• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.101-110
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• 2011

The experiment was conducted to evaluate the different NaOH pretreatment concentrations (0.25%, 0.50%, 0.75%, and 1.00%) on enzymatic saccharification (with cellulase, and ${\beta}$-glucosidase) and fermentation (by Saccharomyces cerevisiaeKCCM 11304) for bioethanol production from rice straw and rice husk. Pretreatment of rice straw and rice husk were conducted under both natural and powder state to observe the potentiality of the biomass condition (natural and powder state). In this study, glucose and ethanol production were increased with the increase of NaOH percentage for both rice straw and rice husk (natural and powder state). For rice straw, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.81 g $g^{-1}$ in a natural, and 0.63 g $g^{-1}$ in a powder state pretreatment). Similarly, for rice husk, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.47 g $g^{-1}$ in a natural, and 0.46 g $g^{-1}$ in a powder state pretreatment). However, 0.75% NaOH pretreatment resulted in glucose yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). On the other hand, for rice straw, the highest amount of ethanol was obtained in 1.00% NaOH pretreatment (0.36 g $g^{-1}$ in a natural, and 0.31 g $g^{-1}$ in a powder state pretreatment). In addition, for rice husk, the highest amount of ethanol was also obtained in 1.00% NaOH pretreatment (0.24 g $g^{-1}$ in a natural, and 0.23 g $g^{-1}$ in a powder state pretreatment). Moreover, 0.75% NaOH pretreatment resulted in ethanol yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). It was confirmed that higher amount of NaOH use is cost effective. Moreover, higher amount of glucose and ethanol was observed when powder was prepared after pretreatment. So 0.75% NaOH pretreatment in a natural state is supposed to be suitable for enzymatic saccharification and fermentation for bioethanol production.

• Textile Coloration and Finishing
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• v.15 no.4
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• pp.39-42
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• 2003

Automatic concentration control system for pretreatment of dyeing was set up with adaptive control system supported by Fuzzy logic for the high speed successive pretreatment of fabric. Concentration of pretreatment bath was determined by the conductivity due to the ionized NaOH. Usability of this system was also evaluated with 30wt% of NaOH (conductivity of 0.25 S/cm) as an initial concentration. Conductivity fluctuated between 0.31 and 0.17 S/cm. This range accorded with the 21-35wt% of NaOH concentration.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.4
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• pp.1-7
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• 2003

In this study, fiber mechanical pretreatment before refining was executed with the addition of papermaking addiditives to find synergistic effects on fiber property improvement. Three fiber furnishes (SwBKP, KOCC, and BCTMP), and five different additives (CMC, CPAM, PEO, NaOH, $Na_2O_2$) were used. It was confirmed again that fiber mechanical pretreatment using Hobart mixer was a special way to modify fiber properties, where fiber WRV (water retention value) increases without losing fiber length. For SwBKP, addition of small amount of CMC (0.2％ OD basis), and for KOCC, PEO (0.2％ OD basis) caused additional significant improvement of the fiber furnish properties, respectively. Other additives did not cause adverse effects on the mechanical pretreatment, or better. For BCTMP, NaOH addition followed by mechanical pretreatment caused more than 20％ improvement in tensile and tear strength simultaneously, compared to the control. The yellowing caused by the treatment of NaOH on BCTMP could be minimized by using $Na_2O_2$ without losing the positive effect of NaOH.

• 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.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.265-272
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• 2023

Lignocellulosic biomass is essential to pretreatment because of having rigid structures and a lot of lignin. Among methods of pretreatment, using THF solvents has the advantage of being easy to reuse. THF (Tetrahydrofuran) used as a co-solvent with water or ionic solvent that is inexpensive and can remove lignin over a wide range of reaction conditions. NaOH (Sodium hydroxide) has been demonstrated to preferentially solvate lignin from cellulose. Thus, NaOH was used as a pretreatment co-solvent for the fractionation of lignin by destroying the ether bond to amend for hydrolysis and expand the surface area of cellulose and hemicellulose. In this experiment, lignin was removed by the NaOH/THF co-solvent pretreatment process to characteristics for the pretreatment and obtain the optimal levulinic acid conversion yield through the acid catalyst conversion process. the NaOH/THF co-solvent system was conducted in various ratios of co-solvent under a total of 16 conditions. And the temperature was 180 ℃ during to 60 mins. The optimum condition of co-solvent is NaOH 5 wt%/THF 90:10(v/v%), 76.8% glucan content was obtained through this co-solvent pretreatment, and 90.1% lignin was removed. In the acid catalyst conversion process, which is a subsequent pretreatment process, the experiment was conducted under the conditions of 30 to 90 min of reaction time and 160 ℃ to 200 ℃ reaction temperature. The optimum condition of acid catalyst conversion process is 60min reaction time under of 180 ℃, and it obtained 84.7% of levulinic aicd conversion yield.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.1-7
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• 2014

Dissolving part of xylan and lignin in lignocellulosic biomass by base can be used as pretreatment technique. Cork oak was pretreated with sodium hydroxide solution and the pretreatment effects were evaluated with two critical factors - NaOH concentration and pretreatment temperature. Some of xylan and lignin were removed by base pretreatment. At $90^{\circ}C$ and 13% NaOH pretreatment, 22.0% of lignin and 78.8% of xylan removed by base treatment. Enzymatic hydrolysis of cork oak which was pretreated at higher temperature or concentration was further improved. After pretreatment of cork oak with 13% NaOH at $90^{\circ}C$, the conversion rate of cellulose to fermentable sugars were reached up to 91.3%. At ethanol fermentation with enzymatic hydrolysate from different pretreatment conditions, all enzymatic saccharification liquids were well fermented by Saccharomyces cerevisiae.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2413-2420
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• 2018

Sida acuta, a common type of weed in Thailand, contains relatively high cellulose (42.7%) content. We pretreated NaOH to improve glucose recovery from S. acuta. The effect of pretreatment temperature and NaOH concentration was fundamentally investigated based on hydrolysis efficiency with recovery of solid fraction. The pretreatment condition was determined to be 3% NaOH at $60^{\circ}C$ for 9 h, which showed the highest glucose recovery. The hydrolysates obtained by enzymatic hydrolysis of S. acuta were applied to the fermentation of Saccharomyces cerevisiae K35, and a theoretical yield of 97.6% was achieved at 18 h. This indicated that the hydrolysates medium without detoxification had no negative effects on the fermentation. The production of biomass into bioethanol was evaluated based on the material balance of 1,000 g basis. Following this estimation, approximately 28 g and 110 g bioethanol could be produced by untreated and pretreated S. acuta, respectively, and this production was improved about 3.9-fold by NaOH pretreatment. These results again show the importance of pretreatment in biorefinery process.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.106.1-106.1
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• 2010

본 연구는 팜 부산물로부터 바이오 에탄올을 생산하는 전처리-당화-발효 공정의 첫 번째 단계인 전처리 공정에서 팜 부산물을 NaOH를 이용하여 효율적으로 전처리하고자 하였다. 암모니아 침지법과 NaOH 침출법을 비교한 결과 팜 부산물에 대해서는 암모니아 침지에 의한 탈리그닌 효과가 적으며 NaOH 전처리가 적합한 방법임을 알 수 있었다. 40-100 mesh 크기의 팜 부산물을 이용하여 반응온도(110, 130, $150^{\circ}C$), 반응시간(20, 40, 60분) 및 NaOH 농도(5%, 11%)의 변화에 따른 팜 부산물의 탈리그닌율과 글루코스 및 자일로스 회수율 간의 상호관계를 확인하였다. $150^{\circ}C$까지의 온도 조건에서 온도에 의한 자일로스의 분해는 일어나지 않는 것으로 확인되었다. 팜 부산물의 탈리그닌율은 시간이 증가할수록 증가하였으며, 높은 NaOH 농도에서 더 높은 것으로 나타났다. 그러나 글루코스 및 자일로스의 회수율은 높은 농도에서 낮게 나타났으며, 시간이 지날수록 감소하여 손실이 많은 것으로 나타났다. 따라서 NaOH 농도가 낮을수록 당 회수율은 높게 나타나지만, 탈리그닌율이 낮아 당화 효율이 떨어지므로 효소 당화 후에 최종 당 회수율이 높은 NaOH 농도 조건을 결정하여야 하겠다.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.431-435
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• 2016

The aim of this study was to investigate the effect of gamma irradiation on the pretreatment of wood chips with NaOH solution. The degree of saccharification was quantified by measuring reducing sugar and glucose concentrations after enzymatic hydrolysis. After pretreatment with 10 g/L NaOH, the wood chips were irradiated at the doses of 0, 50, 100, and 200 kGy, respectively. Among the irradiated samples, wood chips irradiated at the dose of 200 kGy had the highest reducing sugar concentration of 12.2 g/L. Also, to define the effect of irradiation before pretreatment, the wood chips were first gamma-irradiated and then pretreated with NaOH. When the NaOH treatment was conducted after irradiation at 200 kGy, the reducing sugar content was further increased to 13.4 g/L and glucose content of the wood chip was as high as 7.9 g/L. These results suggest that gamma irradiation may be the promising method for pretreatment of cellulose biomass.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.121-129
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• 2024

The study investigated the effect of thermo-alkaline pretreatment on the solubilization of polyhydroxybutyrate (PHB) and its potential to enhance of thermophilic anaerobic digestion, focusing on biochemical methane potential (BMP) and methane production rate, using two different particle sizes of PHB (1500 ㎛ and 400 ㎛). Thermo-alkaline pretreatment tests were conducted at 90 ℃ for 24 hours with varying NaOH dosages from 0-80% (w/w). BMP tests with untreated PHB exhibited methane production ranging from 150.4~225.4 mL CH₄/g COD and 21.5~24.2 mL CH₄/g VSS/d, indicating higher methane production for smaller particle sizes of PHB, 400 ㎛. Thermo-alkaline pretreatment tests achieved a 95.3% PHB solubilization efficiency when 400 ㎛ PHB particles were treated with 80% NaOH dosage at 90 ℃ for 24 hours. BMP tests with pretreated PHB showed substantial improvement in thermophilic anaerobic digestion, with an increase of up to 112% in BMP and up to 168% in methane production rate. The results suggest that a combined pretreatment process, including physical (400 ㎛ PHB particles) and thermo-alkaline (90 ℃, 40-80% NaOH dosage, and 24 hours reaction time), is required for high-rate thermophilic anaerobic digestion of PHB with enhanced methane production.