• 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.22 no.1
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• pp.11-19
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• 2013

Recovery of pure cobalt and nickel from diverse resources is important due to the increased demand for these metals. In order to get cobalt and nickel with high purity, separation of them from other metal ions is necessary. In this review, several methods to obtain pure cobalt or nickel solution, such as solvent extraction, ion exchange, precipitation were introduced and compared. For solvent extraction, the advantage and disadvantage of the separation process together with detailed process conditions were investigated.

• KSBB Journal
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• v.16 no.5
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• pp.442-445
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• 2001

Catechin compounds as anticancer and antioxidant were target materials from Korean Green Tea in this work. The methodologies of solvent extraction and partition were utilized to recover catechin compounds from green tea and the optimal experimental conditions were found by comparing the degree of recovery as slovent. extraction times and operating temperatures. The extract was partitioned with chloroform, which was best fit to remove caffeine after the extraction of green tea with 80$^{\circ}C$ water for 40 min. Further, the resulting extract was partitioned in ethyl acetate layer to purify the catechin compounds of EGC, EC EGCG and ECG. This experimental result could be extended to preparative HPLC to obtain EGCG on a commercial scale.

• Korean Journal of Human Ecology
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• v.21 no.5
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• pp.989-1004
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• 2012

The purpose of this study was to investigate the characteristics of the pigment and the dyeability of juniperus chinensis needles, berry, bark and heartwood extracts using distilled water, methanol, normal butanol and ethyl acetate as a solvent. Ultraviolet-visible absorption spectrum bands of the extracts were measured at around 280nm to 320nm in all the solvent extracts. The maximum absorption wavelength was able to determine tannin. All the solvent extracts except for distilled water extracts were able to confirm the presence of chlorophyll. Infrared absorption spectra (FT-IR) of all parts of the extracts showed broad absorption bands of OH due to phenolic-OH, benzene CH peak of phenol chemical structure, ether-based stretching vibration peak and the peak of flavonoid compounds that appeared in all the solvent extracts. The yield of juniper needles and heartwood in distilled water and methanol extraction were effective. Extraction of berry yields in distilled water was also effective. The yield of ethanol extraction from the bark showed better efficiency. As a result of using distilled water for the dye solution, the color of the fabrics dyed with all extracts of the needles and Y series berries generally showed light Y progression with a strong red tinge. By using a mixture of 20% ethanol and 80% distilled water for the dye solution, the color of the fabrics dyed with needles and berry extracts showed Y series dominantly. The color of the fabrics dyed with Bark and heartwood extracts were dominantly R series.

• Resources Recycling
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• v.12 no.1
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• pp.25-32
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• 2003

A study on the separation of heavy metals such as iron, copper, zinc and nickel from electroplating waste water has been investigated. The results showed that the PC-88A was more effective extractant for the extraction of zinc and the efficiency of zinc was to be about 100% at pH 2.5. And copper and nickel were extracted about 100% at pH 2 and more than 90% at pH 4～5 with LIX 84, respectively. On the other hand, in the case of solvent extraction of electroplating waste water(Acid-Alkali type) containing heavy metals, the ferric ion was first extracted at pH 2∼2.5 with 20% Naphthenic acid or 10% Versatic acid-10. And then, copper and zinc were extracted at pH 2 with 3% LIX 84 and at pH 2.5∼3 with 20% PC-88A respectively, remaining nickel in the raffinate. In this manner, the heavy metals in electroplating waste water could be effectively separated with solvent extraction method.

• 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.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.50-55
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• 2005

A comparison of alkali metal cation and alkaline earth cation solvent extraction was made for three additional monoionizable crown ethers and one diionizable crown ether. sym-(n-Octyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ exhibited high efficiency and selecvity in solvent extraction of alkali metal cations with respect to that observed with alkaline earth cations. Sizes of $Na^+$ and $Ca^{2+}$ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{3}$. As the result, $Na^+$ and $Ca^{2+}$ are the best extracted. sym-(n-Octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid $\underline{4}$was found to be somewhat selective for $Na^+$ over $Li^+$ and other alkaline earth metal cations. In the complexation of alklaine earth cations by crown ether diphosphonic acid $\underline{4}$, $Ca^{2+}$ and $Sr^{2+}$ are the appropriate sizes, but lager $Ba^{2+}$ may be due to favorable formation of a sandwich type complex between the crown ether cavity and the dianion of the deprotonated crown ether phoaphonic acid moiety.

• YAKHAK HOEJI
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• v.26 no.4
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• pp.223-229
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• 1982

Uremia is associated with defective protein binding of weakly acidic drugs, whereas the protein binding of basic drugs tends to be normal. The exact chemical nature of compound(s) and mechanism for these changes as yet is unknown, and has not been defined. Organic solvent extraction of pooled normal human urine following hydrolysis by hydrochloric acid produced an extract, which when added to normal human serum, was capable of inducing binding defects similar to those in uremia. Binding defects were observed with the weakly acidic drugs such as nafcillin, salicylate, sulfamethoxazole and phenytoin while the binding of the basic drugs such as trimethoprim and quinidine were unaffected. The binding defects induced by the hydrolyzed urine extract could readily be corrected by same organic solvent extraction of acidified serum and the defects could be transferred to the normal human serum using the organic solvent layer at the physiologic pH (7.4). Followed by reacidification ind extraction of the binding defects induced serum with the same solvent, separated several fractions were obtained on thin-layer chromatography. One of these fractions could reinduce the binding defects and this factor(s) is apparently weakly acidic compounds and tightly bound to serum at physiologic pH, but extractable at acidic pH, and its molecular weight range is approximately 500 or less similar to those seen in uremia. These findings strongly support the hypothesis that the drug binding defect in uremia is due to the accumulation of endogenous metabolic products which arc normally excreted by the kidneys but accumulate in renal failure.

• Resources Recycling
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• v.25 no.2
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• pp.33-41
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• 2016

A scale up tests (380 kg/day) using a continuous solvent extraction and electro-winning system was carried out to separate and recover cobalt from a solution containing 1.91 g/L Co and 14.65 g/L Ni. The solution was obtained during a process including solvent extraction and precipitation stages for removal of Cu and Fe from a synthetic sulfuric acid solution of manganese nodule matte. The optimal condition for solvent extraction was : solvent concentration of 0.22M Na-Cyanex 272 (45% saponified with NaOH) and O:A phase ratios of 1:1.5, 10:1 and 1.5:1 used in extraction, scrubbing and stripping stages, respectively. The extraction and stripping efficiencies were found to be 99.8% and 99.88%, respectively. The stripped solution contained 40.27 g/L Co with 4 ppm Ni. Cobalt metal of 99.963% purity was yielded with current efficiency of 67% and current density of $0.563A/dm^2$ during the electro-winning process.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.386-394
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• 2001

Carboxylic acids are examples of compounds with wide industrial applications and high potential, This article presents the principles of reactive extraction along with the character-istics of tertiary amine extractants, while is given on considering the effect of the amine class and chain length, As such a brief overview the current research on reactive extraction, including the recovery of citric acid, selective amine-based extraction , and extractive fermentation is given. When discussing extractive fermentation strategies for reducing solvent toxicity are also suggested based on specific examples. Finally, solvent regeneration and stripping of extracted acid explained.