• Journal of the Korean GEO-environmental Society
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• v.15 no.10
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• pp.15-21
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• 2014

In this study, biochemical methane potential test was conducted to estimate ultimate methane and carbon dioxide yield for anaerobic digestion and pretreatment with sewage sludge cake. Two of 0.2 % TS of sewage sludge cakes were treated with 5M NaOH or sonication of 0.51 W/mL during 30 min respectively. Another sample was treated simultaneously with NaOH and sonication in same condition. Then, initial soluble COD increased from 33.1 mg/L to 494 mg/L. After BMP test, methane production ranged from 3.12 and 84.2 mL $CH_4$ per g of Volatile Solid (VS) and 9.2 and 13.5 mL $CO_2$ per g of Volatile Solid (VS) for carbon dioxide. In other tests, injection of nutrient media or sludge supernatant produced 73.1 and 73.8 mL $CH_4$ per g of Volatile Solid (VS) and 11.2 and 13.6 mL $CO_2$ per g of Volatile Solid (VS) respectively. When BMP test finished, 62 % of initial volatile solids decreased to 33.8~45.4 %. Simultaneous pretreatment increased soluble COD, reduction rate of volatile solids and digestion efficiency than those for alkaline and ultrasonic pretreatment.

• Journal of Mushroom
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• v.14 no.2
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• pp.70-74
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• 2016

A new method to utilize spent mushroom substrates (SMS) for ethanol production was investigated. Analysis of the chemical properties of SMS revealed that they were decomposed by the mushrooms during cultivation. In particular, the free sugar content in SMS was reduced to half of that in mushrooms. Of the tested SMS, the Pleurotus eryngii SMS was determined to be suitable for saccharification. Upon pretreatment with a 1% alkaline solution, Pleurotus eryngii SMS achieved 80.7% of its maximum saccharification ratio. The optimum pretreatment conditions for enzyme saccharification were 1% NaOH solution at $120^{\circ}$ for 60 min. Further studies are required to determine ethanol production using Pleurotus eryngii SMS.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.448-451
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• 2012

본 연구에서 matrix간의 계면 결합력을 불리하게 작용하는 Wax성분이나 Lignin, Hemi-Cellulose등의 제거를 위해 화학적 개질방법중인 NaOH, Acetic acid, Silane으로 처리하여 기질 고분자의 계면의 영향을 알아보고 SEM을 이용하여 형태학적 변화와 열적특성 변화를 관찰하였다. 형태학적 변화에서는 NaOH, Acetic acid 처리보다 Silane처리가 계면결합력이 증가하여 기계적 물성이 증가되었다는 것을 볼수 있었고, 열분석에서는 NaOH, Acetic acid, Silanec 처리가 유사하게 나타났지만, 복합재를 전처리하지 않은것보다 기질고분자와 천연섬유간의 계면 결합은 전처리하는 것이 결합에 있어서 좋다는 결과를 확인하였다.

• Analytical Science and Technology
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• v.12 no.5
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• pp.447-459
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• 1999

A study was conducted to compare three analytical methods for determination of hexavalent chromium in the welding fume. Precision and accuracy arc documented for colorimetric, ion chromatographic, and inductively coupled plasma-optical emission spectroscopic method. Evidence is presented that welding fume can affect the oxidation of trivalent chromium. A simple sonication extraction method, proposed in this study, instead of hot alkaline extraction has the advantage of minimizing the potential for chromium oxidation.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.220-227
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• 2004

This study showed that thermophilic anaerobic acid fermentation of food wastes had an enhanced hydrolysis capability and improvement of acidification efficiency. Influence of pH on the anaerobic hydrolysis and acidogenesis was investigated to determine the proper alkalinity in the thermophilic fermentation of food wastes. The results of putting NaOH as alkali to evaluate hydrolysis and acid fermentation efficiency In acid fermentation process of food wastes showed that the food wastes pretreated with 0.05 g NaOH/g TS had the maximum 12,600 mg/L of VFAs concentration during HRT 3 days in $55^{\circ}C$ thermophilic condition and the maximum 9,700 mg/L of VFAs concentration during HRT 5 days in $35^{\circ}C$ mesophilic condition. The accomplishment of high VFAs concentration resulted from that the main component of food wastes such as cellulose, lignin and etc. is performed active chemical decomposition by alkali in thermophilic condition. The major components of VFAs produced from the thermophilic acid fermentation process of food wastes were the short chain fatty acids such as acetic acid, butyric acid, and propionic acid.

• Fashion & Textile Research Journal
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• v.6 no.3
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• pp.393-398
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• 2004

This research offers recycling method of NaOH from mercerizing process of cotton fabric. The measuring system of NaOH concentration was designed for the mercerizing process and tested for various conditions which can be occurred in factory. The accuracy of the system was varied as the testing condition was changed. As the concentration of sulfuric acid used for titrating NaOH decreased, the accuracy of measuring system increased. The concentration of NaOH for waste water collected from mercerizing process was measured by 5.2%. As the ratio of newly mixed NaOH increased, moisture regain. water absorbency and whiteness of the specimen increased. The bending rigidity(B) and shear rigidity(G) decreased, as the ratio of newly mixed NaOH increased.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.20-27
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• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.8
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• pp.1323-1332
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• 2006

Lyocell is a regenerated cellulose fiber manufactured by an environmentally-friendly process. Since the fiber has more crystalline region compared to rayon, lyocell shows higher wet-strength than rayon. Although fibril generation of lyocell is lower than that of rayon because of the reason, the fibril generated during the wet process deteriorates the smooth look and soft touch of the fabric. The efficient way to remove the fibril yet retain the strength property was investigated in this work. In order to scour and remove the fibril from the fabric, cellulase enzymes were introduced and the traditional scouring was carried to be compared. Weight loss, dye-ability, and strength of treated fabric were measured after the treatments. Scanning electron microscopy was used to observe the surface of the fiber. Among the cellulases used in this work, Denimax 992L showed the best results for removal of fibril with low weight loss and tensile strength loss. The optimal conditions for the enzymatic treatment could be chosen depending on a characteristic for final purpose of the lyocell product.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.255-264
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• 2009

To evaluate the effects of chemical pretreatments of lignocellulosic biomass on enzymatic hydrolysis process, Populus euramericana was pretreated for 1 hr with 1% sulfuric acid ($H_2SO_4$) at $150^{\circ}C$ and 1% sodium hydroxide (NaOH) at $160^{\circ}C$, respectively. Before the enzymatic hydrolysis, each pretreated sample was subjected to drying process and thus finally divided into four subgroups; dried or non-dried acid pretreated samples and dried or non-dried alkali pretreated samples and chemical and physical properties of them were analyzed. Biomass degradation by acid pretreatment was determined to 6% higher compared to alkali pretreatment. By the action of acid ca. 24.5% of biomass was dissolved into solution, while alkali degraded ca. 18.6% of biomass. However, reverse results were observed in delignification rates, in which alkali pretreatment released 2% more lignin fragment from biomass to the solution than acid pretreatment. Unexpectedly, samples after both pretreatments were determined to somewhat higher crystallinity than untreated samples. This result may be explained by selective disrupture of amorphous region in cellulose during pretreatments, thus the cellulose crystallinity seems to be accumulated in the pretreated samples. SEM images revealed that pretreated samples showed relative rough and partly cracked surfaces due to the decomposition of components, but the image of acid pretreated samples which were dried was similar to that of the control. In pore size distribution, dried acid pretreated samples were similar to the control, while that in alkali pretreated samples was gradually increased as pore diameter increased. The pore volume which increased by acid pretreatment rapidly decreased by drying process. Alkali pretreatment was much more effective on enzymatic digestibility than acid pretreatment. The sample after alkali pretreatment was enzymatically hydrolyzed up to 45.8%, while only 26.9% of acid pretreated sample was digested at the same condition. The high digestibility of the sample was also influenced to the yields of monomeric sugars during enzymatic hydrolysis. In addition, drying process of pretreated samples affected detrimentally not only to digestibility but also to the yields of monomeric sugars.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.58-64
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• 2009

This study was carried out to prepare high porosity pulp for oil and air filter media from commercial grade NBKP with 6 - 20% NaOH treatment. The fiber width of NBKP remarkably decreased by NaOH pretreatment. The air permeability of the test sheet prepared from alkali-pretreated NBKP increased with increasing NaOH concentration up to 15%. The burst factor was greatly decreased by alkali pretreatment. By 15 - 20% NaOH pretreatment of NBKP, it could be possible to prepare a high porosity pulp. It seems that the high porosity of the pulp was due to a strong swelling and a great change of the cellulose crystalline lattice from cellulose I to cellulose II with NaOH treatment of NBKP. The study suggested that alkali- pretreated NBKP could be used for manufacturing oil and air filter media.