• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.17-28
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• 2018

In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon material. Comparison study was also conducted by production of activated carbon from coconut shell (CCNS), Pinus, and Avicel, and each activated carbon was characterized by chemical composition, Raman spectroscopy, SEM analysis, and BET analysis. The amount of solid residue after thermogravimetric analysis of biomass samples at the final temperature of $750^{\circ}C$ was SAL > CCNS > Pinus > Avicel, which was the same as the order of activated carbon yields after catalytic activation. Specifically, SAL-derived activated carbon showed the highest value of carbon content (91.0%) and $I_d/I_g$ peak ratio (4.2), indicating that amorphous large aromatic structure layer was formed with high carbon fixation. In addition, the largest changes was observed in SAL with the maximum BET specific surface area and pore volume of $2341m^2/g$ and $1.270cm^3/g$, respectively. Furthermore, the adsorption test for three kinds of organic pollutants (phenol, 2,4-Dichlorophenoxyacetic acid, and carbofuran) were conducted, and an excellent adsorption capacity more than 90 mg/g for all activated carbon was determined using 100 ppm of the standard solution. Therefore, SAL, a condensed structure, can be used not only as a nanoporous carbon material with high specific surface area but also as a biosorbent applied to a carbon filter for remediation of organic pollutants in future.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.246-251
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• 1999

This experiment was carried out to elucidate and investigate the changes in the content of antioxidants and the activities of antioxidant enzymes in the leaves of soybean subjected to water stresses. The results obtained were as follows; Leaves of soybeans subjected to water stresses have showed the differences in the activities of the antioxidant enzymes. In eunhakong, the activity of APOX was increased within a few days, but that of GR was decreased, whereas the activities of APOX and GR were gradually decreased in eunhakong. The activity of MDHAR of the leaves of eunhakong subjected to drought stress was gradually increased within 4days, whereas that of flooding was increased within 2days. We are supposed that the activities of APOX and MDHAR are coupled to maintain ascorbate concentration. In eunhakong, the relative activity of DHAR subjected to flooding was higher than that of drought. These results imply that DHAR is the only enzyme participating in the regeneration of ascorbate when the activity of MDHAR was limited by the deficiency of NADPH. The contents of ascorbate and reduced glutathione subjected to drought stress decreased continually, whereas those subjected to flooding stress recovered after five days of treatment.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.568-577
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• 2015

To protect skin problems, new natural material alternative to synthetic antioxidants has been extensively selected from natural sources such as plants, animals, and microorganisms. Poncirus trifoliata of those has been widely used as treatment of allergy, chronic inflammatory diseases, and natural antioxidant. In recent days, microbial fermentation to natural products has been reported to increase feasibly their bioavailability. Accordingly, we performed the fermentation using hot water extract of Poncirus trifoliata by isolated Leuconostocs sp. strain JYK and investigated the change of antioxidative activity. Antioxidative material such as hesperidine naringine, imperatorin, and luteolin was found in hot water extract of Poncirus trifoliata. Total phenolics compounds and flavoniods in hot water extract were $71.2{\pm}4.58GAE(mg/g)$ and $25.1{\pm}4.12$ hesperidine(mg/g), respectively. After fermentation, their values were $89.2{\pm}13.47GAE(mg/g)$ and $31.0{\pm}4.06$ hesperidine(mg/g), respectively. After fermentation, ABTS[2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)] and DPPH(1,1-diphenyl-2-picrylhydrazyl) radical were highly enhanced from $70.2{\pm}9.01$ to $86.2{\pm}3.72$ and $18.7{\pm}1.81$ to $26.6{\pm}4.06$, respectively. Thus microbial fermentation offers a tool to further increase the bioactive potential of Poncirus trifoliata.

• Applied Biological Chemistry
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• v.12
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• pp.33-41
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• 1969

1. Crude cellulase extracted from wheat bran media of Chaetomium globosum with pH 7.0 McIlvaine buffer was fractionated by precipitation with ammonium sulfate and by treatment with the cellulose powder, DEAE-Sephadex A-25 and Amberite XE-65 (IRC-50) column chromatography. 2. Consquently two cellulases C-1 and C-2 were obtained by cellulose column chromatography. Cellulose C-1 was a powerful CMC-saccharifying and CMC-liquefying activity but cellulose C-2 was stronger CMC-liquefying activity compared to CMC-saccharifying activity and cellulase C-2 had smaller protein than that of cellulose C-1. And cellulose C-2 was fractionated by DEAE-Sephadex A-25 column chromatography into cellulase C-1-1 and cellulose C-1-2. 3. It can be obtained, therefore, that cellulose produced Chaelomium globosum consisted, at least, of three cellulases C-2, C-1-1 and C-1-2. 4. Cellulose C-1-1 was homogenous in the ultraviolet and the ultracentrifuge pattern. And cellulose C-1-1 had enzyme for CMC-saccharifying activity. 5. The optimum pH for the enzyme activity of cellulose C-1-1 was 4.0 in any methods of meas urement reducing sugar and viscosity. The optimum temperature was $40^{\circ}C$ in any methods. 6. The pH stability of cellulase C-1-1 was within pH 5.0 to pH 6.0 at $40^{\circ}C$ and fairly stable in acidic solution. 7. The heat stability was below $50^{\circ}C$ at pH 4.0 and complete heat inactivation of this cellulase occurred at $70^{\circ}C$.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.557-560
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• 2009

In this study, a new wet etching method and the solution for thinning the glass with the thickness below $100{\mu}m$ were investigated. For the preparation of etching solution with low hydrofluoric acid, it was effective to use $NH_4F$ or $NH_4HF_2$ as a main ingredient with the addition of sulfuric acid or nitric acid. Influence of the composition of mixed acid solution and the temperature on the etching rate was investigated. The addition of anionic surfactant provides the function to prevent the adhesion of sludge generated by the etching reaction. A new wet etching pilot device equipped with streaming generation parts was used to test etching of commercial non-alkali glass and soda lime glass. The non-alkali glass with the thickness of 640 ${\mu}m$ and soda lime glass with the thickness of $500{\mu}m$ were etched to $45{\mu}m$ and $100{\mu}m$, respectively, by using the pilot device. After the etching by pilot device, the roughness degree of the glass surface was maintained at $0.01{\sim}0.02{\mu}m$.

• 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%.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.598-603
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• 2015

In this study, electrochemical properties of pitch-based activated carbon fibers (ACFs) were investigated by different heat-treatment temperature of the pitch-based ACFs in order to improve the specific capacitance of electric double-layer capacitor (EDLC). The ACFs were prepared by different heat-treatment temperatures of 1050 and $1450^{\circ}C$, after activation with 4 M KOH at $800^{\circ}C$ using stabilized pitch fiber. The specific surface area of prepared ACFs increased from $828m^2/g$ to $987m^2/g$, also the micropore and mesopore volumes of prepared ACFs were increased. These results because pore was produced by desorbing oxygen and hydrogen elements within the ACFs, and pore size was increased by contraction ACFs by heat-treatment process. Because of the porous properties, the specific capacitance was increased from 73 F/g to 119 F/g using cyclic voltammetry with 1 M $H_2SO_4$ at scan rates of 5 mV/s.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.666-671
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• 1999

In this work, sulfonated poly(phenylene sulfide) (SPPS) was prepared by demethylation with aqueous NaOH solution after poly[methyl[4-(phenylthio)phenyl]sulfonium trifluoromethanesulfonate](PPST) was sulfonated with fumic sulfonic acid(10% $SO_{3}-H_{2}SO_{4}$). PPST soluble in organic solvents was synthesiszed by self-condensation polymerization of methyl-(phenylthio)phenyl sulfoxide(MPPSO). SPPS showed IR bands of asymmetric O=S=O stretching at $1200cm^{-1}$ and S-O stretching at $621cm^{-1}$ from $-SO_{3}H$ group. From the result, it could be known that sulfonic acid groups were introduced to poly(phenylene sulfide). when PPST was sulfonated for 12hr at $150^{\circ}C$, 1.48 sulfonic acid groups were introduced per repeat unit. The weight average molecular weight(Mw) of PPST and SPPS determined by high temperature GPC were 118323 and 131204, respectively. The SPPS exhibited adsorption capacity of ammonia gas $9.67mmol\;NH_{3}/g$ and it was much higher than that of active carbon or silica gel.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.574-581
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• 2008

The optimum regeneration conditions for the regeneration of three way spent catalysts (TWCs), which were taken from automobiles with different driving conditions, were investigated to evaluate the suitability as alternative catalysts for removing VOCs. The spent catalysts were washed with five different acids ($HNO_3$, $H_2SO_4$, $C_2H_2O_4$, $C_6H_8O_7$, and $H_3PO_4$) to remove contaminants and examine the optimum conditions for recovering the catalytic activity. The physicochemical properties of spent and its regenerated TWCs were evaluated by using nitrogen adsorption-desorption isotherms, XRD, and ICP. The relative atomic ratios of contaminants and platinum group metals (PGMs) of the spent TWCs were greatly dependent on the placed positions. The main contaminants formed were lubricant oil additives and metallic components. Also, the regeneration treatment increased the PGMs ratio, BET surface area, and average pore diameter of TWCs. The catalytic activity results indicated that the spent TWCs have the possibility for removing VOCs. Moreover, the employed acid treatments greatly enhanced the catalytic activity of the spent TWCs. Especially, nitric and oxalic acids provided the most improvement in the catalytic behavior. The catalytic activities of the regenerated TWCs were significantly influenced by the containing platinum ratios rather than the removal ratios of contaminants and the changes in the structural properties offered by the acid treatments.

• Journal of Mushroom
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• v.13 no.1
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• pp.56-62
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• 2015

A lipase producing bacterium was isolated from button mushroom bed, which showing high clear zone on agar media containing Tributyrin as the substrate. The strain was identified as Burkholderia cepacia by analysis of 16S rDNA gene sequence. Crude lipase (CL) was partially purified from 70% ammonium sulfate precipitation using the culture filtrate of B. cepacia. Immobilized lipases were prepared by cross-linking method with CL from B. cepacia and Novozyme lipase (NL) onto silanized Silica-gel as support. Residual activitiy of the immobilized CL (ICL) and immobilized NL (INL) was maintained upto 61% and 72%, respectively. Biodiesel (Fatty acid methyl ester, FAME) was recovered by transesterification and methanolysis of Canola oil using NaOH, CL and ICL as the catalysts to compare the composition of fatty acids and the yield of FAME. Total FAME content was NaOH $781mg\;L^{-1}$, CL $681mg\;L^{-1}$ and ICL $596mg\;L^{-1}$, in which the highest levels of FAME was observed to 50% oleic acid (C18:1) and 22% stearic acid (C18:0). In addition, the unsaturated FAME (C18:1, C18:2) decreased, while saturated FAME (C16:0, C18:0) increased according to increasing the reaction times with both CL and ICL, supporting CL possess both transesterification and interesterification activity. When reusability of ICL and INL was estimated by using the continuous reaction of 4 cycles, the activity of ICL and INL was respectively maintained 66% and 79% until the fourth reaction.