• KSBB Journal
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• v.24 no.4
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• pp.361-366
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• 2009

Response surface methodology (RSM) was used for optimization the fraction conditions of xylose from pepper stem with dilute sulfuric acid. The independent variables were acid concentration in the range of 1.134 to 2.866%, reaction temperatures in the range of 142.68 to $177.32^{\circ}C$, and hydrolysis time in the range of 6.34 to 23.66 min. were studied. The dependent variables were xylose yield from pepper stem, and the production of by-products, for example, furfural, acetic aicd, HMF etc. Experimental results had a good match with statistical result. The maximum xylose yield obtained in this experiment was 71% concentration.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.295-296
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• 2003

키토산은 셀룰로오스 다음으로 자연계에 많이 존재하는 천연 고분자인 키틴을 탈아세틸화 시킨 것으로서, 많은 아민기를 가지고 있는 것이 특징이다[1]. 키토산은 아민기에 의한 항균성이 뛰어나기 때문에 섬유제품의 항균 가공제로 이용되고 있다. 그러나 키토산은 다른 천연고분자와 마찬가지로 용융가공성이 없기 때문에 섬유, 멤브레인 등으로의 성형은 묽은 산 수용액으로 만든 용액을 가공하는 방법을 이용하고 있다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.163-164
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• 2003

키토산은 셀룰로오스 다음으로 자연계에 많이 존재하는 천연 고분자인 키틴을 탈아세틸화 시킨 것으로서, 많은 아민기를 가지고 있는 것이 특징이다[1]. 키토산은 아민기에 의한 항균성이 뛰어나기 때문에 섬유제품의 항균 가공제로 이용되고 있다. 그러나 키토산은 다른 천연고분자와 마찬가지로 용융가공성이 없기 때문에 섬유, 멤브레인 등으로의 성형은 묽은 산 수용액으로 만든 용액을 가공하는 방법을 이용하고 있다. (중략)

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.108-117
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• 2017

Laver, Porphyra, is distinctive for its high content of proteins and polysaccharides such as porphyran and hemicellulose. The chemical properties of the polysaccharides extracted with different extraction methods such as hot water, dilute acid(pH 4.0) or alkali solution(2N NaOH) were examined to investigate the suitable extraction conditions for porphyran and hemicellulose from laver. For porphyran extraction, dilute acid solution was more preferable to hot water and alkali solution because of its higher 3,6-anhydrogalactose content and lower protein content. However, alkali solution was more suitable to extract the hemicellulose because of higher mannose content indicating the extraction of mannan. To decrease contamination of the polysaccharides with protein, the dried lavers were pretreated with enzymes (Protamex, Flavourzyme, Alcalase, Viscozyme) before hot water extraction. All enzyme pretreatments increased the yield of polysaccharides by compared with control (enzyme unpretreated) and Flavourzyme pretreatment was most effective to decrease protein contamination in the polysaccharide. All viscosities of porphyran solutions pretreated by enzymes were lower compared to the control porphyran solution and showed pseudoplastic behavior with yield stress. In case of alkali extraction of residues obtained after enzyme hydrolysis and hot water extraction, protease pretreatment increased the mannose contents in the polysaccharide while the xylose content was increased by Viscozyme pretreatment.

• KSBB Journal
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• v.24 no.3
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• pp.267-272
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• 2009

During a dilute acid hydrolysis, degradation products are formed or liberated by pre-treatment of lignocelluloses depend on both the biomass and the pretreatment conditions such as temperature, time, pressure, pH, redox conditions, and addition of catalysts. In lignocellulosic biomass, sugars can be degraded to furfural which is formed from pentoses and 5-hydroxymethulfurfural (HMF) from hexoses. 5-HMF can be further degraded, forming levulinic acid and formic acid. Acetate is liberated from hemicellulose during hydrolysis. Some decomposed compounds hinder the subsequent bioconversion of the solubilized sugars into desired products, reducing conversion yields and rates during fermentation. In the present work, samples of rapeseed strawwere hydrolyzed to study the optimal pretreatment condition by assessing yields of sugars and decomposed products obtained under different reaction conditions ($H_2SO_4$ 0.5-1.25% (w/w), reaction time 0-20 min and temperature range 150-220 C). A careful analytical investigation of acid hydrolyzate of rapeseed straw has not yet been undertaken, and a well-closed mass balance for the hydrolyzate in general is necessary to verify the productivity and economic predictions for this process.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.191-194
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• 1998

Diester형 분산염료란 염료 분자 구조 중에 diester기를 함유하고 있어 염색은 일반 분산염료와 동일하게 수행하고, 염색 후 묽은 알칼리 용액으로 처리하면 섬유 표면에 존재하는 미고착 염료들의 ester기가 가수분해되어 sodium carboxylate가 생성되면서 염료가 수용성으로 변하여 쉽게 제거되는 성질을 가진 염료를 말한다. (중략)

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.3
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• pp.79-89
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• 2011

The wasted corn stalk from Gangwon province is composed of 44.6 % glucan, 19.0 % xylan, 23.8 % lignin, 4.5 % ash and 8.1 % others. Statistical analysis, full factorial design, revealed that temperature was the most influential factor in the dilute sulfuric acid pretreatment and that the influence of temperature on xylose yield was 3.5 and 3.2 times higher than those of treatment time and acid concentration, respectively. Temperature was also the most influential factor for glucose yield in the pretreatment but it was less than 5 % throughout the pretreatment. Although minor sugar yield was observed when microwave or ultrasonication was solely introduced as a pretreatment method, the complex method incorporating microwave or ultrasonication into dilute sulfuric acid pretreatment enhanced sugar yield significantly. In particular, xylose yield was doubled when microwave and dilute sulfuric acid treatment was sequentially applied. The optimization of pretreatment and enzymatic hydrolysis as well as the investigation on the complex pretreatment in detail are left for further study.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.67-70
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• 2008

Biological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically, and with dilute or concentrate mineral acids. In this study, dilute sulfuric acid used as a catalyst for the hydrolysis of rapeseed straw. The purpose of this study is to optimize the hydrolysis process in a 15ml bomb tube reactor and investigate the effects of the acid concentration, temperature and reaction time on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). Statistical analysis was based on a model composition corresponding to a $3^3$ orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of rapeseed straw. The obtained optimum conditions were: acid concentration of 0.77%, temperature of $164^{\circ}C$ with a reaction time of 18min. Under these conditions, 75.94% of the total xylose was removed and the hydrolysate contained 0.65g $L^{-1}$ Glucose, 0.36g $L^{-1}$ Arabinose, 3.59g $L^{-1}$ Xylose, 0.51g $L^{-1}$ Furfural, 1.36g $L^{-1}$ Acetic acid, and 0.08g $L^{-1}$ 5-hydroxymethylfurfural.

• Journal of the Korean Magnetics Society
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• v.16 no.4
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• pp.221-227
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• 2006

We have synthesized uniform nanometer sized magnetite particles using chemical coprecipitation technique through a sonochemical method with surfactant such as oleic acid. Magnetite phase nanoparticles could be observed from X-ray diffraction. Magnetite nanoparticles is surface phase morphology and biopolymer-microspheres for Application Medical. Magnetite nanoparticles coated biopolymer. Atomic Force Microscope (AFM) was used to image the coated nanoparticles. Magnetic colloid suspensions containing particles with sodium oleate, chitosan and $\beta$-glucan have been prepared. The morphology of the magnetic biopolymer microsphere particles were characterized using optical microscope. Magnetic hysteresis measurement were performed using a superconducting quantum interference device (SQUID) magnetometer at room temperature to investigate the magnetic properties of the biopolymer microspheres and magnetite coated biopolymer including magnetite nanoparticles. Magnetic Resonance (MR) imaging was used to investigate biopolymer coated nanoparticles and biopolymer microspheres.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.138-143
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• 1997

Acid-catalyzed hydrolysis of 3,3-bis(methylthio)-2-propen-1-phenyl-1-one derivatives were studied kinetically in concentrated aqueous hydroperchloric acid(-Ho < 2.23) at $30^{\circ}C.$ The substituent effect, analysis of hydrolysis product, hydration $parameter({\omega} & {\phi}$) from the Bunnett equation and the Bunnett-Olsen equation on the rate indicate that the acid-catalyzed hydrolysis of the substrates below 3.8 M hydroperchloric acid media occurs through A-1 type reaction($3.3 >{\omega},\;0.58 >{\phi} & {\rho}< 0$) mechanism and above 3.8 M hydroperchloric acid, the reaction proceeds A-2 type reaction($0 <(\omega)$, $0 <{\phi} & (\rho)> 0$) mechanism.