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Hellström, Pia
Alternative names
Publications (6 of 6) Show all publications
Hellström, P., Heijnesson-Hulten, A., Paulsson, M., Håkansson, H. & Germgård, U. (2016). A comparative study of enzymatic and Fenton pretreatment applied to a birch kraft pulp used for MFC production in a pilot scale high-pressure homogenizer. TAPPI Journal, 15(6), 375-381
Open this publication in new window or tab >>A comparative study of enzymatic and Fenton pretreatment applied to a birch kraft pulp used for MFC production in a pilot scale high-pressure homogenizer
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2016 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 15, no 6, p. 375-381Article in journal (Refereed) Published
Abstract [en]

Microfibrillated cellulose (MFC) was produced in pilot scale from a bleached birch (Betula verrucosa) kraft pulp that was pretreated with either Fenton's reagent or with a combined mechanical and enzymatic method used at the Centre Technique du Papier (CTP; Grenoble, France). The change in fiber fibrillation during the homogenization treatment was monitored by analyzing the fiber and the fines content, size fractionation, rheological properties and visualization by light-and scanning electron microscopy (SEM). The Fenton pretreatment resulted in MFC suspensions that contained a high amount of small sized elements. After five passes through the high-pressure homogenizer, the amount of particles smaller than 20 mu m was 37% for the Fenton pretreated MFC compared to 13% for the enzymatically (endoglucanase) pretreated MFC. Altogether, the Fenton pretreatment enabled preparation of MFC with a higher degree of fibrillation after the same number of passes through the high-pressure homogenizer. Another option is to produce MFC of the same amount of fibrillation as after an enzymatic stage, but at significantly lower energy consumption.

Place, publisher, year, edition, pages
TAPPI Press, 2016
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-46239 (URN)000380267900004 ()
Available from: 2016-09-21 Created: 2016-09-21 Last updated: 2020-06-26Bibliographically approved
Hellström, P. (2015). Fenton Pre-treatment of a Birch Kraft Pulp for MFC preparation. (Licentiate dissertation). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Fenton Pre-treatment of a Birch Kraft Pulp for MFC preparation
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a fully bleached birch (Betula verucosa) kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment with a monocomponent endoglucanase (FiberCare® R). The mechanical treatment to MFC was performed in a laboratory colloid mill or in a pilot high-pressure homogeniser and the pre-treated pulps as well as the produced MFCs were chemically and morphologically characterised. Additionally, the MFCs produced in the colloid mill were evaluated as strength enhancers in test sheets representing the middle ply of paperboard.

From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. The increase in carbonyl groups could not be explained by the formation of new reducing end groups due to depolymerisation which indicates that carbonyl groups are introduced along the cellulose chain. The enzymatic pre-treatment as performed in this study caused less impact on the cellulosic material, i.e. resulted in a pulp with a higher DP and a much lower amount of carbonyl- and carboxylic groups compared with the Fenton pre-treated pulps. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically i.e. reached a higher specific surface area and a higher surface charge at a given mechanical treatment time compared to enzymatic pre-treated pulps and pulps not subjected to any pre-treatment. These findings were confirmed when MFCs were produced by homogenisation at high pressure in multiple passes; the birch kraft pulp was either pre-treated with Fenton’s reagent or the combined mechanic and enzymatic pre-treatment methodology used at the Centre Technique du Papier (CTP, France). By size fractionation, rheological measurements and scanning electron microscopy, it was revealed that Fenton pre-treatment resulted in MFC suspension containing a significantly higher proportion of small sized material (< 0.2 mm).

When the MFCs were evaluated as strength enhancers in test sheets produced from a furnish consisting of a spruce (Picea abies) chemithermomechanical pulp, MFC and a retention system containing cationic starch and an anionic silica sol, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition.

Abstract [en]

The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a bleached birch kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment. Additionally, the MFCs evaluated as strength enhancers in test sheets representing the middle ply of paperboard.

From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically indicating a potential to lower the energy consumption.

When the MFCs were evaluated as strength enhancers in test sheets, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs at a given mechanical treatment time. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2015
Series
Karlstad University Studies, ISSN 1403-8099 ; 2015:6
Keywords
Microfibrillated cellulose, Fenton chemistry, carbonyl groups, surface charge, total charge, Enzymatic hydrolysis, Tensile strength, z-directional strength
National Category
Chemical Sciences
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-34770 (URN)978-91-7063-617-2 (ISBN)
Presentation
2015-02-05, 9C204, Karlstads universitet, Karlstad, 10:15 (Swedish)
Opponent
Supervisors
Available from: 2015-01-30 Created: 2014-12-12 Last updated: 2020-06-30Bibliographically approved
Hellström, P., Heijnesson-Hulten, A., Paulsson, M., Håkansson, H. & Germgård, U. (2014). Fenton pre-treated microfibrillated cellulose evaluated as a strength enhancer in the middle ply of paperboard. Nordic Pulp & Paper Research Journal, 29(4), 732-740
Open this publication in new window or tab >>Fenton pre-treated microfibrillated cellulose evaluated as a strength enhancer in the middle ply of paperboard
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2014 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 4, p. 732-740Article in journal (Refereed) Published
Abstract [en]

Microfibrillated celluloses (MFCs), produced by various pre-treatments of a fully bleached birch kraft pulp, were evaluated as strength enhancers in test sheets representing the middle ply of paperboard. The furnish consisted of hydrogen peroxide bleached high temperature spruce chemithermomechanical pulp (HT-CTMP), MFC and a retention system containing cationic starch and an anionic silica sol. The MFC was prepared via a mechanical treatment in a colloid mill after pretreatment with Fenton's reagent, monocomponent endoglucanase or acidic hydrogen peroxide. Addition of 5% MFC, produced with Fenton pre-treatment, resulted in improved HT-CTMP properties with respect to increased tensile index (similar to 35%), z-directional strength (similar to 50%), tensile stiffness index (similar to 25%) compared to HT-CTMP test sheets prepared without MFC addition. The strength improvement was linearly correlated to the density of the tests sheet, to the surface area (BET) and to the surface charge of the enzymatic or chemically pre-treated MFCs.

Keywords
Microfibrillated cellulose, Fenton's reagent, Enzymatic hydrolysis, Tensile strength, Z-directional strength, Bending stiffness index, Bending resistance, Dewatering
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-41572 (URN)000346146900020 ()
Available from: 2016-04-25 Created: 2016-04-11 Last updated: 2020-06-26Bibliographically approved
Hellström, P., Heijnesson-Hulten, A., Paulsson, M., Hakansson, H. & Germgård, U. (2014). The effect of Fenton chemistry on the properties of microfibrillated cellulose. Cellulose, 21(3), 1489-1503
Open this publication in new window or tab >>The effect of Fenton chemistry on the properties of microfibrillated cellulose
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2014 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 3, p. 1489-1503Article in journal (Refereed) Published
Abstract [en]

A fully bleached birch kraft pulp was treated with acidic hydrogen peroxide in the presence of ferrous ions (Fenton's reagent) and thereafter treated mechanically in a colloid mill to produce a product containing microfibrillated cellulose (MFC). The produced MFC products were chemically and morphologically characterized and compared with MFC products produced without pretreatment as well as with enzymatic hydrolysis. Fenton treatment resulted in an increase in total charge and number of carbonyl groups while the intrinsic viscosity decreased. The Fenton treated pulps were easier to process mechanically i.e. they reached a higher specific surface area at a given mechanical treatment time and the MFC produced had a stable water-fibre suspension for at least 8 weeks compared to enzymatic pretreated pulps and pulps not subjected to any pretreatment.

Place, publisher, year, edition, pages
Springer, 2014
Keywords
Microfibrillated cellulose, Fenton chemistry, Enzymatic hydrolysis, Carbonyl groups, Carbohydrate composition, Total and surface charge, Suspension stability
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-41526 (URN)10.1007/s10570-014-0243-1 (DOI)000336322800036 ()
Available from: 2016-04-25 Created: 2016-04-11 Last updated: 2022-05-10Bibliographically approved
Walter, K., Paulsson, M. & Hellstrom, P. (2013). Acid Hydrogen Peroxide Treatment of Norway Spruce TMP: A Model Study Using Free Ferrous Ions and Ferric Ions Chelated with EDTA as Catalysts. Journal of wood chemistry and technology, 33(4), 267-285
Open this publication in new window or tab >>Acid Hydrogen Peroxide Treatment of Norway Spruce TMP: A Model Study Using Free Ferrous Ions and Ferric Ions Chelated with EDTA as Catalysts
2013 (English)In: Journal of wood chemistry and technology, ISSN 0277-3813, E-ISSN 1532-2319, Vol. 33, no 4, p. 267-285Article in journal (Refereed) Published
Abstract [en]

The acid hydrogen peroxide system has been evaluated in more detail in the presence of a coarse Norway spruce thermomechanical pulp (TMP). The effects of parameters on the reactions involved were determined, such as pH, retention time, pulp consistency, type of iron catalyst, and the amount of dissolved organic material. Residual hydrogen peroxide, chemical oxygen demand, dissolved iron, and total fiber charge were quantified and the hydroxyl radical activity was monitored. The results showed that a catalyst of free ferrous ions (Fe2+) gave more reactions with the lignocellulosic material than ferric ions (Fe3+) chelated with EDTA. Furthermore, there were somewhat more reactions with the TMP when there was less dissolved organic material in the liquid phase from the start. Hydroxyl radicals were detected in all cases, but the level differed depending on the conditions used. It is likely that the iron must bind with the TMP or be in close proximity for the hydroxyl radicals to react with the pulp.

Keywords
Hydrogen peroxide, TMP, Fenton's reagent, hydroxyl radicals, EDTA, COD, total fiber charge
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-38574 (URN)10.1080/02773813.2013.792840 (DOI)000320098800004 ()
Available from: 2015-11-30 Created: 2015-11-23 Last updated: 2017-12-01Bibliographically approved
Hellström, P., Heijnesson- Hultén, A., Paulsson, M., Håkansson, H. & Germgård, U. (2013). The effect of Fenton chemistry on the properties of microfibrillated cellulose (MFC).
Open this publication in new window or tab >>The effect of Fenton chemistry on the properties of microfibrillated cellulose (MFC)
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2013 (English)Other (Other academic)
Keywords
Fenton, microfibrillated cellulose
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-29181 (URN)
Available from: 2013-09-25 Created: 2013-09-25 Last updated: 2020-06-26Bibliographically approved
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