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Yang, J., Zasadowski, D., Edlund, H. & Norgren, M. (2019). Biorefining of Spruce TMP Process Water: Selective Fractionation of Lipophilic Extractives with Induced Air Flotation and Surface Active Additive. BioResources, 14(2), 4124-4135
Open this publication in new window or tab >>Biorefining of Spruce TMP Process Water: Selective Fractionation of Lipophilic Extractives with Induced Air Flotation and Surface Active Additive
2019 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 2, p. 4124-4135Article in journal (Refereed) Published
Abstract [en]

Lignocellulose biomass plays an important role in reducing thedependency on fossil fuels and ameliorating the dire consequences ofclimate change. It is therefore important that all the components oflignocellulose biomass are exploited. These components includehemicelluloses and extractives that are liberated and sterically stabilizedduring the thermomechanical pulping and that form the dissolved andcolloidal substance (DCS) in the process water. Biorefining of this processwater can extract these substances, which have a number of promisingapplications and can contribute to the full exploitation of lignocellulosebiomass. This paper presents a simple treatment of unbleached Norwayspruce (Picea abies) process water from TMP (thermomechanical pulping)production using induced air flotation (IAF) and cationic surfactant,dodecyl trimethylammonium chloride (DoTAC) to refine the extractivesand prepare the waters so that hemicellulose could be easily harvested ata later stage. By applying 80 ppm of DoTAC at a pH of 3.5 and 50 °Cbefore induced air flotation, 94% of the lipophilic extractives wererecovered from process water. Dissolved hemicellulose polysaccharideswere cleansed and left in the treated process water. The process enabledefficient biorefining of lipophilic extractives and purification of the processwater to enable more selective harvesting of hemicelluloses in subsequentsteps.

Keywords
Biorefining; Lipophilic extractives; Thermomechanical pulping; Induced air flotation
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-35955 (URN)10.15376/biores.14.2.4124-4135 (DOI)000466449000115 ()2-s2.0-85071077339 (Scopus ID)
Projects
EU Reginal fund 2
Funder
European Regional Development Fund (ERDF)
Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-09-03Bibliographically approved
Yang, J., Dahlström, C., Edlund, H., Lindman, B. & Norgren, M. (2019). pH-responsive cellulose–chitosan nanocomposite films with slow release of chitosan. Cellulose (London), 26(6), 3763-3776
Open this publication in new window or tab >>pH-responsive cellulose–chitosan nanocomposite films with slow release of chitosan
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2019 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 6, p. 3763-3776Article in journal (Refereed) Published
Abstract [en]

Cellulose–chitosan films were preparedusing a physical method in which cellulose andchitosan were separately dissolved via freeze thawingin LiOH/urea and mixed in different proportions, theresulting films being cast and regenerated in water/ethanol. X-ray diffraction and Fourier transforminfrared spectroscopy (FT-IR) spectroscopy verifiedthe composition changes in the nanocomposites due todifferent mixing ratios between the polymers. Tensilestress–strain measurements indicated that the mechan-ical performance of the cellulose–chitosan nanocom-posites slightly worsened with increasing chitosancontent compared with that of films comprisingcellulose alone. Field emission scanning electronmicroscopy revealed the spontaneous formation ofnanofibers in the films; these nanofibers were subse-quently ordered into lamellar structures. Water uptakeand microscopy analysis of film thickness changesindicated that the swelling dramatically increased atlower pH and with increasing chitosan content, thisbeing ascribed to the Gibbs–Donnan effect. Slowmaterial loss appeared at acidic pH, as indicated by aloss of weight, and quantitative FT-IR analysisconfirmed that chitosan was the main componentreleased.Asample containing 75% chitosan reached amaximum swelling ratio and weight loss of 1500%and 55 wt%, respectively, after 12 h at pH 3. Thestudy presents a novel way of preparing pH-responsivecellulose–chitosan nanocomposites with slow-releasecharacteristics using an environmentally friendlyprocedure and without any chemical reactions.

Keywords
Cellulose dissolution, Chitosan dissolution, pH responsive, Gibbs–Donnan equilibrium, Nanocomposite, Slow release
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-35778 (URN)10.1007/s10570-019-02357-5 (DOI)000464849500011 ()2-s2.0-85062686323 (Scopus ID)
Funder
Swedish Research Council Formas, 942-2015-251
Available from: 2019-03-12 Created: 2019-03-12 Last updated: 2019-09-03Bibliographically approved
Yang, J., Duan, J., Zhang, L., Lindman, B., Edlund, H. & Norgren, M. (2016). Spherical nanocomposite particles prepared from mixed cellulose–chitosan solutions. Cellulose (London), 23(5), 3105-3115
Open this publication in new window or tab >>Spherical nanocomposite particles prepared from mixed cellulose–chitosan solutions
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2016 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 5, p. 3105-3115Article in journal (Refereed) Published
Abstract [en]

Novel cellulose–chitosan nanocomposite particles with spherical shape were successfully prepared via mixing of aqueous biopolymer solutions in three different ways. Macroparticles with diameters in the millimeter range were produced by dripping cellulose dissolved in cold LiOH/urea into acidic chitosan solutions, inducing instant co-regeneration of the biopolymers. Two types of microspheres, chemically crosslinked and non-crosslinked, were prepared by first mixing cellulose and chitosan solutions obtained from freeze thawing in LiOH/KOH/urea. Thereafter epichlorohydrin was applied as crosslinking agent for one of the samples, followed by water-in-oil (W/O) emulsification, heat induced sol–gel transition, solvent exchange, washing and freeze-drying. Characterization by X-ray photoelectron spectroscopy, total elemental analysis, and Fourier transform infrared spectroscopy confirmed the prepared particles as being true cellulose–chitosan nanocomposites with different distribution of chitosan from the surface to the core of the particles depending on the preparation method. Field emission scanning electron microscopy and laser diffraction was performed to study the morphology and size distribution of the prepared particles. The morphology was found to vary due to different preparation routes, revealing a core shell structure for macroparticles prepared by dripping, and homogenous nanoporous structure for the microspheres. The non-crosslinked microparticles exhibited a somewhat denser structure than the crosslinked ones, which indicated that crosslinking restricts packing of the chains before and under regeneration. From the obtained volume-weighted size distributions it was found that the crosslinked microspheres had the highest median diameter. The results demonstrate that not only the mixing ratio and distribution of the two biopolymers, but also the morphology and nanocomposite particle diameters are tunable by choosing between the different routes of preparation.

Keywords
cellulose, chitosan, nanocomposite, microspheres, regeneration
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-28551 (URN)10.1007/s10570-016-1029-4 (DOI)000382634300026 ()2-s2.0-84982883552 (Scopus ID)
Note

First Online: 05 August 2016

Available from: 2016-08-17 Created: 2016-08-17 Last updated: 2019-09-03Bibliographically approved
Zasadowski, D., Yang, J., Edlund, H. & Norgren, M. (2014). Antisolvent precipitation of water-soluble hemicelluloses from TMP process water. Carbohydrate Polymers, 113, 411-419
Open this publication in new window or tab >>Antisolvent precipitation of water-soluble hemicelluloses from TMP process water
2014 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 113, p. 411-419Article in journal (Refereed) Published
Abstract [en]

During the thermomechanical pulping (TMP) of spruce, hemicelluloses (mainly galactoglucomannans, GGMs) are released into the process water at relatively low concentrations that are currently impossible to efficiently recover. This paper examines the recovery of hemicelluloses precipitated from TMP process water via solubility reduction by adding antisolvents such as methanol, ethanol, and acetone. The phase separation was monitored by turbidity measurements. Gravimetric analysis, FTIR, GC–MS, UV spectroscopy, and ICP-OES were used to determine the yield, purity, and composition of the precipitates. Gel permeation chromatography and pulsed field-gradient self-diffusion NMR were used to measure the molecular mass distribution of the precipitates. Acetone was found to be the most efficient antisolvent, giving the highest yield at the lowest addition. The contents of lipophilic extractives and lignin impurities were below 0.5% and 1.6%, respectively, and the metal content was approximately 2% in the precipitates obtained with acetone.

Keywords
Antisolvent precipitation, Flotation, Hemicelluloses, Process water, Recovery, Thermomechanical pulping
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-22315 (URN)10.1016/j.carbpol.2014.07.033 (DOI)000343613000052 ()2-s2.0-84907321202 (Scopus ID)
Available from: 2014-06-27 Created: 2014-06-27 Last updated: 2017-12-05Bibliographically approved
Yang, J., Norgren, M. & Edlund, H. (2013). Selective separation of wood substances from TMP mill process water by flotation. Analysis of the foam fraction.. In: : . Paper presented at The 17th International Symposium on Wood, Fiber and Pulping Chemistry.
Open this publication in new window or tab >>Selective separation of wood substances from TMP mill process water by flotation. Analysis of the foam fraction.
2013 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-20751 (URN)
Conference
The 17th International Symposium on Wood, Fiber and Pulping Chemistry
Available from: 2013-12-17 Created: 2013-12-17 Last updated: 2013-12-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5178-367x

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