• 상하수도학회지
• /
• 제17권4호
• /
• pp.559-566
• /
• 2003

From this research, the performances of a sludge reduction in the sewage sludge aerobic digestion was experimented by using a sludge pretreatment and membrane bioreactor. The submerged plate membrane was used as the solid-liquid separation membrane. After drawing small amounts of sludge in a bioreactor and then doing the alkaline treatment and ozone treatment, the sludge was sent to back to the reactor. The HRT in the reactor was set as 5 days and the operation in the reactor was carried out at the DO of 1mg/L on average. After 100 days of operation in the reactor, it was shown that the reduction efficiency of total solids was more than 83%. Most of volatile solids were removed through mineralization, and the considerable portion of the non-volatile solids was dissolved and then flowed out with the effluent. Only about 16.3% of total solids in the sludge was accmulated in the reactor even without the loss of volatile fraction. Also, by deriving nitrification and denitrification in one reactor simultaneously, more than 90% of nitrogen removal effect was realized and the experiment was run smoothly without fouling of membrane, even in the high concentration of MLSS. Based on this experiment, sludge can be reduced considerably at a low HRT by these two newly suggested approach.

• 한국수소및신에너지학회논문집
• /
• 제2권1호
• /
• pp.57-67
• /
• 1990

This study is proposed to investigate the effect of electrode preparation method for Alkaline Fuel Cell using NaOH as an electrolyte on the Fuel Cell performance. The materials used for the preparation of electrode are Pt and Ag on Vulcan XC-72. Surface area of Vulcan XC-72 have different values according to the pretreatment conditions and the dispersion of Pt is dependent on the impregnation Particle size of Pt impregnated on unpretreated carbon was observed to be $20{\sim}40{\AA}$ and that on pretreated carbon in $N_2$ stream at $950^{\circ}C$ was found to be finely dispersed less then $15{\AA}$. The electrode performance was affected by the particle size of metals and operating temperature. It was revealed from this study that the optimum particle size about $30{\AA}$ and optimum temperature range is between $90{\sim}100^{\circ}C$.

• Journal of the Korean Wood Science and Technology
• /
• 제22권3호
• /
• pp.32-38
• /
• 1994

The methods in wood processing are so limited at present that a scope of its utilization is restricted. This often makes wood itself less valuable as a material comparing with other materials, that is, plastics, metals, and glass. Such differences are due to a lack of plasticity in wood, i.e. it cannot be melted, dissolved, or softened sufficiently for molding. However, once plastic properties are added to wood, it becomes more useful material. This further broadens the method in wood processing to a variety of fields. In this way, wooden material which is limited in use can be modified into a high quality product with additional value. Furthermore, utilization of wastes from wood, for example, would be made viable. In this study, thermoplasticization was carried out by benzylation of wood(sawdust). Various factors those affect the reaction were tested to produce benzylated wood with different degrees of substitution. Reaction temperature and time were the quite important factors. Optimum reaction temperature was 110$^{\circ}C$, and weight percent gains(WPG) of final products increased gradually with the increase of reaction time. The pretreatment (or preswelling) of wood with alkaline solution had a critical effect on benzylation. and the concentration of alkaline solution should be above 30% to obtain high weight percent gain. The thermal flow temperature of the benzylated wood decreased with the increase in weight percent gain, that of 80% weight percent gain is about 200$^{\circ}C$.

• 한국버섯학회지
• /
• 제14권2호
• /
• pp.70-74
• /
• 2016

본 연구에서는 버섯 수확후배지를 바이오매스로 활용하고자 수행하였으며, 적정 전처리 조건을 구명한 결과는 다음과 같다. 버섯 수확후 배지의 전처리방법 중 알카리 처리가 리그닌 함량을 효과적으로 경감시키면서, 당전환율이 우수하였고 큰느타리 수확후 배지가 당전환율 80.7%로 가장 우수하였다. 큰느타리 수확후 배지에 1% NaOH를 이용한 알카리 처리시 전처리 온도별 성분분석 결과 $120^{\circ}C$처리시에 glucose 25.3%, xylose 14.8%로 유리당 함량이 가장 높고, 효소에 의한 당전환율도 66%로 무처리구 28.2%에 비해 2.3배 증가되었다. 촉매제 농도(NaOH 0.5~2.0%)에 따른 당분석결과 glucose 함량은 촉매제 농도와 관계가 적었으며, xylose와 arabinose는 촉매제 농도가 높을수록 다소 감소하는 경향이었다. 그러나 당전환율은 NaOH 1% 처리시에 66%로 가장 높았다.

• Journal of Acupuncture Research
• /
• 제23권2호
• /
• pp.103-111
• /
• 2006

Objectives : Deer antler Water Extract(DAE), prepared from the pilose antler of Cervus korean TEMMINCK var. mantchuricus Swinhoe (Nokyong), a traditional immuno-suppressive and immuno-activating Korean herbal-acupuncture, is thought to play an important role in human bone remodeling. Methods : To determine whether DAE can induce the differentiation of resting zone chondrocytes(RC) or not, confluent cell cultures were pretreated for 24, 36, 48, 72, and 120hrs with DAE. At the end of pretreatment, the media were replaced with new media containing $10^{-10}{\sim}10^{-8}M\;1,25-(OH)_2D_3$ and the cells incubated for an additional 24hrs. Results : This second treatment was chosen because prior studies had shown that only the more mature growth zone chondrocytes(GC) respond to this vitamin $D_3$ metabolite. The effect of DAE pretreatment on cell maturation was confirmed by measuring alkaline phosphatase (ALPase)-specific activity. Changes in matrix protein synthesis were examined by measuring collagen synthesis, as well as $^{35}SO_4$ incorporation into proteoglycans. When RC cells were pretreated for 120h with DAE, treatment with $1,25-(OH)_2D_3$ caused a dose-dependent increase in ALPase-specific activity and collagen synthesis, however, the proteoglycan production was not affected. RC cells pretreated with $1,25-(OH)_2D_3$ responded like RC cells that had not received any pretreatment. Conclusion : These results indicate that DAE directly regulates the maturation of RC chondrocytes into GC chondrocytes. Therefore it was indicated that DAE may play a significant role in regulating chondrocyte maturation during endochondral ossification.

• Korean Journal of Chemical Engineering
• /
• 제35권12호
• /
• pp.2403-2412
• /
• 2018

The present study was aimed at evaluating the effect of variable sodium carbonate ($Na_2CO_3$) loading during wet air oxidation (WAO) pretreatment of rice straw in reducing biomass recalcitrance. The research study was intended to increase the cellulose recovery, hemicellulose solubilization, lignin removal in the solid fraction and limiting the generation of inhibitors in the liquid fraction while reducing the chemical input. The operating condition of $169^{\circ}C$, 4 bar, 18 min and 6.5 g/L $Na_2CO_3$ loading resulted in maximum cellulose recovery of 82.07% and hemicellulose solubilization and lignin removal of 85.43% and 65.42%, respectively, with a total phenolic content of 0.36 g/L in the liquid fraction. The crystallinity index increased from 47.69 to 51.25 along with enzymatic digestibility with an increase in $Na_2CO_3$ loading from 0 to 6.5 g/L as a result of removal of barriers for saccharification via effective cleavage of ether and ester bonds cross-linking the carbohydrates and lignin as indicated by FT-IR spectroscopy. A further increase in the $Na_2CO_3$ loading to 9.5 g/L did not significantly increase the sugar release. Thus, it was concluded that 6.5 g/L $Na_2CO_3$ during WAO is sufficient to increase the delignification and deacetylation, leading to significant changes in apparent cellulose crystallinity inter alia improvement in cellulose accessibility and digestibility of rice straw.

• 분석과학
• /
• 제37권3호
• /
• pp.174-188
• /
• 2024

본 연구에서는 토양 및 지하수 중 미세플라스틱(MP) 분석법 표준화를 위해 관련 국내·외 연구동향을 검토하고 매체 별 시료채취 방법, 전처리 방법 및 분석 장치의 종류 등에 관한 대표적인 방법을 리뷰하였다. 토양 시료채취는 시료채취 지점선정, 채취 깊이 및 시료량을 고려하고 있으며 대부분 15 cm 이내(표토) 깊이에서 약 1 kg의 시료를 혼합채취하는 것으로 파악되었다. 지하수 시료채취는 정치방법과 연속흐름방법 중 연속흐름방식이 대표적이고 채취량 300~1,000 L 구간에서 유량 2~6 L/min로 채취하며 현장 여과하였다. 처리 방법은 두 매체에 공통적으로 유기물 분해와 밀도차 분리로 나뉘며 유기물 분해방법인 H₂O₂, 산, 알칼리, 효소 활용 중 H₂O₂가 추천된다. 밀도 분리는 NaCl, ZnCl₂, ZnBr₂ 등의 시약 중 NaCl이 주로 사용되나 분석하고자 하는 MP의 밀도에 따라 시약을 선택적으로 활용할 수 있다. 분석 기기는 비파괴적 분석법인 FTIR, Raman과 파괴 분석법인 Py-GC/MS가 대표적이다. µ-FTIR은 직경 10 ㎛ 이상 Raman은 1 ㎛ 이상의 MP 재질과 개수 분석이 가능하나 전처리를 통해 유기물과 같은 분광분석의 방해요소를 충분히 제거해야 한다. Py-GC/MS는 복잡한 전처리가 필요 없고 특정 재질의 정량분석이 가능하여 지속적으로 연구되어지고 있다.

• 한국균학회지
• /
• 제16권3호
• /
• pp.135-143
• /
• 1988

볏짚의 $H_2O_2$ 처리는 첨가농도를 늘리거나 pH를 알칼리로 조정하는 것이 첨가비율을 증가시키는 것 보다 비소화성 물질의 분해에 효과적이었고 볏짚입자가 작을수록 이러한 효과는 현저하였다. $2Na_2CO_3{\cdot}3H_2O_2$는 pH를 조정할 필요는 없으나 처리효과는 pH를 11.5로 조정한 $H_2O_2$ 처리에 비하여 낮았다. Alkaline peroxide 처리에 의하여 lignin과 hemicellulose의 감소는 현저하였다. Alkaline peroxide 전처리 볏짚의 발효로 총질소와회분은 증가하였고, NDF, hemicellulose, lignin은 분해되어 감소되었으며, ADF와 cellulose는 저농도 처리에서 감소하였다. 볏짚의 소화율은 alkaline peroxide 처리농도가 증가할수록 향상되어 대조구의 31.0%에 비하여 pH를 11.5로 조정한 12% $H_2O_2$와 12% $2Na_2CO_3{\cdot}3H_2O_2$ 처리시 각각 89.4%, 76.8%로 상승되었다. Alkaline peroxide 전처리 볏짚의 발효에 의한 소화율의 상승은 저농도 전처리에서 효과적이었다. 4% $H_2O_2$ 반건식처리로 ADF와 cellulose는 감소되어 소화율은 57.5%이었고 전처리 볏질의 발효로 대조구의 33.4%에 비하여 63.4%로 상승되었다.

• 한국염색가공학회지
• /
• 제5권3호
• /
• pp.206-215
• /
• 1993

In the prior study, wool gabardines were treated with alkaline proteases which were some kinds of enzyme to decompose protein, and their tensile strengths were determined, and the surface of the fibers were also observed using a scanning electron microscope. Enzylon ASN 30 and Alkalase 2.5L DX did not show much effect on the weight loss of wool, however, the weight loss of wool increased considerably with treating Esperase 8.0L. Pretreatment of wool with dichloloisocyanuric acid before protease-treatment increased the weight loss of wool to a great extent. In this study, the enzyme treated wools dyeing behaviors with acid dye, Milling Cyanine 5R, were mainly investigated. The protease-treatment remarkably increased not only the rate of dyeing but also the saturation dye uptake. From these results, it seemed likely that the structural relaxation of adhesive filler of interscale or intercellular cement facilitated the dye penetration into the fibers, at the same time, the change in the inner structure of the wool fibers by the protease made the fixation of the dyes more efficient.

• 한국수소및신에너지학회논문집
• /
• 제26권1호
• /
• pp.71-78
• /
• 2015

This study was performed to optimize the integrated thermal-alkali pre-treatment of flotation scum for the enhanced biodegradability. The optimum conditions of the integrated thermal-alkali pre-treatment were obtained using response surface methodology. The disintegration degree of carbohydrate (69.2%) and protein (57.3) were estimated under the optimum conditions. Although the optimum conditions were different, the disintegration degrees were similarly. A fermentative hydrogen batch test was conducted to evaluate the hydrogen production from scum with and/or without. The maximum hydrogen production from scum with pre-treatment was of 0.64 mol H2/mol hexoseadded, which about 1.4 times higher than without pre-treatment.