• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.555-558
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• 2003

An enrichment/separation system for atomic absorption spectrometric determinations of Cu(Ⅱ), Fe(Ⅲ), Ni(Ⅱ) and Co(Ⅱ) has been established. The procedure is based on the adsorption of the analytes as calmagite chelates on Chromosorb-102. The effects of some parameters including pH, amount of ligand, salt matrix, flow rates of sample and eluent solutions were investigated. Under optimized conditions, the relative standard deviation of the combined method of sample treatment, preconcentration and determination with FAAS (N=5) is generally lower than 5%. The limit of detection (3σ) was between 6.0-112.9 ㎍/L. The results were used for preconcentration of analytes from some sodium and ammonium salt.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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• pp.322-328
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• 1993

A study of general characteristics of acetone extracted pigment from the cell mass of Rhodospirillum rusrum DSM 467 was carried out for the development of natural food colorant. Through visible absorption scanning, it showed seven absorption peaks at 355, 410, 529, 624, 680 and 747nm, and it was shown to be yellow color. In acidic and neutral conditions, the color was yellow, while in the alkaline condition it was greenish yellow. This pigment was stable at pH range between 3.0~10.0, and below 4$0^{\circ}C$. In the presence of light and oxygen, the stability of pigment rapidly degraded and it became unstable in the presence of metal ions such as Cu2+, Al3+ and Fe3+. Through TLC analysis, it was shown to be composed of seven color fractions.

• Membrane and Water Treatment
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• v.10 no.4
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• pp.299-305
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• 2019

Managed aquifer recharge (MAR) systems are gaining interest as an alternative to conventional water resources. However, when the water recovered in MAR systems, dissolved iron and manganese species may easily oxidize and they cause well screen clogging or require abandonment of extraction wells. In this study, both oxic and anoxic conditions were analyzed to verify the feasibility of the membrane filtration performance under various solution chemistries. The fouling mechanisms of the metal ions under anoxic conditions were also investigated by employing synthetic wastewater. The fouled membranes were then further analyzed to verify the major causes of inorganic fouling through SEM and XPS. The newly suggested anoxic process refining existing membrane process is expected to provide more precious information about nanofiltration (NF) membrane fouling, especially for demonstrating the potential advantages to chemical-free drinking water production for indirect potable reuse.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.141-146
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• 2007

The present paper describes a procedure for separation, preconcentration and determination of trace amount of copper in natural water samples by using 2-mercaptobenzimidazol as the complexing agent. The proposed method is based on the surfactant aggregation formed on γ-alumina by mixing sodium dodecyl sulfate and γ-alumina in water; 2-mercaptobenzimidazol was incorporated into inner hydrophobic part of produced ad-micelles in acidic media to produce an assemble suitable for preconcentration and determination of copper ion. Optimum experimental conditions for adsorption of μg/ml levels of copper ions from aqueous solution by the adsorbent have been reported. The copper ions were quantitively adsorbed by the sorbent over the pH range of 7.1-8.0 and were quantitatively desorbed afterward by using sulfosalycilic acid as the eluent. The determination of copper was not interfered in the presence of common metal ions. The procedure was applied for analysis of river water sample. Relative standard deviation was found to be 4.91%.

• Resources Recycling
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• v.31 no.1
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• pp.12-20
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• 2022

The smelting reduction of spent lithium-ion batteries results in metallic alloys containing Co, Cu, Fe, Mn, Ni, and Si. A process to separate metal ions from the sulfuric acid leaching solution of these metallic alloys has been reported. In this process, ionic liquids are employed to separate Fe(III) and Cu(II). In this study, D2EHPA and Cyanex 301 were employed to replace these ionic liquids. Fe(III) and Cu(II) from the sulfate solution were sequentially extracted using 0.5 M D2EHPA with three stages of cross-current and 0.3 M Cyanex 301. The stripping of Fe(III) and Cu(II) from the loaded phases was performed using 50% (v/v) and 60% (v/v) aqua regia solutions, respectively. The mass balance results from this process indicated that the recovery and purity percentages of the metals were greater than 99%.

• Journal of the Korean Chemical Society
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• v.32 no.5
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• pp.443-451
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• 1988

New crown ether dye-Ⅰ and dye-Ⅱ having an azo group(-N=N-) were synthesized from monobenzo-15-crown-5 and dibenzo-18-crown-6. These dyes showed ${\lambda}_{max}$ of 377 and 383nm respectively. The complexes of alkali metal ions ($Na^+$, $K^+$, $Cs^+$) with dye ligands showed band shift (390~400nm) and intensity increased. For a given anion, the extraction constants are in the order of $K^+$ < $Cs^+$ < $Na^+$ for dye-Ⅰ and $Cs^+$ < $Na^+$ < $K^+$ for dye-Ⅱ. These results show that the selectivity of crown ethers toward the alkali metal ions is dependant on the charge density of cation and the size of crown ether cavity. For a given cation, the order of the extraction constant is $Cl^-$ < $Br^-$ < $I^-$ < picrate. This order coincides with the degree of anion solvation effect.

• Analytical Science and Technology
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• v.11 no.4
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• pp.281-291
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• 1998

An analytical method for the simultaneous measurement of trace Cu, Sn, and Bi in blood and urine has been investigated by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Microwave oven was used for the pretreatment of blood samples using nitric acid and hydrogen peroxide in a closedvessel digestion system with 1 mL whole blood for 8 minutes. Amberlite IRC-718 resin was used as a solid phase in solid-liquid extraction technique for the removal of matrix interferences such as Na, S, P, and other polyatomic ion species. Detection limits for Cu, Sn, and Bi by this method were 0.000375 ng/mL, 0.000297 ng/mL, and 0.000174 ng/mL, respectively. Recoveries of 99.1% for Cu, 102.5% for Sn, and 98.4% for Bi were obtained for the standard spiked NIST SRM 955a blood sample. The developed method was applied for whole real blood and urine samples.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.31-39
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• 2015

The synergistic solvent extraction of rare earth elements such as europium and yttrium has been investigated by the extractant with crown ether as an additive. Macrocyclic ligand as host-guest compounds form more stable complexes with metal ions which have the similar size of the cavity of crown ether. In our previous study[14] founded that the extraction used fatty acid of the various alkyl chain length. Based on the results of the previous experiment, the synergistic separation effect of two metals investigated that the hexanoic acid had was the worst extraction effect which added a crown ether such as 18-crown-6 ether, 15-crown-5 ether, and 12-crown-4 ether. In this study, the concentrations of hexanoic acid have showed the separation effect, and then the concentrations and kind of crown ether are performed for synergistic extraction at the hexanoic acid concentration of the highest separation effect. As a results, the separation rate is the highest value of 1.72 at 0.05 M hexanoic acid, and 0.002M 15-crown-5 ether is the best value in other concentrations and kind of crown ether, it is about twice of using only hexanoic acid. Moreover, the extraction species of two metals has been founded $MLR_3{\cdot}3RH$ form when added the crown ether.

• Journal of the Korean Chemical Society
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• v.19 no.6
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• pp.428-433
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• 1975

500 ml of a sample water was extracted with 10 ml of 0.01 % dithizone-$CHCl_3$three times. When $CHCl_3$ layer was back extracted with 10 ml of 0.1 N HCl containing mercuric ion, the free metal ions come into aqueous layer. The aqueous layer was added with 2 ml of 2 N KCl and was washed with 10 ㎖ of $CHCl_3$two times in order to remove the trace dithizone, and then was recorded square wave polarogram. The concentration of copper, lead and cadmium can be determined up to 3 ppb and that of zinc up to 14 ppb with an error of 10 %.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.125-129
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• 1994

The acetone extracted pigment from the cell mass of Rhodophila globiformis DSM 161 was generally red. In a pH 5-6 condition, the color of pigment was red, while in p/h 7-9 condition it was yellowish red. The pigment was stable at pH range between 6.0-11.0 and below 4$0^{\circ}C$. In the presence of light and oxygen , the pigment was rapidly degraded and became unstable in the presence of metal ions such as Fe3++(1.0$\times$ 10-2M, 1.0$\times$10-3 M), Al3+ (1.0$\times$10-2 M, 1.0$\times$10-3 M) and Zn2+(1.0$\times$10-2 M). But in the presence of Zn2+ (1.0$\times$10-2M). But in the presence of Zn2+ (1.0$\times$10-3 M) it was very stable. Through visible absorption scanning ,it showed five sharp absorption peaks at 358 , 385, 494, 680 ad 748 nm with three shoulder peaks at 410, 466 and 522nm. On the results of TLC analysis , it was shown to be composed of seven color fractions.