• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.303-308
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• 2017

The $FeCl_3$ waste solution used to etch various metals contains valuable metal such as nickel. In this study, we recovered as high purity nickel carbonate crystalline powders from nickel-containing etching waste solution after regeneration of iron chloride. Firstly we eliminated about of the iron impurities under the condition of pH 4 using 5 % NaOH aqueous solution and then removed the remaining impurities such as Ca, Mn and Zn etc. by using solvent extractant D2EHPA (Di-(2-ethylhexyl) phosphoric acid). Thereafter, nickel carbonate powder having a purity of 99.9 % or more was obtained through reaction with sodium carbonate in a nickel chloride solution.

• Membrane and Water Treatment
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• v.7 no.6
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• pp.521-537
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• 2016

Laboratory-scale experiments were carried out to investigate the adsorption equilibrium, the adsorption kinetics and facilitated transport of two cationic dyes (Methylene Blue (MB) and Rhodamine B (RB)) on Polymer Inclusion Membrane (D2EHPA-PIM). Different adsorption isotherms (Freundlich, Langmuir and Temkin models) as well as kinetics models indicated that the adsorption process is spontaneous and exothermic. Under the optimal conditions, the adsorption removal efficiencies reach about 93% and 97% for MB and RB respectively. Different extraction values by D2EHPA-PIM were obtained for the two cationic dyes: MB is weakly extracted at pH 2.0 (E% = 18.7%) whilst E% = 82.4% was observed for RB at the same pH. This difference was exploited in a mixture containg both the 2 cationic dyes for the selective extraction of RB at pH 2. Desorption of both dyes was achieved from the membrane by using acidic aqueous solutions and desorption ratio up to 90% was obtained. The formulas of the extracted complexes by the PIMs were, determined by the method of slopes. The dyes transport was elucidated using mass transfer analysis where in it found relatively high values of the initial flux ($J_0$) as 41.57 and $18.74{\mu}mol.m^2.s^{-1}$ for MB and RB respectively.

• 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.25 no.2
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• pp.3-9
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• 2016

Separation of Zr(IV) and Hf(IV) from sulfuric acid solutions was investigated by extraction with several acidic extractants such as Versatic acid, LIX 63, and Cyanex 301. From strong sulfuric acid solutions, the separation of Zr(IV) and Hf(IV) by Versatic acid and LIX 63 was not possible, while selective extraction of Hf(IV) over Zr(IV) was obtained with Cyanex 301. However, the extraction percentage of the two metals was much lower compared to that by D2EHPA. Mixing of TBP with Cyanex 301 and D2EHPA led to negative effect on the extraction and separation of the two metal ions. The difference in the extraction reaction and separation selectivity between HCl, $HNO_3$ and $H_2SO_4$ media with each extractant was discussed.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1053-1060
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• 1996

$\beta$-ketohexanal as a chelating extractant was synthesized from the reaction of ethyl formate and methyl propyl ketone in the presence of sodium amide, and the equilibrium characteristics in the extraction of copper by $\beta$-ketohexanal-chloroform were investigated. The equilibrium constants such as the dissociation constant and the partition coefficients of $\beta$-ketohexanal, the stability constant and the partition coefficient of copper chelating complex, and the overall equilibrium constant in the extraction of copper were determined by spectrophotometric measurements, and the mechanism of extraction was proposed. The percent of extracted copper by $\beta$-ketohexanal-chloroform was near 100%, and the selective extraction of copper from Cu-Zn-Cd mixture was possible. Copper was found to be extracted as $CuR_2$ and the equilibrium reaction was expressed as $Cu^{2+}+2{\overline{HR}}{\rightleftarrows}{\overline{CuR{_2}}}+2H^+$.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1747-1754
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• 2008

Acidithiobaeillus ferrooxidans ATCC 23270 is an important model organism for bioleaching and bioremediation studies owing to its diverse metabolic capabilities, whereas lix984n is a widely used extractant. Little is known about the response of cbb genes in A. ferrooxidans to lix984n shock. Thus, to elucidate the response of the $CO_2$ fixation genes in A. ferrooxidans ATCC 23270 to the addition of lix984n, the gene expression of cbb genes was examined using a real-time PCR. Although a natural increase or decrease in the expression of most cbb genes was observed after 5 min of shock with 3% (v/v) lix984n, sdhC and cbbR exhibited quick responses to the shock. Ten min of shock had a greater effect on the cbb gene expression, yet 15 min of shock had a significant effect on the Calvin cycle in A. ferrooxidans ATCC 23270, as the expression of all the cbb genes reached a very high level. Therefore, after a short lix984n shock, a solution of A. ferrooxidans can be re-used for bioleaching.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.418-422
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• 1999

A method is described for the selective determination of Cr(III) and Cr(VI) in aqueous solutios by flame atomic absorption spectrometry. Selective extraction of $Cr_2O_7^{2-}$ was performed by Aliquat 336/NIBK from the mixtures of $Cr^{3+}$ and $Cr_2O_7^{2-}$, and the extraction of $Cr^{3+}$ was followed after complex formation with citrate by using the same extractant. The concentraction of each analyte in the extract was determined by $N_2O-C_2H_2$ flame atomic absorption spectrometry. The recoveries of $Cr^{3+}$ and $Cr_2O_7^{2-}$ from 50mL of aqueous solution ranging 0.1~1.0 ${\mu}g/mL$ as Cr respectively by single extractions with 5 mL of 1%(V/V) Aliquat 336/MIBK were resulted as 98.8∼101.7%.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.687-693
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• 2018

The selective removal and recovery of fermentation inhibitors during purification of sugars from biomass hydrolysates can increase the economic efficiency of the entire process to produce bioalcohol from lignocellulosic biomass. This study investigated the effect of furans in phenols-free biomass hydrolysate on acetic acid extraction in an emulsion liquid membrane system. Under specific operating conditions, more than 99% of acetic acid could be extracted within 5 minutes, and the degrees of extraction of furfural and 5-hydroxymethylfurfural were about 10% and 4%, respectively. The extraction rate of acetic acid was also lower at a higher initial concentration of furfural in the feed phase, which was greater for furfural than 5-hydroxymethylfurfural. Thus, if furfural is first removed from the hydrolysate prior to acetic acid extraction, emulsion liquid membrane would be a more economically efficient way of removing acetic acid.

• 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.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.457-462
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• 2015

Hemicellulosic hydrolysates contain not only sugars but also several kinds of ethanol fermentation inhibitory substances such as carboxylic acids, furans and phenolic compounds. In this work, emulsion liquid membrane (ELM) was chosen as a separation technology to remove the inhibitors. A basic simulated hemicellulosic hydrolysate was composed of xylose as sugar, dilute sulfuric acid solution as solvent, and acetic acid as carboxylic acid, and furfural as furan derivative or p-hydroxybenzoic acid(HBA) as phenolic compound was added to the hydrolysate when necessary. Acetic acid and HBA as weak acid could be selectively removed from the hydrolysates in all the ELM systems considered here, but furfural as aldehyde was quite hard to remove. Also, when HBA was added to the basic simulated hemicellulosic hydrolysate, both of acetic acid and HBA in the feed phase could be selectively removed up to 99% in an ELM system with tributyl phosphate as extractant.