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1.
Our previous paper showed tobacco stalks to posses the characteristics of a raw material for pulp and paper application. It contains the major biomass constituents and cell components common to wood species. In this study, preparation and characterization of tobacco stalk pulp by steam explosion (SE) pulping at two chemical pretreatments were attempted. Chemical pretreatment prior to SE pulping improved the brightness, yield, and strength properties of the resulting tobacco SE pulps in the order: 6% Na2SO3 + 1% NaOH > 6% Na2SO3 > control (untreated). The 6% Na2SO3 + 1% NaOH-impregnated tobacco stalks produced SE pulps of good fiber length distribution and considerable properties that compare well with pulps from other raw materials obtained from previous studies, and the nonimpregnated ones showed strength properties superior to those of their poplar counterpart. Prior to bleaching, pretreating the tobacco stalk SE pulps with two stages, 2% NaOH at 90°C, improved the initial pulp brightness by about 5 points. Two-stage 6% H2O2 bleaching gave a comparable effect with hypochlorite bleaching for both tobacco and poplar, giving a 29–34 brightness point increase for tobacco SE pulp and 61 for the poplar samples. The differences in the bleaching responses for untreated tobacco and poplar SE pulps were attributed to the differences in their lignin structure, as shown in the total yield of their respective nitrobenzene oxidation products and FT-IR spectra. Tobacco SE pulps contain more of the guaiacyl-type lignin and poplar the syringyl-type lignin.This paper was presented in part during the 1998 CORESTA (Cooperation Centre for Scientific Research Relative to Tobacco) Congress, Brighton, UK, October 1998 相似文献
2.
In this study, the response of Eucalyptus camaldulensis and Acacia mangium kraft pulp to different options of ECF bleaching was investigated. Oxygen-delignified pulps of both species having similar
kappa number (c.a. 12) were used. Both the pulps were prebleached using conventional ClO2 stage (D0), combined use of ClO2 and O3 (DZ), hot acid treatment before D0 (AhotD0) and hot acid treatment before (DZ) i.e., Ahot(DZ), hot ClO2 treatment (DHT) and Ahot followed by DHT (AhotDHT). All prebleached pulps were finally bleached to 90%+ ISO brightness using D1 option. The overall benefits of other options were not considerable compared to D0 and (DZ). From the ClO2 consumption point of view, for a certain species, the option Ahot(DZ) was the best. Instead of D1 in final bleaching, pressurized hydrogen peroxide (PO) was also investigated in the case of D0 and (DZ) prebleached pulps. (PO)-bleached pulp produced higher brightness stability but lower viscosity compared to D1. 相似文献
3.
The purpose of this study was to investigate the behavior of lignin and carbohydrates in kraft pulps during sulfuric acid bleaching. Beech kraft pulp and red pine kraft pulp were bleached with dilute sulfuric acid at pH 1.3 with addition of sodium nitrate and sodium nitrite at 100°C for 1 h. The pulps were then extracted with aqueous sodium hydroxide solution at 70°C for 1 h. Lignin and carbohydrates in the acid effluents and the alkali effluents were analyzed. The carbohydrate compositions of unbleached and bleached kraft pulps were also determined. The residual lignin in kraft pulp was degraded to a molecular size similar to that of milled wood lignin during sulfuric acid bleaching without additives, and it was further degraded to a much smaller molecular size during sulfuric acid bleaching with additives. It was found that the amount of carbohydrate dissolved in the bleach effluents were only about 1 of the dry weight of the kraft pulp under these bleaching conditions. The carbohydrates dissolved during bleaching were mostly of hemicellulose origin.Part of this report was presented at the 8th International Symposium on Wood and Pulping Chemistry, Helsinki, July 1995 相似文献
4.
M. Sarwar Jahan 《Wood Science and Technology》2009,43(3-4):213-224
Dissolving pulps are the raw materials for the production of many different end-products. Jute is a very good source of cellulose. In this investigation, jute fiber was subjected to pulping in soda process in order to produce dissolving pulp under different prehydrolysis conditions and compared with prehydrolysed kraft pulp from jute. An increase of the prehydrolysis temperature or H2SO4 in prehydrolysis liquor increased the α-cellulose content and decreased the viscosity of pulp. The effect of ethylenediamine in soda liquor was also investigated when producing dissolving pulp. Jute fiber produced pulp having 90–97% α-cellulose. Ethylenediamine in soda liquor produced pulp of higher yield, viscosity and higher α-cellulose content than that of prehydrolysis soda or kraft pulp. The α-cellulose content and viscosity were increased with the increase of amine in soda liquor. The kappa number of dissolving pulp from jute was very low (9–5), which indicated that less bleaching chemicals are required for bleaching. The bleachability of soda-ethylenediamine pulp was lower than prehydrolysed soda and kraft pulp in ECF bleaching sequences. The bleachability of soda-ethylenediamine pulp was improved at the sacrifice of pulp yield when prehydrolysis was done prior to pulping. The alkali solubility S 10 and S 18 were 4–9 and 2–4%, respectively. 相似文献
5.
生物技术在制浆造纸工业中的应用前景 总被引：4，自引：0，他引：4
在制浆造纸工业中应用生物技术，在提高纸浆得率、降低纤维原料消耗量、消除污染、节约能源等方面具有较大潜力。作者从几个方面论述了生物技术的应用前景：生物改良树种、原木肃皮和木片贮存、生物制浆和漂白、高质量溶解浆的生产、废纸脱墨、利用造纸废液和废料制取副产品、废水处理。 相似文献
6.
Acetic acid pulping of wheat straw under atmospheric pressure 总被引：4，自引：0，他引：4
Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw was made of the chemical composition, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and fractionated into pulp (cellulose), acetic acid lignin, and sugars (monosaccharides from hemicellulose), making it easy to utilize them. It was found that among the pulping conditions the dosage of H2SO4 as catalyst was the most notable, and the extent and rate of delignification could be controlled by varying the amount of the catalyst. The results also showed that acetic acid pulp was quite different from soda-AQ pulp. About 70% of the ash or 90% of the silica in wheat straw were kept in AcOH pulp. The ash might function as filler and be beneficial to the printability of paper. It was known that many epidermal cells existed in AcOH pulp in bundles or in single cells. These ash-rich nonfiber cells seemed to hinder the bonding between fibers. AcOH pulp had lower strength than soda-AQ pulp, which might result mainly from the chemical damage of fibers caused by acid, not from the depolymerization of cellulose.Part of this paper was presented at the 65th Pulp and Paper Research Conference of Japan TAPPI, Tokyo, June 1998 相似文献
7.
Summary The oxygen (1s) ESCA peak for aspen explosion pulp consists of two components, O1 and O2. A tentative assignment was made for them. O1 with lower binding energy is assigned to oxygen in lignin; while O2 comes mainly from the oxygen elements in carbohydrates. Thus, an O1 area percentage might be viewed as a measure of lignin exposed on the fiber surface. Sulfur (2p) spectra show that the sulfur on the fiber surface of the pulps studied here is in the form of sulfonate groups. Compared to conventional pulps, the lower percentage of O1 and higher sulfur-to-carbon ratio for explosion pulps imply higher number of hydrophilic groups exposed on their fiber surface. 相似文献
8.
Summary Explosion pulping results in strong pulp with breaking length at 100 ml CSF (Canadian standard freeness) higher than 6.5 kg and burst index approaching 4 KPa m2/g. The real advantage of eucalyptus explosion pulp over conventional CMP (chemical-mechanical pulp) and CTMP (chemical-thermo-mechanical pulp) is observed when the impregnation solution contains less than 2% NaOH along with 8% Na2SO3, and when the liquor/chips ratio equals 3. The strength of eucalyptus explosion pulp obtained by using a pretreatment solution consisting of 8% Na2SO3 and 1% NaOH is comparable with that of eucalyptus kraft pulp. The concentration of NaOH present in the pretreatment solution has a very important effect on the specific refining energy of eucalyptus explosion pulp as well as of CMP and CTMP. The explosion pulp obtained from eucalyptus pretreated with a solution containing an appropriate quantity of caustic along with Na2SO3 not only requires a minimum specific refining energy but also provides the highest strength values in comparison to that of CMP and CTMP. 相似文献
9.
Chemical changes in cell wall components of bamboo internode during steam explosion process were analyzed to investigate self-binding
mechanism of binderless board from steam-exploded pulp. More than 30% of xylose on initial mass, which is a major hydrolyzate
of bamboo hemicelluloses, was lost after steam explosion treatment. Bamboo lignin is characterized by the presence of ester-
and/or ether-linked p-coumaric acid to lignin. The content of phenolic hydroxyl groups of lignin isolated from steam-exploded pulp was characterized
2.3 times higher than those of the extract-free bamboo internode due to the cleavage of β-O-4 linkages. Alkaline nitrobenzene
oxidation of the bamboo lignin gave vanillin, syringaldehyde and p-hydroxybenzaldehyde as major products. The content of p-hydroxybenzaldehyde decreased after steam explosion treatment, indicating the cleavage of ester- and/or ether-linked p-coumaric acid. The total yield of erythronic and threonic acids in ozonation products of the extract-free bamboo internode
lignin was 268 mmol (200 g lignin)−1, while those of lignins in the steam-exploded pulp and powdery fraction were 96 and 129 mmol (200 g lignin)−1, respectively, suggesting the significant cleavage of β-O-4 linkages during steam explosion treatment. The cleavage of β-O-4
linkages was also confirmed by 1H- and 13C-NMR spectroscopic observations. 相似文献
10.
Bamboo (Phyllostachys pubescens) internode was subjected to steam explosion treatment to produce an excellent fiber for binderless boards. Lignin was isolated from extract-free bamboo meal with Björkman’s procedure and steam-exploded pulp. The self binding-mechanism was discussed by scanning electron microscopy (SEM), thermo-gravimetry (TG), differential scanning calorimetry (DSC) and analytical ozonation. It is well-known that steam explosion treatment liberates lignin from the cell wall to the fiber surface, which is the most important component relevant to binderless board production. Results of TG and DSC analyses showed that steam-exploded bamboo pulp started mass loss at lower temperature compared to bamboo internode meal. The thermal softening temperature of lignin prepared from steam-exploded pulp was much lower than that of lignin prepared from extract-free bamboo meal. This suggests that intermonomer linkages of lignin, especially β-aryl-ether linkage which is the major intermonomer linkage of lignin, were cleaved during steam explosion treatment resulting in low molecular weight phenolic compounds. The cleavage of β-aryl-ether intermonomer linkage of lignin was also confirmed by ozonation analysis. 相似文献
11.
12.
Summary Four species of fast growing annual plant viz.Hibiscus sabdariffa, Crotalaria juncea, Tephrosia candida andHibiscus cannabinus and a variety of reed, Neyraudia reynaudiana were evaluated in the laboratory for their pulp and paper making properties. Data on proximate chemical analysis of raw materials, unbleached and bleached pulp properties, morphological properties of fibres and physical strength properties of paper sheets were evaluated. The unbleached pulp yields were 44.90–53.20% with all the five plant materials, while bleached pulp yields varied from 39.80–50.60%. The average fibre lengths and diameters of the unbleached pulp obtained from the five plant species were within the range of 0.75 mm–2.15 mm and 20–22 pun respectively. Paper hand sheets, made with bleached pulps (45° SR) obtained from the five plant species, gave burst indices 2.75–3.92 kPa m2/g, tear indices 3.73–9.61 m N m2/g and tensile indices 37.27–47.81 N mg–1, indicating adequate strength properties for writing and printing type of paper.The authors thank Director, Regional Research Laboratory (CSIR), Jorhat, India, for his kind permission to publish this paper. The authors also wish to thank B. N. Tosh, JPF for his assistance. 相似文献
13.
We investigated the impact of residual extractives on lignin determination by lignin content difference between unextracted
and extracted pulps, residual extractives analysis, and lignin content contribution from model extractive compounds. There
were two different kinds of extractives in aspen kraft pulp. The extractives impacting on kappa number determination were
well removed in oxygen delignification; these were mainly unsaturated fatty acids. However, the extractives impacting on Klason
lignin determination were largely resistant to oxygen delignification; these were mainly saturated fatty acids, sterols, and
hydrocarbons. Oxidation of unsaturated fatty acids was the main reaction in oxygen delignification. These trends were confirmed
by simulation of lignin content determination with three model extractive compounds (β-sitosterol, linoleic acid, and palmitic acid).
The publication of this article was made possible by an Emachu Research Fund. The authors are grateful for the fund. 相似文献
14.
Assist. Prof. Dr. H. Kirçi Prof. Dr. S. Bostançi Assist. Prof. Dr. M. K. Yalinkiliç 《Wood Science and Technology》1994,28(2):89-99
Summary In this study, ASAM method was modified by the use of ethanol instead of methanol. This new organosolv pulping method is referred to as ASAE. Brutia pine (Pinus brutia Ten.) was chosen as raw material in cooking because of its wide-spread usage in Turkish sulphate mills. 28 cooks were made by changing the cooking conditions systematically to achieve the most effective cooking parameters for yield and physical properties of ASAE pulps. Also, a control sulphate cook was made. After statistical evaluations of the data optimum pulping conditions were determined to be 20% Na2SO3 with 50% ethanol ratios and 150 min cooking time at maximal temperature. It was found that ASAE pulps had higher yield, viscosity, brigthness and strength properties than sulphate control pulps with the exception of breaking length. Furthermore bad-odour problems were absent during the blowing and washing process in the laboratory trials. 相似文献
15.
bamboo(Phyllostachys edulis) residue was subjected to steam explosion treatment to produce superior fibers for binderless boards.Then,lignin was isolated from extract-free bamboo meal,steam exploded pulp,and binderless boards with characteristics being determined by thermo-gravimetry (TG),differential scanning calorimetry (DSC),and fourier transform infrared spectroscopy (FTIR).Results showed that:1) the yield of lignin directly extracted with dioxane-water from steam exploded bamboo pulp(SEBPL) and binderless board (SEBBL) was higher than that of milled bamboo lignin (MBL).Also,the yield of SEBBL was lower than that of SEBPL.2) FTIR results showed cleavage of ester and ether bonds between lignin and p-coumaric acid during steam explosion treatment.3) SEBBL showed two glass transitions at 115℃and 200℃, while MBL gave one glass transitions at 155℃.And 4) the modulus of rupture(MOR) and modulus of elasticity(MOE) decreased with an increase in steaming time;whereas internal bonding(IB) increased.In all cases the dimensional stability of boards did not exceed the maximum requirements for type GB/T 11718- 1999. 相似文献
16.
Summary The surface composition of explosion pulp and conventional CMP and CTMP underwent ESCA spectroscopy. Explosion pulps exhibited a higher oxygen-to-carbon ratio and less C1 peak areas compared to conventional CMP/CTMP. Based on the theoretical O/C ratios and C1 contents for the main components of wood fibers (i.e., carbohydrates, lignin and extractives), a triangular graph was used to illustrate the relative amounts of the three components on the surface. This analysis indicated that explosion pulps had more carbohydrates exposed on their fiber surface, which may explain their high physical strength. A bulk analysis indicated that these differences could not depend on their bulk compositions, since the latter were similar. 相似文献
17.
Thermoplastic processing of lignin is restricted by its high glass transition temperature (T g). In this study, lignin was modified with polyethylene glycol (PEG) during steam explosion to improve its thermoplastic properties, and the effects of steam explosion and PEG on the chemical structure and thermal properties of lignin were investigated. Structure characterization using Fourier transform infrared spectroscopy showed that hydroxyl and ether functional groups increased and the activity of lignin was improved by steam explosion. In addition, steam explosion treatment was more effective than heat treatment for promoting the reaction of PEG with lignin. Solid-state 13C NMR revealed that PEG was grafted onto lignin. The T g of raw lignin was 164.1 °C; after steam explosion, lignin exhibited more than one T gs. The T g of lignin was reduced when the steam explosion temperature increased and decreased further, to around 60 °C, when PEG was used to modify lignin. Therefore, this work provides an effective approach to reducing the high T g of lignin. 相似文献
18.
Summary The acetyl bromide procedure for spectrophotometrically determining lignin in wood and wood pulp samples has been modified by adding perchloric acid to the digestion medium. This enables faster dissolution of the materials and the use of coarser samples. Subsequent treatment of the digestion mixtures with larger amounts of sodium hydroxide than those used in the conventional procedure has obviated the need for treatment with hydroxylamine. The modified method has been successfully applied to woodmeals and pulps from Pinus radiata and Eucalyptus species. 相似文献
19.
A marine white rot isolate, Phlebia sp. MG-60, secreted lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase under different sea salt incubation conditions.
Its MnP production was strongly enhanced by adding 3% sea salts, and the MnP showed high tolerance to sea salts and NaCl.
The crude enzyme secreted at 3% sea salt concentration by Phlebia sp. MG-60, in which the main component was MnP (cMnP), was then used to bleach unbleached hardwood kraft pulp (UKP) in vitro.
The pulp was brightened 11 points by 4 U of cMnP, and the kappa number was decreased 6 points when only 0.5 mM H2O2 was added continuously. When 0.5 mM H2O2 (1.22 mg H2O2 /g pulp) was added at the initial bleaching, the pulp brightness increased 6 points with a dosage of 4 U of cMnP. When crude
MnPs were employed to bleach UKP with organic-free model white-water instead of the Milli Q water usually used, the pulp was
brightened 10 and 13 points by 4 and 20 U of cMnP, respectively, and 5 and 6 points by 4 and 20 U of MnP, respectively, of
Phanerochaete chrysosporium.
Received: September 28, 2001 / Accepted: March 15, 2002
Correspondence to:R. Kondo 相似文献
20.
Elisabete V. Costa Diana L. D. Lima Dmitry V. Evtyugin Valdemar I. Esteves 《Wood Science and Technology》2014,48(1):99-108
A capillary zone electrophoresis (CZE) method for simple and rapid determination of ellagic acid (EA) in Eucalyptus globulus wood and in the filtrate from unbleached kraft pulp has been developed. This is the first application of CZE for the detection of EA in industrial streams from cellulosic pulp production. The EA determinations in wood extractives and in pulp filtrates were succeeded only after sample acidification. This new CZE analytical procedure allowed reliable determinations of EA in E. globulus wood (1.1 ± 0.6 g kg?1 of dry wood) and in the filtrates from unbleached kraft pulp (98 ± 0.7 mg L?1). Gas chromatography–mass spectrometry was used as a reference method for the quantification of EA in industrial samples. 相似文献