• Journal of the Korean Wood Science and Technology
• /
• 제27권2호
• /
• pp.46-52
• /
• 1999

소나무 수피를 알칼리성 아황산염-안트라퀴논(AQ) 증해하고, 고도로 탐리그닌 시킬 수 있는 조건을 검토하였다. 수피의 탈리그닌은 약알칼리성 아황산염 증해 조건에서보다 알칼성 아황산염 증해 조건에서 용이하였다. 그러나 알칼리성 아황산염 증해조건에서도 수피리그닌의 90%이상을 용출시키기는 어려웠다. AQ는 알칼리성 아황산염 증해 조건에서 수피의 증해 및 탈리그닌 속도를 현저하게 향상 시킬 뿐만 아니라 탈리그닌 선택성도 개선시켰다. 결과적으로 수피에 대하여 0.2% AQ의 첨가로 90%이상의 탈리그닌이 가능하였다. 수피 알칼리성 아황산염-AQ증해시 증해온도 및 NaOH의 투여량은 탈리그닌 선택성에 대해서 큰 영향을 미치지 못하였다. 그러나 $Na_2SO_3$ 투여량은 수피의 탈리그닌 선택성에 큰 영향을 미쳐 $Na_2O$로서 30%의 $Na_2SO_3$ 투여조건에서 가장 양호한 탈리그닌을 나타내었다.

• Journal of the Korean Wood Science and Technology
• /
• 제22권1호
• /
• pp.34-39
• /
• 1994

Effects of Mg-base acid sulfite and Mg- or Na-base bisulfite on pine bark cooking were examined. In the presence of 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid. However, the delignification could not be achieved by 50 % or more under these cooking conditions. When cooked with 50~65 % free acid and at 155~165 $^{\circ}C$, the rate of cooking and delignification was remarkably improved. Thus, the bark was delignified up to 73 % when cooked for 2 hours in the presence of 50 % free acid and 24 % total acid. Na-base bisulfite was slightly more effective than Mg-base bisulfite for cooking, giving 76 % delignification of pine bark. However, there was no significant difference in selectivity of delignification between Na- and Mg-base bisulfite cooking.

• 펄프종이기술
• /
• 제39권5호
• /
• pp.7-11
• /
• 2007

Kraft pulping of Trema orientalis (Nalita) was studied in order to find kinetic data for delignification. Pulping runs were carried out in the temperature range of $160-180\;^{\circ}C$ under constant and well-defined conditions. The delignification was found to be first order with respect to residual lignin and was chemically controlled. The rate of delignification reaction was increased 1.11-1.23 for $10\;^{\circ}C$ temperature increase in the range of $160-180\;^{\circ}C$ range. A mean value of 93% of lignin was removed at the transition between bulk and residual delignification. The influence of cooking temperature on the rate constant was expressed by an Arrhenius-type equation. The obtained activation energy of the delignification reaction was 6,164 cal/mol. The transition point between bulk and residual phase was shifted to lower lignin and carbohydrate yield with the increase of temperature.

• 펄프종이기술
• /
• 제34권2호
• /
• pp.67-72
• /
• 2002

The two stage laccase-assisted delignification process led to significant lignin removal in the non-pressurized treatments. It is clearly shown that an alkaline extraction prior to the second laccase treatment significantly increased the overall delignification by ∼15%. This is in line with the contention that the residual lignin has undergone structural changes during the alkaline extraction, and the resulting modified structures are susceptible to the laccase oxidation. In phenolic hydroxyl group, the pre- methylated sample was very responsive to the delignification process. The phenolic hydroxyl groups could be increased during side chain cleavage catalyzed by laccase. This finding demonstrates that the delignification oi etherified structures is an important reaction in the delignificaton by laccase.

• Journal of the Korean Wood Science and Technology
• /
• 제18권4호
• /
• pp.18-25
• /
• 1990

As polysaccharides in lignocellulosic materials are encrusted with aromatic lignin molecules and have high crystallinity, these require pretreatment to improve their digestability by cellulolytic enzymes. Though a number of pretreatment methods have been proposed, the steam explosion process is evaluated as a promising method. This study was performed to investigate the effect of delignification treatment by alkali, methanol and the others on the enzymatic hydrolysis. Delignification treatment resulted in great increase rate in enzymatic hydrolysis. Concerning to the effect of delignication reagents on the enzymatic hydrolysis, methanol treatment was more effective than alkali in the case of oak wood. In pine wood, the delignification did not showed any significant enhancement of hydrolysis rate. Complete delignification by Alkali-Oxygen. Alkali treatment showed high saccharification rate of 99.5%.

• Journal of the Korean Wood Science and Technology
• /
• 제20권3호
• /
• pp.11-20
• /
• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• Journal of the Korean Wood Science and Technology
• /
• 제43권1호
• /
• pp.9-16
• /
• 2015

본 연구에서는 고온증기 및 오존 전처리로 제조된 리그노셀룰로오스 나노섬유의 탈리그닌 처리가 나노섬유 및 나노종이의 특성에 미치는 영향을 평가하였다. 형태학적 특성 관찰 결과, 탈리그닌 처리에 의해 평균 직경 35 nm 이하의 균일한 섬유가 얻어졌다. 또한 탈리그닌 처리는 리그노셀룰로오스 나노섬유의 비표면적을 크게 향상시켰으며, 특히 오존 전처리의 경우는 탈리그닌 처리에 의해 무처리에 비하여 1.5배 증가하였다. 나노종이 제조 과정 중의 여수시간 또한 탈리그닌 처리에 의해 크게 증가하여, 고온증기 전처리의 경우는 탈리그닌 처리에 의해 무처리와 비교하여 5.4배 증가하였다. 탈리그닌 처리는 나노종이의 백색도를 향상시켰으며, 고온증기 전처리의 경우는 탈리그닌 전과 비교하여 색상차가 41.9로 매우 높게 나타났다. 나노종이의 인장강도, 탄성율 및 신장율도 탈리그닌에 의하여 크게 향상되었으며, 고온증기 전처리 후의 탈리그닌에 의한 나노종이의 인장강도가 142 MPa로 가장 높게 나타났다.

• 펄프종이기술
• /
• 제33권5호
• /
• pp.25-29
• /
• 2001

Dimethyldioxirane (DMD), which is a source of active oxygen, is effective agent that can be used in chemical pulp bleaching. In this study, delignification of kraft bagasse pulp has been carried out by using DMD. The effect of the applied charge of DMD (as active oxygen) and pH of the delignification medium were studied. The optimum conditions of the applied DMD charge and pH of the delignification reaction were achieved at pH range from 8~9, 2% of DMD (as active oxygen) and the rest of delignification reaction conditions were $25^{\circ}C$, 60 min, and 12% pulp consistency. The development of brightness per unit kappa number removal (ΔBrightness/ Δ Kappa number) has highest value at the optimum condition. The study showed that the reactivity of kraft bagasse pulp be enhanced to wards alkaline hydrogen peroxide bleaching by pulp treatment with DMD.

• Journal of the Korean Wood Science and Technology
• /
• 제20권1호
• /
• pp.60-71
• /
• 1992

To investigate the delignification behaviour in solvolysis pulping process, Populus alba ${\times}$ glandulosa H. and Pinus Kuraiensis S. et Z. were cooked with p-cresol and vater solvent(2:8, 5:5, 8:2 v/v) at $175^{\circ}C$ for 9 cooking time levels(20, 40, 60, 80, 100, 120, 140, 160, 180, min). Pulp yield, residual lignin content, de lignification rate, decarborhydration rate were determined. Delignification behaviours were analyzed by TEM. 1. The p-cresol-water solvent cooking of P. alba ${\times}$ glandulosa showed good delignification at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v), while the cooking of P. koraiensis with the p-cresol and water mixture ratio of 5:5 was no good. 2. P. alba ${\times}$ glandulosa showed three step-delignification phenomena at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v) anti 5:5(v/v). But P. koraiensis showed a first order delignification reaction at the same mixture ratio of p-cresol and water solvent system. 3. In TEM micrograph obtained for the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), the partial delignification of the cell corner of P. alba ${\times}$ glandulosa and P. koraiensis were observed at 60min. of cooking time. Complete delignification at the cell corner of P. alba ${\times}$ glandulosa was observed at 160min. and that of P. koraiensis was observed of 180min. of cooking time. 4. In optical microscopic observation, fiber separation of P. alba ${\times}$ glandulosa occured at 120min. and that of P. koraiensis began at 140min. of cooking time. 5. At the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), middle layer on secondary wall($S_2$) and cell corner of P. alba ${\times}$ glandulosa were more selectively delignified than primary wall(P) and outer layer on secondary wall($S_1$). However P. koraiensis did not showed any difference in delignification between cell wall layers and cell corner.

• 펄프종이기술
• /
• 제37권5호통권113호
• /
• pp.50-55
• /
• 2005

In previous report, we investigated the impact of hexeneuronic acid and some residual extractiveson lignin determination. These non-lignin components severely interfered lignin content determination which also affect on the oxygen delignification comparison between aspen and pine unbleached kraft pulps. Very different pattern was observed whether based on uncorrected conventional kappa number or based on corrected kappa number in oxygen delignification comparison. Lower kappa number aspen pulps showed poor response to oxygen delignification when kappa number was used as lignin determination method but better response with using the acid lignin method. Phenolic hydroxyl group in kraft pulps were also compared based on uncorrected or corrected kappa numberfor lignin content. Based on uncorrected kappa number, lower kappa number oxygen-delignified pulps had lower phenolic hydroxyl group. However, lower kappa number oxygen-delignified pulps showed much higher phenolic hydroxyl group based on the corrected lignin content. For accurate comparison for residual lignin properties from different pulps, lignin determination should be corrected from non-lignin components contribution to lignin.