• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.304-310
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• 1978

The relative permeabilities, distribution coefficients and diffusion coefficient of some salts which are important components in blood plasma through a poly(HEMA) membrane were measured. The crosslinker which was used for preparing the membrane was tetraethylene glycol dimethacrylate(TEGDMA), the weight percentage of the latter was about 2.8. We found that the diffusion coefficients ($D_m$) of the solutes decrease exponentially with increasing molecular weight, and also that $D_m$'s decrease linearly (except urea) with cylindrical radius (a). These facts were explained by a sieve pore flow model. The relative permeability and diffusion coefficient of urea at various temperature were larger than those of other solutes such as glycine, ${\beta}$-alanine, D-glucose, saccharose and maleic acid. The result indicates that the poly(HEMA) membrane might be suitable for hemodialysis application.

• Parasites, Hosts and Diseases
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• v.29 no.2
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• pp.113-120
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• 1991

When the component proteins in crude saline extract of 13-week old adult Paragonimus westermani were observed by non-denaturing discontinuous-polyacrylamide gel electrophoresis (Disc-PAGE), 8 distinct bands were clearly recognized. Molecular weight (MW) of each band protein, numbered in sequence from cathodal side which appeared in 10% separating gel, was measured first by Ferguson plot utilizing different gel concentrations from 10% to 4.5%. MW of band 1 Protein (known as egg Protein) was 440 kDa. And MW of other band Proteins were: 386 kDa in band 2, 17.4 kDa in band 3, 17kDa in band 4, 14.3 kDa in band 5, 46 kDa in band 6, 38 kDa in band 7 and 23 kDa in band 8. When the proteins in the crude extract were separated into fractions by molecular sieve chromatography through 1.6 (Φ)×70cm sired Sephacryl 5-300 Superane column and revisualized by Disc-PAGE in 8% gel, the sequence of fluted proteins was band 1, band 2, band 6, band 7 and bands 3,4,5 and 8. This elusion profile confirmed MW of each band protein in the crude extract as measured by Ferguson plot.

• The Journal of Natural Sciences
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• v.5 no.1
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• pp.67-75
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• 1992

In the our country, especially in Yeongil and Wolsung area, abundant authigenic zeolites are found from the tuffaceous sediments and volcanic rocks of Miocene age showing wide variation in their mineralogy and abundance from horizon to horizon. The principal zeolite species identified are clinopti-lolite. mordenite. heulandite. ferrierite, and erionite. etc. Zeolite minerals are widely used in many countries in the following applications; (a) in air separation adsorption processes; (b)as desiccants; (c)in inorganic building materials; (d)in papermaking; (e)in fertilizers; (f)as soilconditioners-this application is based upon the ability of the zeolite to ion exchange with soil nutrients; (g)in the treatment of radioactive wastes; and (h)as adsorbents for toxic gases, etc. In the present paper, using natural zeolite mordenite treated with IN hydrochloric acid or IN sodium chloride solution as column packings, separation characteristics of argon, nitrogen, carbon monoxide, and methane gases have been studied by gas chromatography. By the use of mordenite treated with hydrochloric acid solution, the tailing peak of methane showed from untreated mordenite was satisfactorily reduced, although it was difficult to separate it from carbon monoxide with a column activated at $300^{\circ}C$. Using a column activated at $350^{\circ}C$, methane could be separated from carbon monoxide easily but only carbon monoxide eluted as a bad defined peak. Mordenite treated with sodium chloride solution was generally similar to chromatograms obtained by using the untreated mordenite. Both the above chemical treatments of mordenite had little effect on the separations of argon and nitrogen. The separations and the HETP values obtained from natural zeolite mordenite treated with continuously hydrochloric acid and sodium chloride solutions were almost identical with those obtained with synthetic molecular sieve 5A zeolite. On the other hand, the efficiency of column was good in the range 20~3Oml/min of the carrier helium gas rate.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.659-665
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• 2010

A cis-epoxysuccinate hydrolase (CESH) from Bordetella sp. BK-52 was purified 51.4-fold with a yield of 27.1% using ammonium sulfate precipitation, ionic exchange, hydrophobic interaction, molecular sieve chromatography and an additional anion-exchange chromatography. The CESH was stable in a broad range of temperature (up to $50^{\circ}C$) and pH (4.0-10.0) with optima of $40^{\circ}C$ and pH 6.5, respectively. It could be partially inhibited by EDTA-$Na_2$, $Ag^+$, SDS, and DTT, and slightly enhanced by $Ba^{2+}$ and $Ca^{2+}$. The enzyme exhibited high stereospecificity in D(-)-tartaric acid (enantiomeric excess value higher than 99%) with $K_m$ and $V_max$ values of 18.67 mM and $94.34\;{\mu}M$/min/mg for disodium cis-epoxysuccinate, respectively. The Bordetella sp. BK-52 CESH gene, which contained 885 nucleotides (open reading frame) encoding 294 amino acids with a molecular mass of about 32 kDa, was successfully overexpressed in Escherichia coli using a T7/lac promoter vector and the enzyme activity was increased 42-times compared with the original strain. It may be an industrial biocatalyst for the preparation of D(-)-tartaric acid.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.793-802
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• 2009

Adsorption properties were estimated for the organic silicon compounds (siloxanes) in an actual landfill gas (LFG) using adsorbents such as coconut activated carbon, coal activated carbon, silica gel, sulfur adsorbent, carbonized sludge, and molecular sieve 13X. Coconut activated carbon showed the highest removal efficiency of more than 95%. The desorption of hexamethyldisiloxane (L2) from the adsorbent, however, resulted in the remarkable concentration variation of the compound in the treated gas. Silica gel, which had high adsorption capacity for L2 in single substance adsorption experiment in the other study, could not remove the component in the actual landfill gas while it adsorbed well octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in the LFG. Therefore the elimination of hexamethyldisiloxane is an important factor to determine the level of total organosilicon compound in pretreated landfill gas. Moreover, the L2 from the actual landfill gas was effectively adsorbed by the serial adsorption test using two columns packed with coconut activated carbon which has the great capacity of siloxanes removal among others. In order to utilize efficiently LFG as a renewable energy, the emission and adsorptive characteristics of the substance to be treated should be considered for the organization, operation, and management of pretreatment process.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.634-638
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• 2004

Titanium silicalite-1 (TS-1) molecular sieve was produced by microwave heating of amorphous titanium-containing solid precursors after impregnation with aqueous TPAOH solution. $SiO_2-TiO_2$ xerogel, sub-micron sized $SiO_2-TiO_2$ prepared by thermal plasma process, and Ti-containing mesoporous silica, Ti-HMS, were tested as the solid phase substrates. Highly crystalline product was obtained within 30 min. after microwave irradiation with yields over 90% using $SiO_2-TiO_2$ xerogel, which showed essentially identical physicochemical properties to TS-1 prepared by conventional hydrothermal method. Excellent catalytic activity was also obtained for 1-hexene epoxidation using $H_2O_2.\;SiO_2-TiO_2$ particles prepared by thermal plasma and Ti-HMS were found inferior as a substrate for TS-1, probably due to difficulties in wetting the surface uniformly with TPAOH.

• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.259-266
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• 1991

In cytosolic (raction of adult Paragonimus westermani, superoxide dismutase activity was identified (4.3 units/mg of specific activity) using a xanthine-xanthine oxidase system. The enzyme was purified 150 fold in its activity using the ammonium sulfate precipitation, DEAE-Trisacryl M anion-exchange chromatography and Sephadex G-100 molecular sieve chromatography. The enzyme exhibited the enhanced activity at pH 10.0. The enzyme activity totally disappeared in 1.0mM cyanide while it remained 77.8% even in 10 mM azide. These findings indicated that the ensyme was Cu, Zn-SOD type. Molecular mass of the enzyme was estimated to be 34 kDa by gel filtration and 17 kDa on reducing SDS-polyacrylamide gel electrophoresis which indicated a dimer protein.

• Journal of Hydrogen and New Energy
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• v.21 no.1
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• pp.72-79
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• 2010

This paper is studying the selective separation of methane and carbon dioxide which are the main ingredients of biogas. Adsorption performance of molecular sieve 13x for carbon dioxide seems to be reasonable. In this experiments carbon dioxide contains about 3~5 ppm of methane and it is impossible to obtain high purity carbon dioxide. Applying the low temperature technique, it is possible to separate methane and carbon dioxide from bio gas. PRO II simulation shows results a small change of liquefaction temperatures and no difference with the used thermodynamic models. Applying low temperature technique, It is possible to separate carbon dioxide and methane from biogas.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3065-3072
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• 2013

Direct synthesis of $H_2O_2$ and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active $Au^0$ species for $H_2O_2$ synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in $H_2O_2$ synthesis as $CH_3OH/H_2O$ ratio of solvent changed. $H_2O_2$ decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of $O_2/H_2$ ratio on $H_2O_2$ concentration, $H_2$ conversion and $H_2O_2$ selectivity revealed a relationship between $H_2O_2$ generation and $H_2$ consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of $O_2/H_2$ ratio and $60^{\circ}C$. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, $H_2$ conversion and oxidative desulfurization selectivity of $H_2$ were presented.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.103-108
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• 1997

A series of batch tests were conducted to evaluate the design parameters for the application of soil washing techniques to the hydrophobic organic compounds (HOCs)-contaminated soil using mixed surfactants. Because the mixed surfactants form different structures of molecular aggregates from single surfactant, they were applied to improve the washing efficiency. Kinds of surfactants added, mixing ratio, and total concentration of mixed surfactants were evaluated. The uncontaminated soil was obtained from a country hill near Nock-Chun Station in Seoul. The portion of soil passing #4 (4.75 mm) sieve was used. The pH, organic contents and cation exchange capacity were 4.4, 1.6% and 4.08 meq/100 g, respectively The soil was artificially contaminated by n-dodecane. The 5% solution of OA-5 and OA-14 (1:1) showed 86% washing efficency. The 4% solution of SDS and OA-5 (1:1) showed 95% washing efficiency.