• Journal of Environmental Science International
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• v.8 no.3
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• pp.411-417
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• 1999

The interfacial chemical behavior, lattice exchange and dissolution, of $FeS_{(S)}$ as one of the important sulfide minerals was studied. Emphases were made on the surface characterization of hydrous $FeS_{(S)}$, the lattice exchange of Cu(II) and $FeS_{(S)}$, and its effect on the dissolution of $FeS_{(S)}$, and also affect some organic ligands on that of both Cu(II) and $FeS_{(S)}$. Cu(II) which has lower sulfide solubility in water than $FeS_{(S)}$ undergoes the lattice exchange reaction when Cu(II) ion contacts $FeS_{(S)}$ in the aqueous phase. For heavy metals which have higher sulfide solubilities in water than $FeS_{(S)}$, these metal ions were adsorbed on the surface of $FeS_{(S)}$. Such a reaction was interpreted by the solid solution formation theory. Phthalic acid(a weak chelate agent) and EDTA(a strong chelate agent) were used to demonstrate the effect of organic lignads on the lattice exchange reaction between Cu(II) and $FeS_{(S)}$. The $pH_{zpc}$ of $FeS_{(S)}$ is 7 and the effect of ionic strength is not showed. It can be expected that phthalic acid has little effect on the lattice exchange reaction between Cu(II) and $FeS_{(S)}$. whereas EDTA has very decreased the removal of Cu(II) and $FeS_{(S)}$. This study shows that stability of sulfide sediments was predicted by its solubility. The pH control of the alkaline-neutralization process to treat heavy metal in wastewater treatment process did not needed. Thereby, it was regarded as an optimal process which could apply to examine a long term stability of marshland closely in the treatment of heavy metal in wastewater released from a disussed mine.

• Korean Journal of Microbiology
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• v.23 no.1
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• pp.25-33
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• 1985

The cell-free cellulolytic enzyme was separated into 3 different enzyme proteins by gel-filtration and ion-exchange chromatography. These fractions were named enzyme A, enzyme B and enzyme C. The mode of action of each of the separated enzymes on crystalline cellulose was examined using infrared spectroscopy and X-ray crystallography. It was concluded that enzyme B is of the $C_1-type$ and reduces the crystallinity of the subatrate by generation an unstable glucopyranose ring structure, whilst enzymes A and C are of the $C_x-type$ and hydrolyse the reaction product of enzyme B to constituent sugars. A reaction scheme for this cellulase system is proposed and discussed.

• Macromolecular Research
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• v.12 no.4
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• pp.407-412
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• 2004

A new hydroxyl group-containing conjugated ionic polymer, poly[2-ethynyl-N-(p-hydroxyphenylethyl)pyridinium bromide], was synthesized by the activated polymerization of 2-ethynylpyridine with p-(2-bromoethyl) phenol without any additional initiator or catalyst. The polymerization proceeded well to give a moderate yield (65%) of polymer at a reaction temparature of 90$^{\circ}C$. Another polymer, poly[2-ethynyl-N-(p-hydroxyphenylethyl)pyridinium tetraphenylborate], was readily prepared by the ion-exchange reaction of poly[2-ethynyl-N-(p-hydroxyphenylethyl)pyridinium bromide] with sodium tetraphenylborate. These polymers were completely soluble in organic solvents such as DMF, DMSO, and acetone, but insoluble in water and ether. Instrumental analyses, such as NMR, IR, and UV-Vis spectroscopies, indicated that the new materials have conjugated polymer backbone systems with the designed substituents and counter anions. X-Ray diffraction analyses of the polymers indicated that they were mostly amorphous.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.731-736
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• 2010

In this study, the sulfonated SBS cation-exchange membrane was prepared by post-sulfonation. Degree of sulfonation(DS), water-uptake, ion exchange capacity and electrical resistance and conductivity of sulfonated SBS were investigated as a function of sulfonation time. The DS of sulfonated SBS membrane was increased with increasing the reaction time and concentration of sulfuric acid. The maximum value of DS was 24.0%. And also, the water uptake and ion exchange capacity of the sulfonated SBS membrane were increased as increasing the value of DS. The values of water uptake and IEC were 41.2% and 0.80 meq/g, respectively. The electrical resistance and conductivity of the membrane showed $23.6{\Omega}{\cdot}cm^2$ and $4.24{\times}10^{-4}S/cm$, respectively.

• Journal of the Korean Chemical Society
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• v.4 no.1
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• pp.62-66
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• 1957

With the intention of preparing cation exchangers from the domestic coals, and using these for softening hard water and some other purposes, seven kinds of raw coal were tested and the results are as follows. 1) The following conditions of preparation were given the good results. Reaction time 5 hours Reaction temperature $95^{\circ}$ Concentration of sulfuric acid 98% Amount of sulfuric acid 10 times to the sample (as weight) 2) The raw coals which is rich in fixed carbon and have the fuel ratio 0.8 to 1.0 were suitable, and Kampo lignite has shown the best results. 3) The cation exchangers from coals were able to exchange the cation, both hydrogen and sodium type dynamically and statically, like the synthetic ion exchange resin. The exchange capacities were as follows. Total capacity 1.60 meq/g. Breakthrough capacity 1.30 meq/g. Usable breakthrough capacity 1.20 meq/g National Central Research laboratory

• Nuclear Engineering and Technology
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• v.23 no.4
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• pp.420-425
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• 1991

The Rb charge exchange cell is constructed as the He- ion source of the SNU 1.5- MV Tandem Van do Graaff accelerator. The characteristic experiment is carried out in order to determine the optimum operational conditions of the cell. The $He^{+}$ ion beam with the energy of 1~10 keV, extracted from the duoplasmatron ion source, is passed through the Rb vapor to become He- ions by the two step charge exchange reaction, i.e., $He^{+}\;+\;Rb\;{\rightarrow}\;He^{\circ\ast}\;+\;Rb^{+}\;and\;He^{\circ\ast}\;+\;Rb\;{\rightarrow}\;He^{-}\;+\;Rb^{+}$. From the experimental results, it is found that the maximum fractional yield of $He^{-}$ ions is produced at He+ ion energy of 7 keV. The optimum temperatures of the oven and the canal are determined to be $370\;^{\circ}C{\;}and{\;}95^{\circ}C$ respectively. Under the optimum operational condition the maximum fractional yield of $He^{-}$ ions is $2.42\pm0.02%$ This charge exchange cell is proved to be an effective system for the production of He- ions.

• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.115-120
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• 1969

Kinetics of reactions of halide ions with 1-naphthyl methyl halide have been investigated in anhydrous acetone. Semi-quantitative analysis of the results shows that if the softness of the substrate increases remarkably, the nucleophilicity order of halide ions is $I^- > Br^- > Cl^-$ even in dipolar aprotic solvent. But for 1-naphthyl methyl bromide, though the reaction center which was made soft by symbiosis of bromine atom raises the reactivity of soft nucleophile, nucleophilicity order indicates that soft-soft interaction is interfered by perihydrogen.

• Membrane Journal
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• v.12 no.1
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• pp.51-53
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• 2002

The hydrogen ions in poly (vinyl alcohol) (PVA)/sulfosuccinic acid (SSA) membranes substiuted with $Li^+, Na^+, and K^+/ $of monvoalent metal ions, $Mg^{2+}, Ca^{2+} and Ba^{2+}$ of divalent metal ions, and $Al^{3+}$ of trivalent metal ion. In addition, $Li^+ ions were exchanged with varing reaction time. The effects of metal ions exchanged were investigated in terms of methanol permeability -uling diffusion cell. The methanol permeabilies decreased in the sequence of $Na^+, Li^+ and K^+$ and this might be due to the 'Salting-out' effect while the methanol permeabilities for divalent and trivalent ion-substituted membranes were affected by the combined effects of salting-out, eletrostatic crosslinking and extent of metal ion substiution. As for $Li^+$ ions, methanol permeabilities of PVA/SSA membranes decreased in proportion to the degrees of subsituted $Li^+$ ions.

• Journal of Environmental Science International
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• v.10 no.6
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• pp.387-391
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• 2001

The hydroxyapatite(HAp) as a carrier the for ion exchange agent of $Ag^+$ions was prepared in semiconductor fabrication, The Ca/P molar ratio of the HAp was 1.65. The HAp is molded in shape of the antimcrobial ball and then sintered at 100$0^{\circ}C$ Ag-containing HAp(HAp-Ag) was prepared by incorporating $Ag^+$/ions in HAp crystals through an ion-exchange reaction in solutions containing 0.01M $AgNO_3$. The antimicrobial effect of HAp-Ag for bacteria such as Escherichial coli and Staphylococcus aureus has been Investigated. The concentrations of silver in the antimicrobial ball was determined by inductively coupled plasma and the amount of $Ag^+$ions was 9.0$\mu\textrm{g}$/g. The HAp-Ag exhibited excellent antimicrobial effect for bacteria such as E. coli and S. aureus. The bactericidal activity was considered to be caused by direct contact of bacteria with $Ag^+$ions in the HAp crystals. The HAp would likely to be possible as a carrier of antimicrobial metal ions such as Ag, Cu, and Zn by recycling of waste sludge in the semiconductor fabrication process.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.441-448
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• 2016

Heavy metal removal study is conducted from synthetic waste water by reduction and oxidation(redox) reaction of Cu-Zn metal alloy and adsorption reaction of aluminium silicate. Heavy metal whose ionization tendency is smaller than zinc are reducted in an aqueous solution, and the concentration of ionized zinc is reduced by adsorption reaction. The average diameter of metal alloy micro fiber is about $200{\mu}m$, and the surface area is wide enough to get equilibrium in a single cycle treatment. A single cycle treatment of redox reaction of Cu-Zn metal alloy, could remove 100.0 % of Cr(III), 98.0 % of Hg, 92.0 % of Sn and 91.4 % of Cu respectively. An ionization tendency of chromium is very close to zinc, but removal efficiency of chromium by redox reaction is significant. This result shows that trivalent chromium ion is expected to generate hydroxide precipitation with $OH^-$ ion generated by redox reaction. Zinc ion generated by redox reaction is readily removed by adsorption reaction of aluminium silicate in a single cycle treatment. Other heavy metal components which are not perfectly removed by redox reaction also showed very high removal efficiency of 98.0 % or more by adsorption reaction. Aluminium ion is not increased by adsorption reaction of aluminium silicate. That means heavy metal ion removal mechanism by adsorption reaction is turned out to be not an ion exchange reaction, but an adsorption reaction.