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Brightness development of a hydrogen peroxide bleached spruce TMP. Comparisons of pre-treatments with DTPA and a separable chelating surfactant
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.ORCID iD: 0000-0002-0770-2086
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
SCA Rand D Centre, Box 716, SE-851 21 Sundsvall, Sweden.
Show others and affiliations
2012 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 1, 50-55 p.Article in journal (Refereed) Published
Abstract [en]

In this investigation a new type of recoverable complexing agent (chelating surfactant) has been compared with a conventional complexing agent; diethylenetriamine pentaacetic acid (DTPA), in the metal ion sequestering of thermomechanical pulps (TMP) to be hydrogen peroxide bleached. After different degrees of washing of the pulps, bleaching experiments at different total alkali charges were performed with and without sodium silicate additions, and the ISO brightness of hand-made sheets was measured. The residual hydrogen peroxide in the bleaching liquor was also determined. No significant difference in either the brightness development or the residual hydrogen peroxide content could be detected between the pulps treated with equivalent molar ratios of the different complexing agents. Furthermore, the recovery of the chelating surfactant-manganese complexes from laboratory made white water by froth flotation was also studied. Two different foaming agents; sodium dodecyl sulphonate (SDS) and dimethyldodecylamine oxide (DDAO), were tested in the froth generation. After an addition of 160 ppm of DDAO, more than 80% of the manganese chelates could be recovered in the foam, containing 3% of the initial water mass.

Place, publisher, year, edition, pages
2012. Vol. 27, no 1, 50-55 p.
Keyword [en]
Chelating surfactant; DTPA; Flotation; Hydrogen peroxide bleaching; Manganese; Thermomechanical pulp
National Category
Chemical Engineering
Identifiers
URN: urn:nbn:se:miun:diva-16093DOI: 10.3183/NPPRJ-2012-27-01-p050-055ISI: 000311019900006Scopus ID: 2-s2.0-84860145718OAI: oai:DiVA.org:miun-16093DiVA: diva2:516195
Available from: 2012-04-17 Created: 2012-04-17 Last updated: 2017-12-07Bibliographically approved
In thesis
1. REMOVAL OF LIPOPHILIC EXTRACTIVES AND MANGANESE IONS FROM SPRUCE TMP WATER BY FLOTATION
Open this publication in new window or tab >>REMOVAL OF LIPOPHILIC EXTRACTIVES AND MANGANESE IONS FROM SPRUCE TMP WATER BY FLOTATION
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Dissolved and Colloidal substances (DisCo) and metals are released from wood during thermomechanical pulp (TMP) production. The mechanical treatment causes that these components have a tendency to accumulate in process waters, as the water circulation systems in integrated paper mills are being closed. Disturbances such as pitch depositions on the paper machine (pitch problems), specks in the paper, decreased wet and dry strength, interference with cationic process chemicals, and impaired sheet brightness and friction properties appear in the presence of DisCo substances. The presence of transition metal ions such as manganese results in higher consumption of bleaching chemicals (hydrogen peroxide) and lowers the optical quality of the final product, and addition of complexing agents, such as EDTA or DTPA, to prevent this is needed. The never ending trends to decrease water consumption and increase process efficiency in pulp and paper production stress that it is very important both to know the effects of wood substances on pulping and papermaking and to be able to remove them in an efficient way.

Carried out investigations presented in this thesis show that the lipophilic extractives can be removed from TMP press water to high extent. A 90% decrease in turbidity and a 91% removal of lipophilic extractives from TMP press water can be obtained by addition of a cationic surfactant as foaming agent during flotation. Additionally, fibres located in TMP press water are not removed with the foam fraction but purified. A retained concentration of hydrophilic extractives in the process water indicates that the flotation is selective. Moreover, by introduction of a new recoverable surface active complexing agent, a chelating surfactant, manganese ions in the form of chelates can be successfully removed from the pulp fibres and separated from the process water in the same flotation process.

iii

The findings presented above indicate new possibilities for internal water cleaning and decreased emissions to water if flotation technology is applied in an integrated mechanical pulp mill.

Place, publisher, year, edition, pages
Sundsvall: Mittuniversitet, 2012. 50 p.
Series
Mid Sweden University licentiate thesis, ISSN 1652-8948 ; 74
Keyword
Flotation, Foaming agents, Chelating surfactant, TMP process water, Pitch control, Internal cleaning stage
National Category
Physical Chemistry
Identifiers
urn:nbn:se:miun:diva-16088 (URN)978-91-87103-01-8 (ISBN)
Presentation
2012-03-01, sal O102, Mid Sweden University, Sundsvall, 10:15 (English)
Opponent
Supervisors
Projects
ReGain/FORE
Available from: 2012-04-17 Created: 2012-04-17 Last updated: 2014-06-27Bibliographically approved
2. Fundamental Characterization and Technical Aspects of a Chelating Surfactant
Open this publication in new window or tab >>Fundamental Characterization and Technical Aspects of a Chelating Surfactant
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The purpose of this study was to investigate the fundamental characteristics of a chelating surfactant in terms of solution behaviour, chelation of divalent metal ions, and interaction in mixtures with different foaming agents and divalent metal ion, as well as examining its prospects in some practical applications. Chelating surfactants are functional molecules, with both surface active and chelating properties, which are water soluble and therefore suitable for chelation in many aqueous environments. The dual functionality offers the possibility to recover the chelating surfactant as well as the metals.

The DTPA (diethylenetriaminepentaacetic acid)-based chelating surfactant 4-C12-DTPA (2-dodecyldiethylenetriaminepentaacetic acid) was synthesized at Mid Sweden University. In the absence of metal ions, all eight donor atoms in the headgroup of 4-C12-DTPA are titrating and the headgroup charge can be tuned from +3 to -5 by altering the pH. The solution properties, studied by surface tension measurements and NMR diffusometry, were consequently found strongly pH dependent. pH measurements of chelating surfactant solutions as a function of concentration was used to extract information regarding the interaction between surfactants in the aggregation process.

Small differences in the conditional stability constants (log K) between coordination complexes of DTPA and 4-C12-DTPA, determined by competition measurements utilizing electrospray ionization mass spectrometry (ESI-MS), indicated that the hydrocarbon tail only affected the chelating ability of the headgroup to a limited extent. This was further confirmed in hydrogen peroxide bleaching of thermomechanical pulp (TMP) treated with 4-C12-DTPA.

Interaction parameters for mixed systems of 4-C12-DTPA and different foaming agents were calculated following the approach of Rubingh’s regular solution theory. The mixtures were also examined with addition of divalent metal ions in equimolar ratio to the chelating surfactant. Strong correlation was found between the interaction parameter and the phase transfer efficiency of Ni2+ ions during flotations. Furthermore, a significant difference in log K between different metal complexes with 4-C12-DTPA enabled selective recovery of the metal ion with the highest log K.

The findings in this study contribute to the understanding of the fundamental characteristics of chelating surfactants, which can be further utilized in practical applications.

Place, publisher, year, edition, pages
sundsvall: Mid Sweden University, 2014. 48 p.
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 179
Keyword
chelating surfactant, DTPA based surfactant, pH-responsive, characterization, surface tension, NMR diffusometry, conditional stability constants, interaction parameter, ion flotation
National Category
Physical Chemistry
Identifiers
urn:nbn:se:miun:diva-21405 (URN)978-91-87557-39-2 (ISBN)
Public defence
2014-03-21, Sal M102, Mittuniversitetet, sundsvall, 10:15 (English)
Opponent
Supervisors
Available from: 2014-02-20 Created: 2014-02-20 Last updated: 2014-02-20Bibliographically approved
3. Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
Open this publication in new window or tab >>Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Dissolved and Colloidal substances (DSC) and metals are released from woodduring thermomechanical pulp (TMP) production. These components have atendency to accumulate in process waters, as the water circulation systems inintegrated paper mills are closed. Disturbances such as pitch depositions in thepaper machine (pitch problems), specks in the paper, decreased wet and drystrength, interference with cationic process chemicals, and impaired sheetbrightness and friction properties appear when DSC are present. Transition metalions such as manganese results in higher consumption of bleaching chemicals(hydrogen peroxide) and lowers the optical quality of the final product, andaddition of complexing agents, such as EDTA or DTPA, to prevent this is needed.The never ending trends to decrease water consumption and increase processefficiency in pulp and paper production emphasizes that it is very important bothto know the effects of wood substances on pulping and papermaking and to beable to remove them in an efficient way. From a biorefinery point of view, DSCcomponents can be promising renewable raw materials for biofuels, bio‐basedchemicals and materials.In this thesis, a new approach using induced air flotation (IAF) without a cationicpolyelectrolyte addition for the removal of pitch and metal ions from mechanicalpulp mill process waters is presented. The induced air flotation of different processwaters is facilitated by the addition of a chelating surfactant and different foamingagents. The influence of the pH value, temperature and foaming agentconcentration on the flotation efficiency has been investigated. The investigations

presented show that the disturbing components can be removed from TMP presswater to a high extent. A 90% decrease in turbidity and a 91% removal of lipophilicextractives (i.e. resin and fatty acids, triglycerides, sterols and steryl esters) fromunbleached and bleached TMP process water can be obtained by addition of acationic surfactant as foaming agent during flotation. Lower amount of foamingagent is needed to purify efficiently bleached TMP process water, than unbleached.Additionally, fibres located in TMP press water are not removed with the foamfraction but purified. A retained concentration of hydrophilic extractives (i.e.hemicelluloses and lignans) in the process water indicates that the flotation isselective. Moreover, by introduction of a new recoverable surface activecomplexing agent, a chelating surfactant, manganese ions in the form of chelatescan be successfully removed from the pulp fibres and separated from the processwater in the same flotation process. Furthermore, from the purified unbleachedTMP process water a 90% recovery of dissolved hemicelluloses by anti‐solventprecipitation was obtained.The findings presented above indicate new possibilities for the internal watercleaning stage to decrease DSC emissions to recipient and for recovery of valuableraw materials from purified process water if flotation technology is applied in anintegrated mechanical pulp mill.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University, 2014. 178 p.
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 184
Keyword
flotation, foaming agents, chelating surfactant, TMP process water, pitch control, internal cleaning stage, hemicellulose recovery, anti‐solvents, solvents, precipitation
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:miun:diva-22244 (URN)978-91-87557-45-3 (ISBN)
Public defence
2014-05-28, O102, Holmgatan 10, Sundsvall, 12:33 (English)
Opponent
Supervisors
Projects
FORE
Funder
Knowledge Foundation, 2180
Available from: 2014-06-27 Created: 2014-06-23 Last updated: 2015-03-13Bibliographically approved

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