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  • 101.
    Mikael, Lindström
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Continuous digester for cellulose pulp including method and recirculation system for such digester: Kontinuerlig kokare förfarande för drift av kontinuerlig kokare och återföringssystem för kokvätska i en kontinuerlig kokare2001Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention relates to a continuous digester for producing chemical pulp, to a process for operating this digester and to a feedback system for the cooking liquid. By means of implementing cooking zones 1st, 2nd, 3rd, 4th and 5th down through the digester, having a successively decreasing liquid-to-wood ratio, it is possible to obtain a more uniform alkali profile during the cooking. The alkali which is totally available is kept high at the beginning by means of a high liquid-to-wood ratio, typically well over 6:1, which well exceeds conventional liquid-to-wood ratios, which are normally around 3.5-5.0:1. In combination with digester liquid from subsequent cooking zones being fed back to the top of the digester, the alkali concentration can be kept low at the beginning of the cooking, typically within 20-35 g/l when cooking softwood. This is achieved with essentially all the alkali, i.e. more than 80 %, being added at the beginning of the cooking. A more uniform alkali profile is favourable for the cooking process and gives an improved pulp quality.

  • 102.
    Morais de Carvalho, Danila
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Abad, Antonio Martinez
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Evtuguin, D. V.
    Colodette, J. L.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Vilaplana, Francisco
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Isolation and characterization of acetylated glucuronoarabinoxylan from sugarcane bagasse and straw2017Inngår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 156, s. 223-234Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sugarcane bagasse and straw are generated in large volumes as by-products of agro-industrial production. They are an emerging valuable resource for the generation of hemicellulose-based materials and products, since they contain significant quantities of xylans (often twice as much as in hardwoods). Heteroxylans (yields of ca 20% based on xylose content in sugarcane bagasse and straw) were successfully isolated and purified using mild delignification followed by dimethyl sulfoxide (DMSO) extraction. Delignification with peracetic acid (PAA) was more efficient than traditional sodium chlorite (NaClO2) delignification for xylan extraction from both biomasses, resulting in higher extraction yields and purity. We have shown that the heteroxylans isolated from sugarcane bagasse and straw are acetylated glucuronoarabinoxylans (GAX), with distinct molecular structures. Bagasse GAX had a slightly lower glycosyl substitution molar ratio of Araf to Xylp to (0.5:10) and (4-O-Me)GlpA to Xylp (0.1:10) than GAX from straw (0.8:10 and 0.1:10 respectively), but a higher degree of acetylation (0.33 and 0.10, respectively). A higher frequency of acetyl groups substitution at position α-(1 → 3) (Xyl-3Ac) than at position α-(1 → 2) (Xyl-2Ac) was confirmed for both bagasse and straw GAX, with a minor ratio of diacetylation (Xyl-2,3Ac). The size and molecular weight distributions for the acetylated GAX extracted from the sugarcane bagasse and straw were analyzed using multiple-detection size-exclusion chromatography (SEC-DRI-MALLS). Light scattering data provided absolute molar mass values for acetylated GAX with higher average values than did standard calibration. Moreover, the data highlighted differences in the molar mass distributions between the two isolation methods for both types of sugarcane GAX, which can be correlated with the different Araf and acetyl substitution patterns. We have developed an empirical model for the molecular structure of acetylated GAX extracted from sugarcane bagasse and straw with PAA/DMSO through the integration of results obtained from glycosidic linkage analysis, 1H NMR spectroscopy and acetyl quantification. This knowledge of the structure of xylans in sugarcane bagasse and straw will provide a better understanding of the isolation-structure-properties relationship of these biopolymers and, ultimately, create new possibilities for the use of sugarcane xylan in high-value applications, such as biochemicals and bio-based materials. © 2016 Elsevier Ltd

  • 103.
    Moraisde Carvalho, Danila
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. Univ Fed Vicosa, Dept Forestry Engn, Pulp & Paper Lab, BR-36570900 Vicosa, MG, Brazil.
    Martinez Abad, Antonio
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Colodette, Jorge Luiz
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Vilaplana, Fransisco
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Comparative characterization of acetylated heteroxylan from eucalyptus, sugarcane bagasse and sugarcane strawManuskript (preprint) (Annet vitenskapelig)
  • 104.
    Moraisde Carvalho, Danila
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. Univ Fed Vicosa, Dept Forestry Engn, Pulp & Paper Lab, BR-36570900 Vicosa, MG, Brazil.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Penna, Lais Souza
    da Silva, Brunela Pereira
    Lindstrom, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Colodette, Jorge Luiz
    Assessment of chemical transformations in eucalyptus, sugarcane bagasse and straw during hydrothermal, dilute acid, and alkaline pretreatments2015Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 73, s. 118-126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impact of hydrothermal, dilute acid, and alkaline pretreatments on the chemical structure of eucalyptus, sugarcane bagasse, and straw were compared with a view to their subsequent bioconversion into ethanol. Sugarcane bagasse and straw contain high amounts of extractives (15.0% and 12.2%, respectively), ash (2.3% and 7.9%, respectively), and silica (1.4% and 5.8%, respectively). If not properly corrected, the presence of silica would lead to the overestimation of the lignin, while high amounts of extractives would cause the overestimation of the content of sugars in biomass. Applying a novel approach through the use of complete mass balance, bagasse and straw were proven to contain lower amounts of lignin (18.0% and 13.9%, respectively) than previously reported for these raw materials, and certainly a much lower amount of lignin than eucalyptus (27.4%). The syringyl to guaiacyl units ratio (SIG) for lignin in bagasse and straw (1.1 and 0.5, respectively) was lower than that for eucalyptus (2.7), indicating a different reactivity during chemical pretreatments. The xylan content in sugarcane bagasse and straw was much higher than that in eucalyptus, with a significantly lower degree of substitution for uronic acids and acetyl groups. The sugarcane straw showed the highest mass loss during the investigated pretreatments, especially under alkaline conditions, with a total biomass yield of only 37.3%. During the hydrothermal and dilute acid treatments, mostly hemicelluloses were removed, followed by the formation a significant amount of pseudo-lignin structures, while the alkaline pretreatment affected the lignin content. With eucalyptus, the formation of structures similar in their behavior to extractives (i.e., soluble in toluene and ethanol, subsequently referred to as "pseudo-extractives") was observed during all three pretreatments, with 12.4% for hydrothermal, 18.9% for dilute acid, and 8.7% for alkaline pretreatment. This information, combined with actual yields, should be taken into account when assessing the impact of pretreatments on the chemical composition and structure of biomass.

  • 105.
    Moser, Carl
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Backlund, Hanéle
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Drenth, Louise
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Xyloglucan adsorption for measuring the specific surface area on various never-dried cellulose nanofibers2018Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, nr 2, s. 186-193Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we explore xyloglucan adsorption to cellulose nanofibers as a method for the evaluation of their quality (i. e., the degree of disintegration) and the accessible surface area in the wet state and at low ionic strength. This method was shown to be capable of estimating the surface areas of 14 different cellulose nanofiber qualities from both hardwood and softwood with different pretreatments, including enzymatic hydrolysis using a monocomponent endoglucanase, TEMPO-mediated oxidation, and carboxymethylation. The cellulose surface measured using this method showed a correlation with the degree of disintegration expressed as transmittance for different concentrations of xyloglucan.

  • 106.
    Moser, Carl
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Backlund, Hanéle
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Xyloglucan for estimating the surface area of cellulose fibers2018Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, nr 2, s. 194-199Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hemicellulose xyloglucan can be utilized to measure exposed cellulose surfaces for pulp fibers. This was shown by correlating a refining series with the adsorbed amount of xyloglucan, and by swelling cellulose fibers to various degrees by increasing the charge density. The method is specific to cellulose and could be used to quantify refining or to determine hornification.

  • 107.
    Moser, Carl
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Improved dispersibility of once-dried cellulose nanofibers in the presence of glycerol2018Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To investigate the dispersibility of dried cellulose nanofibers (CNFs), various additions (glycerol, octanol, glycol, and sodium perchlorate) were added to CNFs prior to drying. Glycerol was the only species to show any significant effect on re-dispersibility. The sedimentation was slower, and the transmittance of the solution was comparable to that of its undried counterpart. Increasing the amount of glycerol showed a clear trend with regard to dispersibility. The mechanical properties of films were maintained for samples that were dried and redispersed in the presence of glycerol.

  • 108.
    Moser, Carl
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Structural aspects on the manufacturing of cellulose nanofibers from wood pulp fibers2019Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, nr 1, s. 2269-2276Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The exact mechanism behind the disintegration of chemical pulp fiber into cellulose nanofibers is poorly understood. In this study, samples were subjected to various homogenization cycles, indicating that the mechanism is a stepwise process. In the earlier stages of the mechanical process, a large amount of macrofibrils were created as the larger structures disappeared. Upon mechanical treatment these macrofibrils disappeared despite the increasing yield of cellulose nanofibers. The proposed model expands the understanding of the disintegration pathway and may provide additional insight as to how wood cells are converted into microfibrils.

  • 109.
    Moser, Carl
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. Valmet AB, Sweden.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Specific surface area increase during cellulose nanofiber manufacturing related to energy input2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 3, s. 7124-7132Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Softwood fibers pretreated with a monocomponent endoglucanase were used to prepare a series of cellulose nanofiber qualities using a microfluidizer and 2 to 34 MWh ton-1 of energy input. The specific surface area was determined for the series using critical point drying and gas adsorption. Although the specific surface area reached a maximum of 430 m2 g-1 at 11 MWh ton-1, the nanofiber yield and transmittance continued to increase beyond this point, indicating that more energy is required to overcome possible friction caused by an interwoven nanofiber network unrelated to the specific surface area. A new method for estimating the surface area was investigated using xyloglucan adsorption in pure water. With this method it was possible to follow the disintegration past the point of maximum specific surface area. The technical significance of these findings is discussed.

  • 110.
    Moser, Carl
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Toward Industrially Feasible Methods for Following the Process of Manufacturing Cellulose Nanofibers2015Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, nr 2, s. 2360-2375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocellulose is a recently developed form of cellulose that has the potential to be used in many different industries, ranging from food to high-performance applications. This material is commercially manufactured through the homogenization of chemical pulps, but the process is energy-consuming and is still an important subject for development. Simple, robust methods are required for the quality control and optimization of industrial nanocellulose production. In this study, a number of different methods, based on different principles of monitoring the manufacture of cellulose nanofibers were evaluated and compared for five different nanocellulose qualities, both for their resolution and robustness/ease. Methods based on microscopy, light scattering, centrifugation, and viscosity were examined and all appeared useful for observing the manufacturing process during its initial stage. However, only methods based on centrifugation, turbidity, and transmittance yielded reliable data for the entire manufacturing process. Of these methods, transmittance measurement may be the best candidate for routine use because the method is simple, rapid, and only requires spectrophotometer equipment.

  • 111. Myglovets, M.
    et al.
    Poddubnaya, O. I.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Gawdzik, B.
    Sobiesiak, M.
    Tsyba, M. M.
    Sapsay, V. I.
    Klymchuk, D. O.
    Puziy, A. M.
    Preparation of carbon adsorbents from lignosulfonate by phosphoric acid activation for the adsorption of metal ions2014Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 80, s. 771-783Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Activated carbons were prepared from sodium lignosulfonate by phosphoric acid activation at carbonization temperatures of 400-1000 degrees C. The resulting materials were characterized with regard to their surface area, pore volume, pore size distribution, distribution of surface groups and ability to adsorb copper ions. Activated carbons were characterized by nitrogen adsorption, scanning electron microscopy, Fourier transform infrared spectroscopy and thermal gravimetric analyses. The results indicate that with increasing carbonization temperature, the surface area decreased from 770 m(2)/g at 400 degrees C to 180 m(2)/g at 700 degrees C and increased at higher temperatures to 1370 m(2)/g at 1000 degrees C. The phosphorus content peaked at 11% for carbon obtained by carbonization at 800 degrees C. Potentiometric titration revealed the acidic character of all the phosphoric acid-activated carbons, which were found to have total concentrations of surface groups of up to 3.3 mmol/g. The carbons showed a high adsorption capacity for copper ions even at pH values as low as 2.

  • 112. Nilsson, Helena
    et al.
    Olsson, Ann
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lindström, Mikael
    Iversen, Tommy
    Bark Suberin as a Renewable Source of Long-Chain omega-Hydroxyalkanoic Acids2008Inngår i: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 272, nr 1, s. 104-106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polycondensations of cis-9,10-epoxy-18-hydroxyoctadecanoic acid, isolated from birch outer bark, were performed at 75 degrees C in toluene as solvent and at 85 degrees C in bulk using immobilized Candida antarctica lipase B as catalyst. The polycondensation performed in toluene in presence of molecular sieves gave a polyester with DP 50 after 24 h. The same DP was obtained at much shorter reaction time (3 h) by bulk polymerization in an open vial without any drying agent present.

  • 113.
    Olsson, Ann
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael
    Iversen, Tommy
    Lipase-catalyzed synthesis of an epoxy-functionalized polyester from the suberin monomer cis-9,10-epoxy-18-hydroxyoctadecanoic acid2007Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 8, nr 2, s. 757-760Artikkel i tidsskrift (Fagfellevurdert)
  • 114. Olsson, Krister
    et al.
    Lindström, Mikael
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Snekkenes, Vidar
    Process for the manufacturing of cellulose pulp: Förfarande och kokerisystem för framställning av cellulosamassa2002Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention concerns a method for the production of cellulose pulp, in which wood raw material that principally comprises softwood, preferably in the form of cut wood chips, is treated in several stages in various treatment steps, whereby one of the stages comprises cooking the material in an alkali cooking fluid, with the aim of obtaining improved quality with respect to tensile strength, and of obtaining higher yield, whereby a controlled addition of wood raw material in the form of hardwood at an amount corresponding to 1-20% of the amount of softwood, preferably 3-15%, and more preferably at least 5%, takes place.

  • 115. Pettersson, E. A. K.
    et al.
    Ragnar, M.
    Lindström, Mikael
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Kraft cooking characteristics and hexenuronic acid concentration of pulps from Eucalypt and other hardwood species2002Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 17, nr 3, s. 222-227Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fifteen different hardwood species have been investigated with regard to their kraft cooking characteristics. Firstly, all the species were cooked to a reference kappa number of 16.4+/-1.0. The evaluation of the results includes cooking yield, viscosity, xylan content and hexenuronic acid concentration. The difference between the different species is very large in many respects. In a second part of the study, ten Eucalypt species were cooked under identical conditions. Interestingly, the species yielding pulps with the highest kappa numbers also showed the lowest cooking yield, which emphasizes the importance of the choice of Eucalypt species when a forest is planted for pulping purposes. In a third part of the investigation, the mechanisms determining the concentration of hexenuronic acid in a pulp are discussed and exemplified with trials on Oak and Birch.

  • 116. Podkościelna, B.
    et al.
    Gordobil, O.
    Riazanova, Anastasiia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Dobele, G.
    Labidi, J.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gun'ko, V. M.
    Sevastyanova, Olena
    Novel Porous Materials Obtained from Technical Lignins and Their Methacrylate Derivatives Copolymerized with Styrene and Divinylbenzene2017Inngår i: ChemistrySelect, ISSN 2365-6549, Vol. 2, nr 7, s. 2257-2264Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing availability of various types of technical lignins as result of the emergence of new biorefinery technologies has boosted the interest in the commercialization of lignin-based materials. Here we suggest a novel method for the preparation of uniform porous microspheres through emulsion-suspension polymerization of various technical lignins and related methacrylates with styrene (St) and divinylbenzene (DVB). Obtained microspheres have diameters in the range of 5–50 μm, with a more uniform shape for copolymers that contains lignin derivatives. Nitrogen sorption with DFT theory indicates that the microspheres are mesoporous materials with specific surface areas in the range of 230–270 m2g−1 but with significant differences in pore volume, especially in the mesopores size range (0–0.65 cm3g−1). Theoretical modeling of lignin alone and in St-DVB composites shows changes in polarity of the structures, which have become mosaics with hydrophilic and hydrophobic functionalities. This structure affects the properties of the interfacial water and, therefore, can affect the adsorption of both polar and nonpolar adsorbates in solid-phase extraction.

  • 117. Rabinovich, Mikhail L.
    et al.
    Fedoryak, Olesya
    Dobele, Galina
    Andersone, Anna
    Gawdzik, Barbara
    Lindstrom, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Carbon adsorbents from industrial hydrolysis lignin: The USSR/Eastern European experience and its importance for modern biorefineries2016Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 57, s. 1008-1024Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    This paper reviews the origin, distribution and composition of hydrolysis lignin, a large-scale by-product of the hydrolysis industry that operated in the Soviet Union and several eastern European countries from 1930s to the end of 1990s. The fundamental and industrial aspects of the production of various types of powdered and granular carbon adsorbents from hydrolysis lignin are considered through the prism of future large-scale production of biofuels and platform chemicals from renewable lignocellulosic resources. The advantages and drawbacks of hydrolysis lignin as a feedstock for the production of carbon adsorbents are compared with other types of feedstock, and the application of lignin-based carbons is discussed. 

  • 118. Ragnar, M.
    et al.
    Lindström, Mikael
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    A comparison of emerging technologies: hot chlorine dioxide bleaching versus hot acid treatment2004Inngår i: Paperi ja puu, ISSN 0031-1243, Vol. 86, nr 1, s. 39-44Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hot acid treatment and hot chlorine dioxide bleaching are two emerging technologies within the field of bleaching of hardwood kraft pulp. In this study, these two technologies are thoroughly investigated and compared with each other, and also with a reference standard ECF-sequence. A 2-stage bleaching sequence is also investigated. Interestingly, this latter sequence proves to offer superior results regarding many of the investigated parameters, not least bleaching chemical consumption to a given ISO brightness. Moreover, these investigations show that the results of hot acid treatment followed by a chlorine dioxide treatment without intermediate washing on the one hand and hot chlorine dioxide bleaching on the other differ markedly in terms e.g. of bleaching chemical consumption, bleaching yield and development of tensile strength. The hot chlorine dioxide bleaching offers many benefits compared to hot acid treatment followed by chlorine dioxide bleaching.

  • 119. Ragnar, M
    et al.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Hot chlorine dioxide bleaching and hot acid treatment - A comment2004Inngår i: Paperi ja puu, ISSN 0031-1243, Vol. 86, nr 3, s. 174-174Artikkel i tidsskrift (Annet vitenskapelig)
  • 120. Rahman, Hafizur
    et al.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Sandstrom, Peter
    Salmen, Lennart
    Engstrand, Per
    The effect of increased pulp yield using additives in the softwood kraft cook on the physical properties of low-grammage handsheets2017Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, nr 3, s. 317-323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of increasing the pulp yield by the addition of sodium borohydride (NaBH4) or polysulfide (PS) in softwood kraft cooking, i.e. enhancing the retention of glucomannan, on the physical properties of low-grammage handsheets was studied. In addition to the yield improvement, an increase in tensile index was observed, especially at lower degrees of beating. These higher yield pulps showed an increase in pore volume, indicating an increased degree of swelling of the fibres. Presumably, the increased flexibility of the fibres affects the bonding strength and leads to the higher tensile index observed.

  • 121. Salmen, Lennart
    et al.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. Innventia AB, Sweden.
    Improved pulp yield and strength by retained glucomannans in kraft pulping of softwood2015Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, nr 4, s. 584-590Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibilities of improving yield and strength properties of softwood bleached kraft pulps by retaining a higher content of glucomannan during kraft cooking using additives that decrease the rate of carbohydrate degradation were looked upon. In addition the effect of an increased alkaline concentration, favouring stopping reactions over peeling reactions was explored. Yield increases in the range of 2 to 4%-units were achieved using additives. In the case of the higher alkali charge instead a small yield decrease was noticed. Higher alkali charge in general resulted in a larger loss of xylan in the pulp. When examining the effects of the application of shearing forces at the end of the cook, mimicking industrial pulps, all cooks using high alkali conditions were affected by a large decrease in strength properties, both in tensile index and tear index as well as in fibre strength measured as re-wet Zero-span. For pulps cooked with polysulphide and H2S additions, stabilising the glucomannan degradation, the strength reductions were smaller than for the reference pulps. This resulted in pulps with both a higher yield and similar or better strength properties than those for the reference pulp. These pulps also had better beatability, i.e. the tensile strength increased faster during PFI-beating than for the reference pulp.

  • 122.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Forsström, A.
    Wackerberg, E.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Bleaching of eucalyptus kraft pulps with chlorine dioxide: Factors affecting the efficiency of the final D stage2012Inngår i: TAPPI Journal, ISSN 0734-1415, Vol. 11, nr 3, s. 43-53Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the bleaching efficiency of the final chlorine dioxide (D 2) stage in the D 0(EP)D 1D 2 bleaching sequence, focusing on the effect of pH in relation to the bleaching history of pulp samples. The samples used were unbleached kraft Eucalyptus grandis pulps with kappa no. 14.8 and the same pulp oxygen-delignified to kappa nos. 12 and 9.8. The samples were bleached according to the D 0(EP)D 1 sequence to a brightness of about 86% ISO and then submitted to the final D 2 stage under identical conditions (e.g., chlorine dioxide charge, time, temperature, and final pH). The target final brightness was 90.5% ISO. Changes in the kappa number, brightness, viscosity, and contents of hexenuronic acid, 4-O-methylglucuronic acid, and the total amount of carboxylic acid (COOH) groups in pulps were monitored during the bleaching sequence. The final brightness of eucalyptus kraft pulps increased when the terminal pH of the D 2 stage was raised from 3.0 to 6.5. The 90.5% ISO target brightness in the D 2 stage was achieved for all pulps within a pH range of 4.5-6.5, but this required adjusting final pH for individual samples. The optimal pH value with respect to pulp viscosity was between 3 and 5. Despite dissimilar conditions applied in previous bleaching stages, the samples after the D 1 stage revealed similar residual lignin contents as shown by kappa number analysis. The content of hexenuronic acid in the samples, however, varied broadly, from 2 to 26 mmol/kg. Conductometric titration showed different amounts of carboxylic acid groups in pulps after the D 1 stage, of which hexenuronic acid accounted for only a minor part. The variations in the fiber charge resulted from the different bleaching conditions applied before the D 2 stage. The fiber charge affected the alkali demand in the final D 2 stage, whereas variations in the alkali demand affected the initial pH and associated process kinetics. Lower total fiber charge was found to be beneficial for improved final brightening and viscosity when bleached at higher final pH. Application: This study will help pulp mill engineers to better understand how a pulp's oxidative history may affect the process kinetics in the final D bleaching stage. Fiber charge is important when selecting optimal pH for the final brightening of eucalyptus kraft pulps.

  • 123.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Forsström, A.
    Wackerberg, E.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Bleaching of eucalyptus kraft pulps with chlorine dioxide: Factors affecting the efficiency of the final D stage2011Inngår i: Int. Pulp Bleach. Conf., IPBC, 2011, s. 376-403Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The bleaching efficiency of the final D stage in the D 0(EP) D 1D 2 bleaching sequence was investigated focusing on the effect of pH in relation to the bleaching history of pulp samples. The pulps used were unbleached kraft Eucalyptus grandis pulps with a kappa number of 14.8, and the same pulp oxygen-delignified to kappa numbers 12 and 9.8. The samples were bleached according to the D 0(EP)D 1 sequence to a brightness of about 86% ISO and then submitted to the final D 2 stage under identical conditions. The target final brightness was 90.5% ISO. Changes in the kappa number, brightness, viscosity and contents of hexenuronic acid (HexA), 4-O-methylglucuronic acid and the total amount of carboxylic acid groups in pulps were monitored during the bleaching sequence. The target brightness in the D 2 stage was achieved for all pulps, but this required a different final pH for individual samples, indicating dissimilarities between chromophore types in them. In general, brightness increased as the pH increased from 3 to 6. The optimal value with respect to pulp viscosity was between pH 3 and 5. Despite unlike conditions applied in previous bleaching stages, the samples after the D 1 stage revealed similar residual lignin contents as shown by kappa number analysis. The content of hexenuronic acid in the samples was, however, found to vary broadly in the range from 2 to 26 mmol/kg. Conductometric titration showed different amounts of carboxylic (COOH) groups in pulps after the D 1 stage, of which HexA accounted for only a minor part. Since the content of 4-O-methylglucuronic acid groups was similar for all samples, the difference in the amount of COOH groups was mainly associated with oxidation of the residual lignin. Some of the charges might also originate from oxidized cellulose. It was concluded that the variations in the fiber charge result from the different bleaching conditions applied prior to the D 1 stage.

  • 124.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Forsström, Annbritt
    Eka Chemicals AB, Bohus.
    Wackerberg, Eva
    Eka Chemicals AB, Bohus.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Impact of bleaching sequence on the efficiency of final chlorine dioxide stage in ECF-type bleaching of eucalyptus kraft pulps2011Konferansepaper (Annet vitenskapelig)
  • 125.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Forsström, Annbritt
    Eka Chemicals AB, Bohus.
    Wackerberg, Eva
    Eka Chemicals AB, Bohus.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The final bleaching of eucalyptus kraft pulp with chlorine dioxide: what factors affecting its efficiency?2011Konferansepaper (Annet vitenskapelig)
  • 126.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Helander, Mikaela
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Chowdhury, Sudip
    Wedin, Helena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Kadla, John F.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Evaluation of physico-chemical properties and prediction of spinning parameters for high-quality lignins produced by ultra-filtration of industrial Kraft liquor2013Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245Artikkel i tidsskrift (Annet vitenskapelig)
  • 127.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Gellerstedt, Göran
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    The influence of a bleaching sequence on the brightness stability of eucalyptus kraft pulp2005Inngår i: Appita Annual Conference, 2005, s. 251-255Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the present research the influence of two bleaching sequences, D 0(EP)D1 (ECF-type) and Q1(OP)Q2(PO) (TCP-type), on the content of different oxidizable structures and metal ions in eucalyptus kraft pulp was studied in relation to the brightness stability of the pulp. It was shown that pulps bleached to full brightness with ECF- and TCF-type sequences contain differing amounts of oxidizable structures of carbohydrate origin, such as hexenuronic acid (HexA). These structures play a dominant role in the thermal yellowing of bleached kraft pulps and largely determine the yellowing kinetics. The most significant discoloration is observed for TCF-bleached pulps having an especially high content of HexA. The discoloration does not appear to be related to the presence of metal ions in pulps. There is a correlation between the HexA content and brightness stability of the bleached pulps. This correlation is due to reactions where HexA acts as a precursor in the formation of coloured compounds or intermediates which are then involved in the color formation. Furoic structures representing the main acid degradation products of HexA are suggested as the actual intermediates that cause yellowing by forming colored compounds.

  • 128.
    Sevastyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Gellerstedt, Göran
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Influence of the bleaching sequence on the brightness stability of eucalyptus kraft pulp2007Konferansepaper (Annet vitenskapelig)
  • 129.
    Sevasyanova, Olena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Helander, Mikaela
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Chowdhury, Sudip
    Lange, Heiko
    Wedin, Helena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Zhang, Liming
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Kadla, John F.
    Crestini, Claudia
    Lindström, Mikael F.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Tailoring the Molecular and Thermo-Mechanical Properties of Kraft Lignin by Ultrafiltration2014Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, nr 18, s. 9505-9515Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study has shown that ultrafiltration allows the selective extraction from industrial black liquors of lignin fraction with specific thermo-mechanical properties, which can be matched to the intended end uses. Ultrafiltration resulted in the efficient fractionation of kraft lignin according to its molecular weight, with an accumulation of sulfur-containing compounds in the low-molecular weight fractions. The obtained lignin samples had a varying quantities of functional groups, which correlated with their molecular weight with decreased molecular size, the lignin fractions had a higher amount of phenolic hydroxyl groups and fewer aliphatic hydroxyl groups. Depending on the molecular weight, glass-transition temperatures (T-g) between 70 and 170 degrees C were obtained for lignin samples isolated from the same batch of black liquor, a tendency confirmed by two independent methods, DSC, and dynamic rheology (DMA). The Fox-Flory equation adequately described the relationship between the number average molecular masses (M-n) and T-g's-irrespective of the method applied. DMA showed that low-molecular-weight lignin exhibits a good flow behavior as well as high-temperature crosslinking capability. Unfractionated and high molecular weight lignin (M-w > 5 kDa), on the other hand, do not soften sufficiently and may require additional modifications for use in thermal processings where melt-flow is required as the first step.

  • 130. Simeonova, Galya
    et al.
    Sjodahl, Ragnar
    Ragnar, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    On the effect of a xylanase post-treatment as a means of reducing the yellowing of bleached hardwood kraft pulp2007Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 22, nr 2, s. 172-176Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of an enzymatic post-treatment of bleached hardwood kraft pulp in order to improve the brightness stability was studied using two commercially available endoxylanases. The results clearly show that the yellowing was significantly reduced for two pulps of different origins bleached in different ways. The beneficial effect on the brightness stability was linked to a removal of hexenuronic acid (HexA) from the pulps. The practical applicability of the results needs to be considered in relation to the cost of the enzyme and to indications that there is some yield loss due to the treatment.

  • 131.
    Sjödahl, Ragnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Axelsson, Patrik
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Addition of Dissolved Wood Components to Improve the Delignification Rate and Pulp Yield in Hardwood Kraft Pulping2006Inngår i: Appita journal, ISSN 1038-6807, Vol. 59, nr 4, s. 317-320Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates the effects on the rate of delignification, HexA content and pulp yield of dissolved wood components (DWC) in the cooking liquor during the kraft pulping of Eucalyptus urograndis. The cooking was carried out with and without the addition of 50% DWC, in the form of black liquor, and also with and without the addition of a lignin-like model compound using a so-called constant composition cooking technique.

    The results show that the presence of DWC leads to an increase in the rate of delignification which makes it possible to reach kappa number 18 with an H-factor 40% less. Due to the faster delignification, 20% less HexA was formed at kappa number 18 when DWC was added than in the absence of added DWC. The presence of DWC also leads to a yield increase of up to two percentage points measured as lignin-free yield.

  • 132.
    Sjödahl, Ragnar
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    The Effect of Sodium Ion Concentration and Dissolved Wood Components in the Kraft Cook of Softwood2004Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 19, nr 3, s. 325-329Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of ionic strength and dissolved wood components (DWC) in form of industrial black liquor on the delignification rate and the brightness of the unbleached softwood kraft pulp has been investigated. A technique with a high liquor-to-wood ratio (75 L/kg) a so-called constant composition cook was used to separate the effects of the different parameters. The study showed that an increase in the ionic strength led to a decrease in the rate of delignification and gave a more coloured pulp, where as the presence of DWC gave a more coloured pulp and an increase in the delignification rate.

    The influence of the ionic strength and DWC on the bleachability of the softwood kraft pulp in an ECF-sequence (D(EOP)DD) was also investigated. The results show that the bleachability i.e. consumption of bleaching chemicals to reach a certain brightness, was not affected by the ionic strength during the cook. The addition of DWC, on the other hand, increased the consumption of bleaching chemicals to reach ISO brightness 89%.

  • 133.
    Sjödahl, Ragnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The influence of industrial black liquor on the delignification rate in the kraft cooking2007Inngår i: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 33, nr 4, s. 240-245Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of dissolved wood components in industrial black liquor on the rate of delignification in softwood kraft cooking has been studied The results show that, when industrial black liquor was added, the delignification rate increased significantly during the bulk phase and decreased during the residual phase. A softwood black liquor was fractionated with ceramic membranes with various cut-offs, to see the way the addition of various molecular weight fractions of the black-liquor lignin affected the delignification rate. The results show that the delignification rate is dependent more on the content of phenolic groups than on the size of the lignin fragments. However, a low molecular-weight lignin fraction has a higher content of phenolic groups than a high molecular-weight fraction does. These results may explain one reason for the positive effect of adding industrial black liquor to the bulk phase of a softwood kraft cook.

  • 134.
    Sjödahl, Ragnar G.
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Axelsson, Patrik
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Addition of dissolved wood components for improvement of delignification rate and pulp yield in hardwood Kraft pulping2004Inngår i: 2nd International Symposium on Technologies Of Pulping, Papermaking and Biotechnology on Fiber Plants, Proceedings / [ed] Jin, YC; Xie, HF, NANJING: NANJING FORESTRY UNIV , 2004, s. 123-126Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study have investigated the effects of dissolved wood components (DWC) in the cooking liquor on the rate of delignification, pulp yield and HexA content during kraft pulping of Eucalyptus Urograndis. The cooking was carried out with and without the addition of DWC, in form of black liquor, as well as with and without the addition of a lignin-like model compound using a,. so-called constant composition cooking technique. The results show that the presence of DWC causes a rate increase in the delignification which makes it possible to reach kappa number 18 with around 40% less H-factor compared to a cook performed with a very low amount of DWC. The presence of DWC also results in a yield increase of up to two percentage units measured as lignin free yield.

  • 135.
    Sjödahl, Ragnar G.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Danielsson, Sverker
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Addition of wood model components to kraft cooking to better understand the improvement in delignification rate caused by dissolved wood components2005Inngår i: Appita Conference and Exhibition: 59th Appita Annual Conference and Exhibition: Incorporating the 13th ISWFPC (International Symposium on Wood, Fibre and Pulping Chemistry), Auckland, New Zealand, 16-19 May 2005: Proceedings, Appita, Inc. , 2005, s. 365-368Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study different dissolved wood components (DWC) in the industrial black liquor and their effect on the delignification during the kraft cook has been investigated. The cooking were performed on softwood as well as hardwood to se different effects on the delignification rates. Different wood model components as well as treated black liquor components were added to the kraft cooking liquor. The results show that the phenolic groups in the black liquor lignin has a positive effect on the delignifiacation rate. It was also shown that surfactant had a positive effect on the delignification rate in systems with low amount of DWC. Furthermore, it was shown that a black liquor with a low amount of lignin i.e. mostly carbohydrates had a positive effect on the delignification rate. Cellulose and hemicellulos, on the other hand, did not seem to have any effect on the delignification rate.

  • 136.
    Sjödahl, Ragnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Influence of Dissolved Wood Components on the Defibration point in Hardwood Kraft PulpingManuskript (Annet vitenskapelig)
  • 137. Sjödahl, Ragnar
    et al.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The influence of different cooking parameters on the bleachability of softwood kraft pulp.2002Inngår i: Proceedings 7th European Workshop on Lignocellulosics and Pulp, 2002Konferansepaper (Fagfellevurdert)
  • 138. Snekkens, Vidar
    et al.
    Olsson, Krister
    Gustafsson, Lennart
    Mikael, Lindström
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Method for precipitating hemicellulose onto fibres for improved yield and beatability: Förfaringssätt för utfällning av hemicellulosa på fiber för förbättrat utbyte och malbarhet1998Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    A method for continuous cooking of lignocellulosic fibre material, comprising the steps of sequentially (a) in a first stage, impregnating the fibre material in an impregnation liquid comprising alkali metal hydroxide, and thereafter withdrawing (14, 514) a spent impregnation liquid; (b) in a second stage, cooking the fibre material in a cooking liquor comprising alkali metal hydroxide; and (c) in a third stage, adding (A), to said fibre material, a liquid which is rich in hemicellulose, said liquid preferably comprising at least a part (14a, 514a) of said withdrawn spent impregnation liquid. In a fourth stage (d), the fibre material is cooked in a cooking liquor comprising the liquid added in the third stage, whereby the fibre material is subjected to a retention time of at least 1 hour in said fourth stage.

  • 139. Stigsson, Lars
    et al.
    Lindström, Mikael
    Kvaerner Pulping AB.
    Metod i samband med impregnering och kokning av lignocellulosamaterial: Polysulfide pulping process1997Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention relates to a process for producing pulp from cellulosic fiber material with improved polysulfide regeneration alone or in combination with polysulfide cooking. The cellulosic fiber material is impregnated with polysulfide before cooking followed by extraction of spent cooking liquor. A portion of the spent cooking liquor is gasified to hydrogen sulphide and treated to form an acidic gas comprising hydrogen sulphide and carbon dioxide. The acidic gas is reacted under conditions providing a hot stream of elemental sulphur, said stream admixed with an alkaline liquor containing sulphide. An alkaline polysulfide liquor is thus formed which is added during cooking or impregnation. During cooking is a portion of the extracted spent cooking liquor recycled to the impregnation step and a desired polysulfide concentration in the impregnation step is maintained by adding polysulfide liquor.

  • 140. Strand, Helena
    et al.
    Ragnar, Martin
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Behandling av slutblekt massa med i ett milt alkaliskt syrgassteg för att reducera eftergulning: Method for treatment of bleached chemical pulp2005Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention concerns a treatment step for what is known as fully bleached cellulose pulp, which maintains a brightness that exceeds ISO 88. With the aim of reducing brightness reversion and also with the aim to a certain degree of achieving an increase in brightness, the fully bleached pulp is treated in a mild alkaline oxygen gas step. The tendency for brightness reversion expressed in PC number can be reduced by as much as 25-40%.

  • 141.
    Tagami, Ayumu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gioia, Claudio
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lauberts, Maris
    Latvian State Inst Wood Chem, 27 Dzerbenes Str, LV-1006 Riga, Latvia..
    Budnyak, Tetyana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Moriana, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Solvent fractionation of softwood and hardwood kraft lignins for more efficient uses: Compositional, structural, thermal, antioxidant and adsorption properties2019Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 129, s. 123-134Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work summarizes the impact of solvent fractionation on the chemical structure, antioxidant activity, heating values, and thermal and adsorption properties of industrial hardwood and softwood kraft lignins. The aim of the research was to develop a simple approach for obtaining lignin fractions with tailored properties for applications in certain materials. Four common industrial solvents, namely, ethyl acetate, ethanol, methanol and acetone, in various combinations, were found to be efficient for separating spruce and eucalyptus kraft lignins into fractions with low polydispersities. The ethanol fraction of spruce and the ethyl acetate fraction of eucalyptus afforded the highest yields. Gel-permeation chromatography analysis was used to evaluate the efficiency of the chosen solvent combination for lignin fractionation. The composition and structure of the lignin material was characterized by elemental analysis, analytical pyrolysis (Py-GC/MS/FID) and P-31 NMR spectro-scopy. The thermal properties of the lignin samples were studied using thermogravimetric analysis. Proximate analysis data (ash, volatile components, organic matter and fixed carbon) was obtained through the direct measurement of weight changes in each experimental curve, and the high heating values (in MJ/kg) were calculated according to equations suggested in the literature. The adsorption properties of fractionated kraft lignins were studied using methylene blue dye. The correlations observed between molecular weight, composition and functionality and the thermal, radical scavenging and adsorption properties of the lignin fractions provides useful information for selecting the appropriate solvent combinations for specific applications of lignin raw materials (including their use as antioxidants, biofuels or sorbents in water treatment processes).

  • 142.
    Tagami, Ayumu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. Nippon paper Industries Co., Ltd. .
    Zhao, Yadong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Dobele, Galina
    Latvian State Institute of Wood Chemistry.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi. KTH, Tidigare Institutioner (före 2005), Pappers- och massateknik.
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lignin-modified tunicate cellulose nanofiber (CNF)-starch composites: impact of lignin diversity on film performanceManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Lignin fractions having different molecular weights and varied chemical structures isolated from kraft lignins of both softwood and hardwood via a sequential solvent fractionation technique were incorporated into a tunicate cellulose nanofibers (CNF) - starch mixture to prepare 100% bio-based composite films. The aim was to investigate the correlation between lignin diversity and film performance. It was confirmed that lignin’s distribution in the films was dependent on the solvents used for fractionation (acetone > methanol > ethanol > ethyl acetate) and influenced the optical properties of the films. The -OH group content and molecular weight of lignin were positively related to film density. In general, the addition of lignin fractions led to the thermal stability decrease and the Young's modulus increase of the composite films. The modulus of the films was found to decrease as the molecular weight of lignin increased, and a higher amount of carboxyl and phenolic -OH groups in the lignin fraction resulted in films with higher stiffness. The thermal analysis showed higher char content formation for lignin-containing films in a nitrogen atmosphere with increased molecular weight. In an oxygen atmosphere, the phenol contents, saturated side chains and short chain structures of lignin had impacts on the maximum decomposition temperature of the films, confirming the positive relationship between the antioxidant ability of lignin and thermo-oxidative stability of the corresponding film. This study addresses the importance of lignin diversities on composite film performance, which could be helpful for tailoring lignin’s applications in bio-based materials based on their specific characteristics.

    Fulltekst (pdf)
    fulltext
  • 143.
    Tavast, Daniel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Brännvall, Elisabeth
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Selectiveness and efficiency of combined peracetic acid and chlorine dioxide bleaching stage for kraft pulp in removing hexeuronic acid2011Inngår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 45, nr 1-2, s. 89-95Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Combined peracetic acid and chlorine dioxide bleaching stages of unbleached and oxygen delignified hardwood and softwood kraft pulps were compared with conventional chlorine dioxide and peracetic acid stages as to kappa number and viscosity reduction, selectivity and reduction of hexenuronic acid content. The combined stages were more efficient in kappa number reduction than those with only chlorine dioxide. Part of the increased kappa number reduction was due to an improved degradation of hexenuronic acid. The stages where chlorine dioxide was added before the peracetic acid (DT) showed a higher selectivity than those in which the chemicals were added simultaneously (D+T); in turn, the latter were more efficient than the "pure" chlorine dioxide (D, D-0) and peracetic acid stages (T). However, peracetic acid and chlorine dioxide seemed to react with each other, leading to the degradation of both bleaching chemicals. The mechanisms and practical implementation of these bleaching sequences are discussed.

  • 144.
    Veguta, Vijaya Lakshmi
    et al.
    KTH. Innventia AB, Sweden.
    Stevanic, Jasna S.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Salmen, Lennart
    Thermal and Alkali Stability of Sodium Dithionite Studied Using ATR-FTIR Spectroscopy2017Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, nr 2, s. 2496-2506Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sodium dithionite (Na2S2O4) may have the potential to be used as a reducing agent for the stabilization of glucomannan in kraft cooking for increased pulp yield. However, due to the fact that dithionite decomposes under the conditions of kraft pulping, studies of the effects of dithionite in kraft pulping are non-conclusive; sometimes clearly showing an increased yield, and in other studies no effect at all. The specific conditions influencing dithionite degradation are also unclear. For that reason, this study was conducted to determine the thermal and chemical stability of sodium dithionite with respect to specific factors, such as the pH, temperature, heating time, and the concentration of sodium dithionite solution. The study was performed under anaerobic conditions using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The thermal and alkali stability of the sodium dithionite solution was shown to decrease with increasing temperature, heating time, and concentration of the solution at the alkaline conditions studied. The thermal stability decreased rapidly at weak alkalinity (pH 9) as well as in high alkalinity (pH 14), whereas the sodium dithionite was rather stable at moderate alkalinity (pH 11.5 to pH 13).

  • 145.
    Wang, Yan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Azhar, Shoaib
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Stabilisation of polysaccharides during alkaline pretreatment of wood combined with enzyme-supported extractions in a biorefinery2015Inngår i: Journal of wood chemistry and technology, ISSN 0277-3813, E-ISSN 1532-2319, Vol. 35, nr 2, s. 91-101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Specific enzymes have been demonstrated to increase the possibilities for extracting wood polymers. Enzymatic treatment requires an open wood structure, which was achieved by extended impregnation of the wood. However, some of the hemicelluloses, primarily glucomannan, and lignin were lost during the impregnation. To improve the carbohydrate yield, three glucomannan modification agents: sodium borohydride, polysulphide and anthraquinone, were used, which increased the yields of the impregnated materials from 76.6% to 89.6%, 81.3% and 80.0%, respectively. Through the use of additives, most of the glucomannan could be retained in the wood while still allowing the enzymes to penetrate the wood and attack the polymers. The additives also increased the extraction yield from 9 to 12% w/w wood. Gamanase treatment prior to the extraction increased the extraction yield to 14%. Of the three stabilising agents, sodium borohydride was the most efficient, providing the highest extraction yields.

    Fulltekst (pdf)
    Stabilisation of polysaccharides during alkaline pretreatment of wood combined with enzyme-supported extractions in a biorefinery
  • 146.
    Wang, Yan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Jedvert, Kerstin
    Chalmers University of Technology.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Theliander, Hans
    Chalmers University of Technology.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Dithionite impregnation combined with mild steam explosion of spruce wood – an improved version of kraft pulpingManuskript (preprint) (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Norway spruce (Picea abies) wood chips were impregnated with water or sodium dithionite (Na2S2O4) and were subsequently subjected to a mild steam explosion (STEX) treatment at four or seven bar for ten minutes. In order to evaluate the combined effect of Na2S2O4 and STEX, kraft cooking was performed on samples pre-treated with different combinations of impregnation and STEX. Carbohydrate composition, Klason lignin content, kappa number, intrinsic viscosity, pulp yield, brightness and tensile strength (on pulp sheets) were tested and compared. The results showed that an impregnation with Na2S2O4 combined with mild STEX had a good effect on the delignification during kraft pulping, shown by lower kappa numbers and lower Klason lignin content. The viscosity of the pulp samples of Na2S2O4 plus STEX was lower than the water impregnated and non-STEX pulps. However, the lower viscosity did not influence the strength of the pulp since the tensile index was still high. The Na2S2O4 plus STEX pulp sheets also showed the highest brightness value.

  • 147.
    Wang, Yan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Alkaline pretreatment to open the wood structure for enzymatic modification2011Inngår i: Proceedings of the 16th International Symposium of wood, fiber and pulp chemistry, 2011, s. 1041-1044Konferansepaper (Fagfellevurdert)
  • 148.
    Wang, Yan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Increased Degradability of Cellulose by Dissolution in Cold Alkali2014Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 4, s. 7566-7578Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To enhance the degradability of cellulosic materials for further industrial purposes, different qualities of cellulose were dissolved in cold sodium hydroxide solution and precipitated by lowering the pH with sulfuric acid. The precipitated cellulose was subjected to acidic and enzymatic hydrolysis. The results showed that the precipitated cellulose degraded considerably faster both with enzymes and acid relative to the untreated controls. Important pretreatment parameters that can influence the degradability of the pretreated cellulosic materials were found to include temperature and concentration of the cellulose in NaOH solution. Increasing amounts of cellulose were hydrolysed with decreasing pretreatment temperature; the degradability of the pretreated cellulose increased with decreasing cellulose concentration. The degree of polymerization (DP) also can influence the pretreatment efficiency. Diluted sulfuric acid was able to decrease the DP and enhance the effect of dissolution and precipitation. The results showed that the lower DP of cellulosic materials caused an increase of degradability for the NaOH pretreated samples compared to untreated samples. The NaOH pretreatment was more effective for shorter chain cellulose.

  • 149.
    Wang, Yan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Mild alkaline treatment activates spruce wood for enzymatic processing: A possible stage in bio-refinery processes2011Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, nr 3, s. 2425-2434Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The structure of wood is so compact that enzymes are too large to penetrate into the structure and thereby attack the wood components for modifications that can be valuable for various purposes. Here we present a pretreatment method based on traditional kraft pulping, which opens the wood structure, so that enzymes are able to attack the wood components. To study this kind of chemical pretreatment, spruce wood samples were treated at similar conditions used in kraft cooking at varying intensities (H-factors). To verify if the structure was "opened" for enzymes, the pretreated wood samples were incubated with a cellulolytic culture filtrate, and the released reducing sugar concentration after the enzymatic hydrolysis was measured. The results indicated that un-pretreated wood fibers could not be attacked by the enzymes, but already relatively mild pretreatment was sufficient for letting the culture filtrate attack wood polysaccharides, and more intensive treatments opened the structure further. The mildest treatments did not cause any significant yield losses of lignin (Klason lignin). Some galactoglucomannans were however lost during the pretreatments. The mechanisms behind the effect and the technical significance of the method are discussed.

  • 150.
    Wang, Yan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, Hans
    Chalmers University of Technology.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Improved yield and pulp properties by adding sodium dithionite in kraft pulping of spruceManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The reductive effect of sodium dithionite (Na2S2O4) on sugar model compounds was investigated. Results revealed that parts of open aldehyde forms in the sugars were reduced to the corresponding alditols by Na2S2O4. The possibilities to improve yield and other properties of spruce kraft pulp by addition of Na2S2O4 were also investigated. The yield, carbohydrate compositions, Klason lignin, intrinsic viscosity, kappa number of pulp, tensile strength and optical properties of resultant paper sheets were analysed. Compare with the normal kraft pulp without Na2S2O4 addition, yield together with viscosity were increased, while Klason lignin and kappa number were decreased. The brightness and tensile strength of paper sheet were also improved. The only drawback for adding sodium dithionite to white liquor was higher reject content. This could be overcome by pre-impregnation with Na2S2O4 before kraft pulping process. The possibility of applying Na2S2O4 in industrial kraft pulp mill was discussed, including how to generate Na2S2O4 from black liquor thereby closing the process.

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