2-hydroxy-5-nonylacetonphenone oxime in a mixture with 5-dodecylsalicyloxime), Lix 84-I, ACORGA CLX-50 (diester of pyridine 3,5 dicarboxylic acid), and di-hexyl sulfide. The extraction values achieved using ACORGA CLX-50, Lix 84, and Lix 84-I were respectively Pt (25%, 0% 0%), Pd (100%, 99.8%, 95.3%), and Rh (99.1%, 35.5%, 4.25%). The stripping processes for the Lix 84, and Lix 84-I were proven to be more involved than others. The solutions were required to be simultaneously heated and stirred. The percentages acquired through these processes yielded unsatisfactory results. The stripping procedure for the ACORGA CLX-50 was easier to execute, yet the percentage recovered from this process was also unsatisfactory. Overall the di-hexyl sulfide has proved to be the most successful organic for this procedure. The average percent extracted for palladium was excellent with 99.9% - 100% with very little Platinum and rhodium extracted. The ability of stripping palladium in ammonia solution was also found to be excellent.

• Resources Recycling
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• v.9 no.2
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• pp.11-17
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• 2000

Consumption of nickel is continuously increasing and the wastes of secondary battery, ferrite and catalyst containing Ni are also generated periodically. Among those wastes, the aim of this research is the recovery of nickel from used Ni-Cd recharge battery. Battery consisted of Ni 24 wt%, Fe 30 wt% and Cd 18.5 wt%. Metal was recovered by solvent extraction after leaching. Cadmium was leached completely in 1N-HCl and Ni was recovered above 70%. 30 vol% MSP-8 separated Cd and Ni completely from acidic leaching solution. In addition $NH_4NO_3$ as one of ammonium salt type leachants showed an excellent leaching selectivity to Ni and Cd. Ni in leached solution was recovered completely by LIX-extractant and more than 70% of Cd in raffinate was by D2EHPA.

• Resources Recycling
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• v.32 no.1
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• pp.21-32
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• 2023

Because the application of lithium has gradually increased for the production of lithium ion batteries (LIBs), more research studies about recycling using solvent extraction (SX) should focus on Li⁺ recovery from the waste solution obtained after the removal of the valuable metals nickel, cobalt and manganese (NCM). The raffinate obtained after the removal of NCM metal contains lithium ions and other impurities such as Na ions. In this study, we optimized a selective SX system using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant and tri-n-butyl phosphate (TBP) as a modifier in kerosene for the recovery of lithium from a waste solution containing lithium and a high concentration of sodium (Li⁺ = 0.5 ~ 1 wt%, Na⁺ = 3 ~6.5 wt%). The extraction of lithium was tested in different solvent compositions and the most effective extraction occurred in the solution composed of 20% D2EHPA + 20% TBP + and 60% kerosene. In this SX system with added NaOH for saponification, more than 95% lithium was selectively extracted in four extraction steps using an organic to aqueous ratio of 5:1 and an equilibrium pH of 4 ~ 4.5. Additionally, most of the Na⁺ (92% by weight) remained in the raffinate. The extracted lithium is stripped using 8 wt% HCl to yield pure lithium chloride with negligible Na content. The lithium chloride is subsequently treated with high purity ammonium bicarbonate to afford lithium carbonate powder. Finally the lithium carbonate is washed with an adequate amount of water to remove trace amounts of sodium resulting in highly pure lithium carbonate powder (purity > 99.2%).

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.171-174
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• 2001

Solid phase micro-extraction (SPME), a solvent-free, rapid and inexpensive method for the extraction of organic compounds from aqueous sample matrices, was evaluated for determination of the 120 pesticides in vegetables such as crown daisy, perilla leaf, leafy lettuce and to mato. The analysis conditions were chosen for the SPME method: 15 min of immersion of the PDMS fiber in 10 ml of the solution with stirring at 1,000 rpm. The recovery tests were carried out in triplicate. The range of recoveries was 0-142% for organochlorine pesticides and $4.9\sim200\%$ for organophosphorus pesticides. The recoveries were very low in the pesticide groups with low solubility in water. The recoveries became lower in proportion to the interference materials in vegetables. The recovery in tomato was relatively higher than that in perilla Ie af and crown daisy. The recovery values obtained by SPE and SPME were compared. In leaf y lettuce, recovery obtained by SPE method ranged from $58.1\%\;to\;136.1\%$ and recovery by SPME ranged from $9.6\%\;to\;176.3\%$ In organophosphorus pesticides. The recovery in SPME method was satisfactory with $136\%$ for ethoprophos, $119\%$ for methidathion and $113\%$ for diazinon. Meanwhile, recovery of EPN, phenthoate and 2,4-DDT revealed relatively low value of $38\%,\;41\%\;and\;3.4\%,$ respectively. However, most of pesticides applied to SPME method sho wed constant recovery and precision. From these results, it can be concluded that solid phase micro-extraction might be an appropriate method for the screening test of pesticides in vegetables.

• Journal of Life Science
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• v.20 no.7
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• pp.999-1004
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• 2010

Investigations were carried out on a $\beta$-glucosidase produced by Aspergillus niger under solid-state fermentation conditions as a model of enzyme recovery from fermented wheat bran. The leaching efficiency of distilled water to recover the enzyme from the fermented bran was higher than acetate buffer, citrate buffer, citrate-phosphate buffer and 5% methanol; thus, the conditions were further optimized with distilled water as the extracting agent. After fermented bran was washed three times with distilled water for 1.5 hr each under shaking conditions at 1:5 solid to solvent ratio, a maximum recovery of 0.025 U/g of wheat bran was obtained.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.518-521
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• 2004

Ginseng saponin was isolated from panax ginseng root using high-speed countercurrent chromatography (HSCCC). Preliminary studies were performed to optimize physical properties of two-phase solvent system and operating parameters including rotation speed of column, elution mode of mobile phase, and flow rate. Two-phase solvent system for isolation of ginseng saponins was composed of chloroform, water, and methanol as blending solvent. Chloroform-aqueous methanol (4:6) systems with various concentration of methanol in water were evaluated for retention of stationary phase in column. Retention of stationary phase decreased with increasing flow rate in tail-to-head elution mode using upper phase as mobile phase and head-to-tail elution mode using lower phase as mobile phase. Latter mode produced high retention at flow rate of 5 mL/min. Optimum conditions for isolation of saponin were chloroform/methanol/water (40/39/21) solvent system; mobile phase, of lower organic layer, flow rate, of 5 mL/min, head to tail elution mode, rotation speed, of 800 rpm, and sample injection, of $200{\mu}L$, Recovery yield of ginseng saponin from panax ginseng root extract by HSCCC was 63.6%, and the purity of HSCCC fractions was verified by TLC.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.499-505
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• 2022

This study presents a conceptual design of vanillin production from Kraft lignin. Most of the existing Kraft lignin is used as low-quality boiler fuel or discarded as wastewater, and only 2% or less of lignin has been refined into high-quality products. We propose the process developed in this study to utilize discarded Kraft lignin. The existing vanillin production concept process consisted of alkali oxidation using NaOH, filtration, chromatography, and crystallization. Chromatography, which is difficult to commercialize, was changed to a solvent extraction process. The recovery rate of vanillin of the proposed solvent extraction process is 92.9%, and the purity is 99.5%, which is similar to the existing chromatography process. The reason why the solvent extraction process showing similar results to chromatography can replace the existing chromatography process was analyzed.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.47-53
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• 2018

Recovery of lactic acid from fermentation broth using chemical precipitation was investigated with various chemicals. Effects of chemical types, mixing speeds, settling duration, and solvent addition were evaluated to improve the recovery rates of lactic acid. Overall, recovery efficiencies increased as the dosage of chemicals increased. Recovery rate of lactic acid by CaO was higher than those of $Ca(OH)_2$ and $CaCO_3$. Recovery of lactic acid increased by 48% under the optimized reaction conditions which included a mixing speed at 180 rpm, a settling duration of 24 h, and addition of ethanol at 25%(v/v). Practical application needs to consider types and concentrations of other organic acids as well as lactic acid. Based upon the results of fluorescence excitation emission matrix (FEEM), size exclusion chromatography (SEC), characteristics of recovered lactic acid were same as that in the fermentation broth.

• Journal of Environmental Health Sciences
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• v.25 no.3
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• pp.103-107
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• 1999

Even if odorous compounds remain very low concentration in water, it cause strong odor. Because Geosmin and most of odorous compound had very low vaporization, those were difficult to analyze with GC/MSD and Purge & Trap. So, we needed pre-treatment method for decreasing amounts of extracting solvents, improving recovery efficiencies and increasing analytical efficiencies. This study developed efficient technology for analyzing odorous compounds, using various adsorbents and extracting solvents. The optimum adsorbent was XAD resins. Especially, XAD-2, XAD-7 and XAD-2010 were superior, but XAD-2 of these and the optimum extraction solvent is MTBE. Other extraction solvents' efficiency is in order of MTBE>Dichloromethane>n-Hexane>Diethylether. The optimum NaCl dosage for increasing efficiency is 5 g in liquid-liquid extraction method. The shaking time(0~24hr) has no concern with adsorption efficiency. The optimum adsorbent is XAD-2 resin and extraction solvent is MTBE. Dosing NaCl, adsorption efficiency is increased in liquid-liquid extraction method, but NaCl has no effect on liquid-solid extraction method. In this experimental results, this algae toxins(Mycrocystin, Anatoxin etc.).