• Resources Recycling
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• v.11 no.6
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• pp.18-23
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• 2002

A study on the solvent extraction of hexavalent chromium from aqueous solutions has been investigated. The results showed that the extraction efficiency of chromium increased in proportion to extractant concentration. Aliquat 336 of quarternary amine effectively extracted hexavalent chromium and was superior to Alamine 336. And the stabilizers like polyhydric alcohols of octanol, decanol and dodecanol showed the similar effect fur prevention of third phase and a little promotion of extraction efficiency in comparison with non-use of polyhydric alcohols. On the other hand, in solvent extraction of hexavalent chromium from aqueous solutions, the hexavalent chromium was completely extracted at pH range lower than 7 with 1% Aliquat 336 as extractant and 5% decanol as stabilizer and the hexavalent chromium in extractant was completely stripped with 1M sodium hydroxide solution in the stripping step.

• Resources Recycling
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• v.11 no.6
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• pp.12-17
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• 2002

Solvent extraction experiments have been performed to separate copper from $CuCl_2$-$NiCl_2$-$CoCl_2$$ solutions using Alamine336 and LIX84. The complex formation tendency between metal ions and chloride ion had a great effect on the distribution coefficients of Cu, Co and Ni ions and separation factor of Cu to Co and Ni. In the experimental ranges of chloride ion concentration from 0.5 to 4.0 M, LIX84 was superior to Alamine336 in separating copper from cobalt. When the volume percentage of LIX84 and Alamine336 was varied from 5 to 40%, LIX84 was more effective than Alamine336 in separating Cu from Co and Ni in solutions in which the chloride ion concentration was 1.0 M.

• Resources Recycling
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• v.22 no.5
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• pp.29-34
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• 2013

Solvent extraction experiments were performed to separate platinum and rhodium from mixed chloride solution by using tri 2-ethylhexyl amine (TEHA) and its mixture with TBP and LIX 63. Effects of extraction conditions on the separation of the two metals were investigated as a function of extractant concentration in the HCl concentration range from 1 to 9 M. The concentration of Pt (IV) and Rh(III) was controlled to $1{\times}10^{-3}M$ and $2{\times}10^{-4}M$, respectively. In the extraction with TEHA and its mixture, Pt was quantitatively extracted irrespective of HCl concentration, while the extraction percentage of Rh depended on the extraction condition. When the concentration of HCl in the mixed solution was low, the extraction of Rh was nil and separation of Pt and Rh was possible. Adding TBP to TEHA had little effect on the extraction of both metals, while adding LIX63 to TEHA favored the extraction of Rh.

• Resources Recycling
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• v.26 no.3
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• pp.26-31
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• 2017

LIX 63 showed a selectivity for the extraction of Pd(II) over other PGMs, such as Pt(IV), Ir(IV) and Rh(III) from 6 M HCl solution. Moreover, HCl solution has significant effect on the oxidation-reduction reaction between Ir(IV) and LIX 63. Therefore, the applicability of employing LIX 63 for the separation of the 4 PGMs was investigated from 3 M HCl solution. From 3 M HCl solution, only Pd(II) was selectively extracted by LIX 63 and its extraction percentage was higher than from 6 M HCl solution. Extraction of the Pd(II) free raffinate with TBP led to the selective extraction of Pt(IV). After oxidation of Ir(III) with $NaClO_3$ to Ir(IV), extraction of the Pt(IV) free raffinate with Aliquat 336 selectively extracted Ir(IV). For each extraction step, optimum stripping conditions were obtained. By this process, it was possible to separate the 4 PGMs by solvent extraction from 3 M HCl solution.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.161-166
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• 2009

The purpose of the present study is to develop a simple, fast and sensitive LC/MS method for simultaneous separation and the determination of an active component in the oriental medicinal mushroom Cordyceps militaris. Based on this work, the contents of cordycepin in Cordyceps militaris fruiting cultivated on various media were determined and compared. And also, the nutritional components such as minerals and vitamins were determined in order to provide useful information to consumer as a food material. The analysis methods of nutritional components were chosen on the basis of AOAC. The optimum separation for cordycepin was achieved using a solvent gradient consisting of the mixture of 0.1% formic acid in methanol (solvent B) in a background of 0.1% formic acid in water (solvent A) as a mobile phase and a 3.0${\times}$150 Waters XTera column. Selective ion monitoring (SIR) mode ([M+H]+ at m/z 252) was used for quantitative analysis of cordycepin. The cultivated Cordyceps militaris on various media contained 1~14 /g of cordycepin, 0.65~1.08% of thiamine, 0.86~7.17% of riboflavin, and 3.01~5.26% of niacin. The content of mineral components varied on categories, especially contained 500~3500% of potassium as a major mineral. Cordycepin, niacin and potassium were found much higher in the fruiting cultivated with soy power media (gold 10) than other media.

• Resources Recycling
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• v.14 no.5 s.67
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• pp.18-23
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• 2005

Recovery of phosphoric acid from waste acid mixture of acetic, nitric and phosphoric acid has been attempted by using solvent extraction method. In this work, organic phosphate was used as an extraction agent. The effect of phosphate concentration, agitation speed and time on the solvent extraction of acetic and nitric acids has been investigated. The optimum concentration of phosphate for preferential extraction of acetic and nitric acids from waste acid was found to be about 50% irrespective of agitation speed and time. Purified phophoric acid was recovered from extraction residue at 1/3 of A/O ratio and 6th stage of extraction stage, which is well consistent with the value calculated by using McCabe-Thiele diagram.

• Resources Recycling
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• v.22 no.6
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• pp.19-25
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• 2013

Solvent extraction experiments have been conducted to separate Zr(IV) and Hf(IV) from chloride solutions by using LIX63 and Cyanex301. Zr and Hf were extracted by cation exchange reaction in the pH range from 1 to 4 by the extratants. Since the extraction percentage of the two metals was similar to each other, it was difficult to separate the two metals by using LIX63 or Cyanex301. Use of a mixture of LIX63/TBP or Cyanex301/TBP resulted in antagonism in our experimental ranges. Our data showed that there is some possibility of separating the two metals by the mixture of Cyanex301 and TBP because the extraction percentage of Hf decreased more rapidly than that of Zr as HCl concentration was decreased. The mixture of LIX63 and Cyanex301 had little effect on the separation of the two metals.

• Membrane Journal
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• v.15 no.1
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• pp.22-33
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• 2005

Asymmetric PVDF membranes were prepared by the phase inversion from casting solutions containing PVDF, NMP as solvent and 1,4-dioxane, DGDE, acetone, or GBL as additives by immersing them in water. The effects of various additives on the casting solution properties, permeation properties, and membrane structures were investigated. Low miscibility of 1,4-dioxane, DGDE and acetone with the coagulant (water) compared with NMP resulted in reducing the membrane pore size. When DGDE is used as an additive, the pore size was reduced because of its incipient sharp interface formation in the water. GBL increased membrane pore size because of its polarity compared to that of NMP. The PVDF membranes with various pore sizes could be obtained by controlling the amount of additive. The effect of mixed solvent (aqueous and non-aqueous solution) on permeation through membrane was investigated. Not only solution viscosity but surface tension affected solvent permeation.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.126-135
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• 2006

Phlorotannins which is oligomeric polyphenol of phloroglucinol unit were isolated from solvent fractions of methanolic extract of the brown alga, Ecklonia cava (EC). The inhibitory effects of phlorotannins from EC solvent fractions on oxidative stress were examined in human dermal fibroblasts (HDFs) related to wrinkle formation. Among the solvent fractions, phlorotannins from ethyl acetate fraction exerted the highest scavenging effect on DPPH radical, hydroxyl radical and alkyl radical analyzed by electron spin resonance (ESR) spectroscopy. The levels of intracellular reactive oxygen species (ROS) and lipid peroxidation were measured using 2',7'-dichlorofluorescin diacetate (DCFH-DA) and diphenyl-1-pyrenylphosphine (DPPP), respectively. Their levels were significantly decreased in the presence of phlorotannins from ethyl acetate fraction, compared with other fractions obtained from EC extract (P < 0.01). Furthermore, intracellular glutathione (GSH) level was significantly increased in a time dependent manner by the phlorotannins. Therefore, these results suggest that phlorotannins from EC extract could have a therapeutic potential for prevention and treatment of several diseases such as wrinkle formation related to oxidative stress.

• Macromolecular Research
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• v.17 no.3
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• pp.197-202
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• 2009

Solution-based, direct-write patterning by an automated, computer-controlled, inkjet technique is of particular interest in a wide variety of industrial fields. We report the construction of three-dimensional (3D), micro-patterned structures by polymer inkjet printing. A piezoelectric, drop-on-demand (DOD) inkjet printing system and a common polymer, PVA (poly(vinyl alcohol)), were explored for 3D construction. After a systematic preliminary study with different solvent systems, a mixture of water and DMSO was chosen as an appropriate solvent for PVA inks. The use of water as a single solvent resulted in frequent PVA clogging when the nozzles were undisturbed. Among the tested polymer ink compositions, the PVA inks in a water/DMSO mixture (4/1 v/v) with concentrations of 3 to 5 g/dL proved to be appropriate for piezoelectric DOD inkjet printing because they were well within the proper viscosity and surface tension range. When a dot was printed, the so-called 'coffee-ring effect' was significant, but its appearance was not prominent in line printing. The optimal polymer inkjet printing process was repeated slice after slice up to 200 times, which produced a well-defined, 3 D micro-patterned surface. The overall results implied that piezoelectric DOD polymer inkjet printing could be a powerful, solid-freeform, fabrication technology to create a controlled 3D architecture.