Polyoxometalate Delignification of Birch Kraft Pulp and Effect on Residual Lignin

2011 ◽  
Vol 31 (2) ◽  
pp. 121-141 ◽  
Author(s):  
Biljana Bujanovic ◽  
Richard S. Reiner ◽  
Sally A. Ralph ◽  
Rajai H. Atalla
Keyword(s):  
Kraft Pulp ◽  
Residual Lignin ◽  
Birch Kraft Pulp

scholarly journals Cellulose Nanofibril (CNF) Films and Xylan from Hot Water Extracted Birch Kraft Pulps

2019 ◽  
Vol 9 (16) ◽  
pp. 3436 ◽  
Author(s):  
Marc Borrega ◽  
Hannes Orelma
Keyword(s):  
Food Packaging ◽  
Kraft Pulp ◽  
Barrier Properties ◽  
Hot Water ◽  
Kraft Pulps ◽  
Cellulose Nanofibril ◽  
Vapour Permeability ◽  
Transparent Films ◽  
Cnf Films ◽  
Birch Kraft Pulp

The effects of xylan extraction from birch kraft pulp on the manufacture and properties of cellulose nanofibril (CNF) films were here investigated. Hot water extractions of bleached and unbleached kraft pulps were performed in a flow-through system to remove and recover the xylan. After the extraction, the pulps were oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and fibrillated in a high-pressure microfluidizer. Compared to CNF from bleached kraft pulp, the CNF dispersions obtained from water-extracted pulps were less viscous and generally contained a higher amount of microfiber fragments, although smaller in size. In all cases, however, smooth and highly transparent films were produced from the CNF dispersions after the addition of sorbitol as plasticizer. The CNF films made from water-extracted pulps showed a lower tensile strength and ductility, probably due to their lower xylan content, but the stiffness was only reduced by the presence of lignin. Interestingly, the CNF films from water-extracted bleached pulps were less hydrophilic, and their water vapour permeability was reduced up to 25%. Therefore, hot water extraction of bleached birch kraft pulp could be used to produce CNF films with improved barrier properties for food packaging, while obtaining a high-purity xylan stream for other high-value applications.

Surface selective removal of xylan from refined never-dried birch kraft pulp

Cellulose ◽  
2014 ◽  
Vol 21 (5) ◽  
pp. 3677-3690 ◽  
Author(s):  
Esa Saukkonen ◽  
Katja Lyytikäinen ◽  
Pavel Geydt ◽  
Kaj Backfolk
Keyword(s):  
Kraft Pulp ◽  
Selective Removal ◽  
Birch Kraft Pulp

Isolation of residual lignin from softwood kraft pulp. Advantages of the acetic acid acidolysis method

2004 ◽  
Vol 327 (9-10) ◽  
pp. 911-916 ◽  
Author(s):  
Dominique Lachenal ◽  
Gérard Mortha ◽  
Rose-Marie Sevillano ◽  
Michail Zaroubine
Keyword(s):  
Acetic Acid ◽  
Kraft Pulp ◽  
Residual Lignin ◽  
Softwood Kraft Pulp

Fate of Residual Lignin during Delignification of Kraft Pulp by Trametes versicolor

1998 ◽  
Vol 64 (6) ◽  
pp. 2117-2125 ◽  
Author(s):  
Ian D. Reid
Keyword(s):  
Trametes Versicolor ◽  
Kraft Pulp ◽  
Lignin Degradation ◽  
Water Soluble ◽  
Kraft Pulps ◽  
Residual Lignin ◽  
Spruce Wood ◽  
Single Ring ◽  
Enzyme Bleaching ◽  
By Products

ABSTRACT The fungus Trametes versicolor can delignify and brighten kraft pulps. To better understand the mechanism of this biological bleaching and the by-products formed, I traced the transformation of pulp lignin during treatment with the fungus. Hardwood and softwood kraft pulps containing 14C-labelled residual lignin were prepared by laboratory pulping of lignin-labelled aspen and spruce wood and then incubated with T. versicolor. After initially polymerizing the lignin, the fungus depolymerized it to alkali-extractable forms and then to soluble forms. Most of the labelled carbon accumulated in the water-soluble pool. The extractable and soluble products were oligomeric; single-ring aromatic products were not detected. The mineralization of the lignin carbon to CO2 varied between experiments, up to 22% in the most vigorous cultures. The activities of the known enzymes laccase and manganese peroxidase did not account for all of the lignin degradation that took place in the T. versicolor cultures. This fungus may produce additional enzymes that could be useful in enzyme bleaching systems.

scholarly journals Alkali Extraction of Kraft Pulp Fibers: Influence on Fiber and Fluff Pulp Properties

2012 ◽  
Vol 7 (2) ◽  
pp. 155892501200700 ◽  
Author(s):  
Kristoffer Lund ◽  
Karin Sjöström ◽  
Harald Brelid
Keyword(s):  
Kraft Pulp ◽  
Pulp Fibers ◽  
Fiber Network ◽  
Alkali Extraction ◽  
Flexible Fiber ◽  
Softwood Pulp ◽  
Softwood Kraft Pulp ◽  
Patent Literature ◽  
Network Strength ◽  
Birch Kraft Pulp

The importance of hemicelluloses for the papermaking properties of pulp fibers is well documented. In the patent literature, it can be seen that there is also an interest in this type of modification of pulp fibers for use in absorption products. In this study, a Scandinavian softwood kraft pulp and a birch kraft pulp were alkali extracted at 3 different concentrations of NaOH (2%, 4% and 8% NaOH in the suspension). The alkali extraction removed a large part of the hemicelluloses from the pulp fibers and decreased the content of the charged groups. After extraction, the pulps were dried in the form of sheets (approx. 600 g/m2). The alkali extracted pulp fibers exhibited a greater decrease in swelling when re-wetted than untreated pulp. A significant increase in the curl index after extraction with 4% and 8% NaOH was also noted. The tensile strength index of the formed sheets increased at the lowest concentration of NaOH and, at the higher concentrations, a decrease was observed. The pulp sheets were dry defibrated at different defibration intensities and the performance of the resulting pulps in fluff pulp applications was studied. The air-laid fiber networks of softwood pulp fibers showed higher network strength than the networks of birch pulps. The birch pulp extracted at the highest alkali level tended to give the highest network strength. The results from the network strength tests also indicated that the increased curl of the fibers from the softwood pulp extracted at the highest alkali level rendered a more flexible fiber network. In water absorption tests, the alkali treated softwood fibers tended to give networks with a somewhat enhanced water holding capacity under pressure.

Impact of hemicellulose pre-extraction for bioconversion on birch Kraft pulp properties

2010 ◽  
Vol 101 (15) ◽  
pp. 5996-6005 ◽  
Author(s):  
Jonas Helmerius ◽  
Jonas Vinblad von Walter ◽  
Ulrika Rova ◽  
Kris A. Berglund ◽  
David B. Hodge
Keyword(s):  
Kraft Pulp ◽  
Pulp Properties ◽  
Birch Kraft Pulp

Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 492-498 ◽  
Author(s):  
Biljana Bujanovic ◽  
Sally A. Ralph ◽  
Richard S. Reiner ◽  
Rajai H. Atalla
Keyword(s):  
Kraft Pulp ◽  
Lignin Content ◽  
Kappa Number ◽  
Ring Cleavage ◽  
Residual Lignin ◽  
Glucose Content ◽  
Lower Glucose ◽  
Softwood Kraft Pulp ◽  
Alkaline Conditions ◽  
Extraneous Material

Abstract Commercial softwood kraft pulp with kappa number 30.5 (KP30.5) was delignified with polyoxometalates (POM, Na5(+2)[SiV1(-0.1)MoW10(+0.1)O40]), and POM-treated kraft pulp of kappa number 23.6 was obtained (KPPOM,23.6). Residual lignin from pulps was isolated by mild acid hydrolysis and characterized by analytical and spectral methods to gain insight into lignin reactions taking place during the initial delignification phase. Lignin from POM-delignified pulp was isolated in lower yield. Comparative analysis of residual lignins (RL-KP30.5, RL-KPPOM,23.6) showed that POM leads to products enriched in carbonyl/carboxyl groups and carbohydrates. POM lignins have a lower molecular mass and a lower content of phenolic hydroxyl and methoxyl groups. Based on these results and FTIR spectra, we suggest that aromatic ring cleavage and quinone formation occur during POM delignification. The degree of lignin-cellulose association increases after POM delignification. Lignin-cellulose association was found to be partially unstable under mild alkaline conditions, as residual lignin isolated after alkaline extraction of KPPOM,23.6 pulp (RL-KPPOM/NaOH) exhibited lower glucose content, higher Klason lignin content, and less extraneous material.

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