• Journal of the Korean Wood Science and Technology
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• 제25권2호
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• pp.100-109
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• 1997

The objectives of this study was to decrease pollutions of bleaching effluent and was to enhanced brightness of non-chlorine bleached pulps by xylanase treatments. Xylanase cloned Esherichacoli(E. coli) capable of each of endo, exo-xylanase and acetyl-esterase were obtained from Bacillus stearothermophillus. These xylanase was maintained high activity in alkali and high temperature. Especially endo-xylanase would be more active in $60^{\circ}C$ and pH 11. Xylanase pretreatment(X) of unbleached pulp increased brightness, and decreased the degree of delignification. The degree of increase in brightness of pulp due to xylanase pretreatment was similar to non-enzyme treated pulp, regardless of the amount of enzyme added. Therefore, the addition of xylanase of 2 unit was recommended when considering costs of enzyme. The pulp bleached XO sequence had higher brightness and lower Kappa no, than O bleached pulp, while pulp bleached XP sequence had similar brightness and Kappa no. with P bleached pulp. In XOC/D, XOZ and XOP bleaching sequences, brightness and degree of delignification were improved. The C/D and Z stage bleached pulp was good effect on rate of raise in brightness and Kappa no., but P stage bleached pulp had similar level in non-enzyme treated bleaching sequence.

• 펄프종이기술
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• 제47권3호
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• pp.47-54
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• 2015

In this study, effects of kneading treatment on the properties of hardwood bleached kraft pulp (HwBKP), softwood bleached kraft pulp (SwBKP) and hardwood bleached chemi-thermo-mechanical pulp (HwBCTMP) were elucidated with a laboratory two-shaft kneader. Kneading treatment was performed at 30% (w/w) of pulp concentration and the number of passes through the kneader was adjusted from 0 to 10 passes. Then, changes in properties of pulp fibers were evaluated. It was found that fiber characteristics were influenced by kneading treatment. Fiber length was decreased with kneading while other morphological properties such as fiber width, curl and kink became increased as the number of passes through the kneader increased from 0 to 5 passes. The magnitude of changes in the morphological properties of softwood chemical pulp was the largest, followed by hardwood chemical pulp. The morphological properties of HwBCTMP were little influenced by kneading treatment. Swelling of fiber measured by WRV was increased with kneading except of HwBCTMP.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.169-169
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• 2011

Xylans are polysaccharides present in large amounts in cell walls of land plants. However, during kraft cooking, a high portion of hemicelluloses including xylans are dissolved in the cooking liquor. In the current trend for a more effective utilization of biomass, attention has been paid to the exploitation of xylans as strength-enhancing additives for paper. It is believed that surface xylan adds flexibility to the cell wall/fiber surface, resulting in stronger fiber-fiber joints or greater contact area between the fibers. Accordingly, there is proposal for a new pulping process involving the extraction of xylan prior to pulping, followed by their re-adsorption on the unbleached pulp. A suitable bleaching process should be employed then, which ought to does not only improve the brightness of the pulp, but also remain the effect of the adsorption of xylan on pulp fibers. The objective of this research was to investigate the impact of hydrogen peroxide bleaching on the properties of unbleached hardwood kraft pulp pretreated with birchwood xylan by measuring optical properties (brightness, post color number, opacity) as well as physical properties (tensile index, tearing index, bulk) of handsheets made from the bleached pulp. In the meantime, the influence of process variables of peroxide bleaching including bleaching temperature, time, initial pH and $MgSO_4$ dosage were studied.

• Journal of the Korean Wood Science and Technology
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• 제32권3호
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• pp.52-58
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• 2004

The use of N-hydroxyphthalimide (NHPI) as a mediator for laccase has proven to be comparable to N-hydroxybenzotriazole (HBT) for the delignification of kraft pulp, and the transformation of a number of industrial dyes. The advantages of NHPI derivatives are the biodegradation of these compounds compared to HBT, which has been shown to be recalcitrant in the environment, and the more reasonable cost of synthetic process.

• 펄프종이기술
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• 제36권5호
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• pp.62-68
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• 2004

The amount of non-lignin components in unbleached and oxygen-delignified kraft pulps and their impact on lignin determinations was investigated. The lignin analyses investigated were kappa number and Klason lignin in conjunction with acid-soluble lignin. The species investigated were loblolly pine, and aspen. The non-lignin components that impacted on lignin determination were residual extractives and hexenuronic acid in unbleached and oxygen-delignified kraft pulps. In the hardwoods, significant amounts of extractives remained after kraft pulping and oxygen delignification. These residual extractives in the hardwood pulps had an impact on the lignin determination, more so on the acid lignin method than kappa number. Hexenuronic acid only impacts on kappa number determination both softwood and hardwood pulps, not on acid lignin. Hexeneuronic acid contributed as lignin content more in aspen than pine pulps, and more in oxygen-delignified than unbleached kraft pulps. Impact of hexenuronic acid on should be corrected both softwood and hardwood pulps for accurate kappa number.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.279-284
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• 2006

Activated carbon is proposed as a new application of wastepaper recycling other than the paper-making. Waste kraft bag is considered to be a suitable raw material for activated carbon because of its low ash content. Small pellets of wastepaper squeezed out from the continuous kneader were carbonized in a nitrogen atmosphere and activated using carbon dioxide. The BET specific surface areas of activated carbon prepared from waste kraft bag was $1,285m^{2}/g$, which is higher than commercially available activated carbons. The activated carbon prepared from wastepaper has a well-developed porous structure, particularly in mesopore and macropore ranges. As a result, activated carbon with iodine adsorption capacity of 1,400 mg/g was obtained from waste kraft bag. In this paper, adsorption amount of Bisphenol A (BPA) was determined to investigate adsorbability of activated carbon from waste kraft bag. Adsorption measurements were on solutions ranging from $0.1{mu}g/L\;to\;100mg/L$. The activated carbon from waste kraft bag gave higher BPA adsorbabilities over a wide range, compared with commercially available activated carbons.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.566-577
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• 2015

White Jabon (Anthocephalus cadamba Miq.) is one of the fast growing species in Indonesia and has the potential as the raw material for pulp and paper. In this research, 3, 5, and 7 years old White Jabon woods were pulped under different active alkali charge of 15%, 18%, 21%, 24%, and 27%, and its effect on delignification degree, kappa number, pulp yield, pulp viscosity, brightness, unbeaten freeness, and delignification selectivity was investigated. The results showed that tree age and active alkali concentration influenced the quality of pulp and pulping properties, except for that of unbeaten freeness. Delignification degree increased with increasing active alkali charge, and this brought about the decrease of pulp kappa number. The pulping yield tended to decrease below the Klason lignin of approximately 4%. Even though the 3 years old wood resulted in the highest brightness and highest delignification selectivity, the highest pulp viscosity was obtained with the 5 years old wood. The dominant fiber length of all wood ages was in the range of 1.2 - 2.0 mm. The 3 years old wood was considered to be the most promising raw material for kraft pulping in the view point of pulping properties, pulp quality and harvesting rotation.

• 펄프종이기술
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• 제46권5호
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• pp.43-50
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• 2014

The cultivation of agricultural crops results in the generation of agricultural byproducts. Researchers have reported that these materials can be useful in a variety of applications. However, over 50% of them are currently discarded because of the lack of specific technologies in industrial applications. Therefore, effective and specific applications must be developed in order to manufacture high-quality materials using discarded lignocellulosic resources. In this study, we determined the possibility of using kraft pulp from major agricultural byproducts as a raw material for the manufacture of paperboard. Rice husks, peanut husks, and garlic stems were obtained and used to prepare many kinds of kraft pulps by controlling the active alkali, sulfidity, reaction time, and liquor ratio. After the production of these kraft pulps, handsheets were manufactured by mixing them with KOCC. After preconditioning, the physical properties and strengths of the handsheets were measured according to the TAPPI test methods. The shapes, lengths, and widths of the pulp fibers varied according to the type of agricultural byproduct and the kraft pulping conditions. Rice husk and garlic stem pulps manufactured under mild pulping conditions resulted in handsheets of higher bulk than other pulps. Garlic stem pulps manufactured under mild pulping conditions were stronger than rice husk pulps and peanut husk pulps.

• 한국인쇄학회지
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• 제19권1호
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• pp.64-74
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• 2001

This study is to find the effect of the molecular weight distribution of components on the freeness and physical properties of paper by observing the change of properties according the modification of fibers by using production technology and process technology together to develop additives which can effectively control according to the purpose of paper-making process and by combining low molecular weight cellulase (below MW 20,000; CMC activity 400 unit) with different enzyme's molecular weight and activity and high molecular weight cellulase(MW 20,000∼80,000;CMC activity 90,000 unit) and then process them in Sw-BKP(Softwood Bleached Kraft Pulp) and Hw-BKP(Hardwood Bleached Kraft Pulp) and Cotton Linter Pulp and OCC(Old Corrugated Container) with different properties of pore of surface of fibers respectively, since it is judged that making the appropriate composition ratio of components is necessary in consideration of the properties of fibers and paper-making process.

• 환경생물
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• 제17권2호
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• pp.191-198
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• 1999

침엽수와 활엽수 펄프내의 리그닌(lignin) 제거 효과를 개선하기 위해 호알칼리성 균류인 Cephalospotium sp. RYM-202의 xylanase를 표백 전처리하고 이에 의한 펄프의 표백 증진 효과를 조사하였다. 두 종류의 펄프 모두 5$0^{\circ}C$에서 효소반응을 수행하였을 때 펄프내 xylan의 가수분해가 가장 높게 나타났다. 펄프내 xylan의 가수분해를 위한 효소의 최적 pH는 8.0이었으며, pH 9.0에서도 최대활성의 90%이상이 유지되었다. 각각의 펄프 재료에 효소를 전처리한 결과 표백(리그닌 제거)과정의 증진 효과를 보였으며, 침엽수와 활엽수의 kappa number는 각각 3.7과 2.0 ISO units 만큼 감소되었다. 아울러 효소처리 혹은 효소 미처리 펄프를 각각 표백한 후 수초지를 제조하여 종이의 물성을 상호 비교한 바, 효소처리는 종이의 섬유 구조에 큰 영향을 끼치지 않는 것으로 나타났다. 이러한 결과들은 호알칼리성 Cephalospotium sp. RYM-202의 알칼리내성 xylanase가 알칼리 조건하에서의 펄프 전처리 과정에 매우 적합함을 의미한다.