• Membrane Journal
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• v.5 no.1
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• pp.26-34
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• 1995

In this study, polysulfone was carboxylated(CPSf), as a method of introducing carboxyl group to polymer main chain using direct lithiation reaction. Then, poly(1-alkyl-4-vinylpyridinium iodide-co-divinylbenzene) (MeVpI-DVB) containing pyridinium cation which has an anion selectivity as a fixed carrier was synthesized. And polymer membranes were prepared by mixing CPSf and MeVpI-DVB. Characteristics and permeation of membranes were investigated. As a result of synthesizing CPSf/MeVpI-DVB, blend was formed, not new copolymer. As the content of CPSf amount increasing, thermal stability of membranes was increasing. Ion exchange capacity was 1.0~1.8(meq/g dry mem.) and water content was 0.16~0.26(g $H_2{O}$)/g dry mem.) and fixed ion concentration was 6.4~7.3(meq/g $H_2{O}$) in synthetic membranes. The $Cl^-$ flux showed an increase due to the increase of CPSf content.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.130-136
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• 1996

This study was carried out easily to determine the refreshing time of natural Zeolite used for the clearing of Livestock waste water and to investigate the relationship between EC of solution and adsorption amount on Zeolite. During the adsorption reaction, EC of supernatant solution decreased till the equilibrium was reached and kept a constant level after it. EC was greatly decreased with the concentration of solution and the magnitude of adsorbent. Decrease in EC of suspension was found to be lesser in addition of Na-Zeolite than Ca-Zeolite. EC change of Livestock waste water was shown to be similar tendency to that of the simulated waste water. On the cumulative adsorption isotherm, the EC of suspension increased until the EC value of the initial solution as the increase in treatment times. Therefore, it is apparent that the exchange point of natural zeolite should be in the vicinity of the EC value of initial waste water.

• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.193-199
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• 1972

Bentones from Korean bentonites were first prepared by reacting bentonites with high molecular weight imidazolines. The cation exchange capacity of bentonites was found more than 100meq/100g sample. Greases were then prepared by dispersing bentones into a lubricating oil and milling through a three-roll dispersion mill. Consistency in microscale, oxidation stability (static), water resistance, and wear property of the greases were tested by the ASTM methods, and good experimental results were obtained.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.60-60
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• 1993

새로운 항생물질을 개발하기 위하여 토양으로부터 분리한 균주를 액체배지에서 배양하여 그 배양액을 여러 검정균에 대하여 종이디스크법으로 항균효력을 측정하였다. 그 결과 G(＋), G(－)균에 강한 항균효력을 보인 토양균 SNUS 9101-55와 C. aibicans와 같은 진균류에 항균력을 보인 토양균 SN-US 9101-68을 선택하여 각각의 배양액에서 항생물질을 분리하고, 분리한 항생물질의 구조를 규명하고자 하였다. 토양균 SNUS 9101-55의 배양액으로부터 항생물질을 분리하기 위하여 양이온 교환수지 관 크로마토그래피와 셀룰로오스 관 크로마토그래피를 수행하여 시료 AMJ-I-212-B를 얻었다. 시료 AMJ-I-212-B의 IR, $^1$H-NMR, FAB-MS 스펙트럼을 얻어 분리한 항생물질의 구조를 분석하고 Sakaguchi test와 같은 정색반응을 통하여 그 발색단을 동정하여 이 항생물질의 구조가 스트렙토마이신과 동일하다는 것을 확인하였다.

• The Journal of Natural Sciences
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• v.8 no.1
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• pp.41-45
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• 1995

A. partially decationized Y zeolite was pretreated under specific conditions. It was found this calcinated zeolite retains its separation properties for mixtures of the gases hydrogen, nitrogen, oxygen, carbon monoxide, and methane but has much lower affinity for water molecules than untreated, e.g., zeolites A type or X type. The observed effect is discussed on the basis of the results of adsorption measurements on the adsorption capacities, isotherms, and heats of adsorption.

• Journal of the Mineralogical Society of Korea
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• v.15 no.2
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• pp.114-121
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• 2002

Buffer capacities for two Bo horizon soils or Andisols developed from different parent materials have been investigated. The titration curves from column leaching experiment show that buffering occurred at pH 4.0 and 6.0. The buffer intensity or soil developed from pyroclastic materials (P-soil) is higher than that from basalts (B-soil). From batch test we have found that proto-imogolite and/or imogolite may control Al solubility as well as $Al(OH) _3$in the moderate acid condition. The buffer intensities ($\beta$) of P-soils were plotted on the theoretical buffering curve of $Al(OH)_3$, while $\beta$ of B-soils approached to that of proto-imogolite, which shows the solubility of short-range-order materials in P-soil control the buffer capacity. Buffering at pH 6.0 is thought to be the result of dissolution of some silicate clays and exchange reactions between $H^{+ }$and base-forming cations. Considering the amount of annual acid precipitation, aluminum solubility of Andisols, and the low BS (Base Saturation percentage), it can be predicted that prolonged acid precipitation will reduce the buffer capacity of soils and lead to soil acidification.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.327-332
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• 1999

Manganese (Mn) oxides in soils have been a research subject since they react with nutrients and contaminants and Mn itself is an essential element for plant growth. Birnessite was synthesized in the presence of iron (Fe) in the precipitating solution. Influence of Fe, one of common elements in soils, on crytallinity, morphology, and chemical reactivity of birnessite was examined using X-ray diffraction (XRD), electron microscope, canon exchange capacity (CEC), and chromium (Cr) oxidation capacity. With increasing Fe concentration in the precipitating solution, crystallinity and crystal size decreased. Hexagonal plates of the birnessites formed at low Fe concentration were dominant and replaced more and more by aggregate of small particles with increasing the Fe concentration. There is no significant change in CEC with changing the Fe concentration. Chromium oxidation capacity of the birnessite increased with increasing the Fe concentration. Iron in the precipitating solution poisoned crystal growth by adsorption on the surface and increased nucleation. Since Fe is a common constituent under pedogenic environment and Fe and Mn oxides often coexist in Mn oxide nodules, the birnessite with small particle, low crystallinity, and high chemical reactivity is the form which is more likely to be formed in soils. The high CEC ($140cmol_ckg^{-1}$) and oxidation capacity of birnessite indicate that birnessite can be used in environment and agriculture.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.95-101
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• 1984

Aquation reaction kinetics of $[Cr(en)_2Cl_2]^+$complex was carried by the electric conductivity method. Its temperature range was $15^{\circ}C$ to $30^{\circ}C$ and pressure was varied up to 2,000 bars. The reaction rate was increased with increasing temperature, but was reversed to increasing pressure. The activation volume(${\Delta}V^{\neq}$) was increased with increasing temperature and decreased with increasing pressure. At $25^{\circ}C$ and 1 bar it was fairly small positive value, $1.82cm^2/mole$. Activation entropy change(${\Delta}S^{\neq}$) $was calculated as small negative value,-9.019 eu, at $25^{\circ}C$ and 1bar. Referring to the thermodynamic parameters, it was estimated that aquation reaction was proceeded by the interchange-dissociation(Id) mechanism.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.255-269
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• 2001

The geochemical studies on groundwater in the borehole, which is straddled by multi-packer (MP) system, were carried out from a volcanic terrain in the Yeosu area. The pH of groundwater collected from selected sections in the MP-installed borehole is much higher (up to 9.6) than that of the borehole groundwater (7.0-7.9) collected using conventional pumping technique. Hydrochemistry shows that the groundwater has a typical chemical change with increasing sampling depth, suggesting that the groundwater is evolved through water-rock interaction along the fracture-controlled flow paths. The groundwater from the deeper part (138-175 m below the surface) in borehole KI is characterized by the Ca-C11 type with high Ca (up to 160 mg/L) and Cl (up to 293 mg/L) contents, probably reflecting seawater intrusion. The groundwater also has high sodium and sulfate contents compared to the waters from other boreholes. These observed groundwater chemistry is explained by the cation exchange, sulfide oxidation, and mixing process with seawater along the flow path.

• Journal of the Korean Chemical Society
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• v.54 no.3
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• pp.300-309
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• 2010

The ability of sodium-exchanged clay particles as an adsorbent for the removal of commercial dyes, Methylene blue (MB) and Malachite green oxalate (MG) from aqueous solutions has been investigated under various experimental conditions. The effect of the experimental parameters, such as pH solution, agitation time, adsorbate concentration and adsorbent dose were examined. Maximum adsorption of dyes, i.e. >90% has been achieved in aqueous solutions using 0.03 g of clay at a pH of 7 and 298 K for both dyes. The adsorption process was a fast and the equilibrium was obtained within the first 5 min. For the adsorption of both MB and MG dyes, the pseudo-second-order reaction kinetics provides the best correlation of the experimental data. The adsorption equilibrium results follow Langmuir and Dubini-Radushkevich (D-R) isotherms with high regression coefficients $R^2$ > 0.98. The mean free energies $E_a$ of adsorption from D-R model were 3.779 and 2.564 kj/mol for MB and MG respectively, which corresponds to a physisorption process.