| 1. |
- Högberg, Ida, et al.
(författare)
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Brightness development of a hydrogen peroxide bleached spruce TMP. Comparisons of pre-treatments with DTPA and a separable chelating surfactant
- 2012
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:1, s. 50-55
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Högberg, Ida, et al.
(författare)
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Use of chelating surfactants as complexing agents for removal of manganese from mechanical pulp fibres prior to hydrogen peroxide bleaching.
- 2011
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Ingår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC. - Tianjin : China Light Industry Press. ; , s. 682-686
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Konferensbidrag (refereegranskat)abstract
- In this investigation a new type of recoverable complexing agent (chelating surfactant) has been compared with a conventional complexing agent (DTPA) in the metal ion management 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 surfactant-manganese complexes from laboratory made white water by foam flotation was also studied. Two different foaming agents, SDS and DDAO, were tested. After an addition of 160 ppm of the latter surfactant, about 80% of the manganese chelates could be recovered in the foam, containing 3% of the initial water mass.
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| 3. |
- Strand, Anders, et al.
(författare)
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Selective froth flotation of pitch components from spruce TMP process water
- 2012
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Ingår i: Appita journal. - 1038-6807. ; 65:4, s. 337-346
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Tidskriftsartikel (refereegranskat)abstract
- Selective removal of dissolved and colloidal pitch components from an unbleached thermomechanical pulp (TMP)pressate by addition of a cationic foaming agent, dodecyltrimethylammonium chloride (DoTAC), and subsequent frothflotation was assessed. The experiments were conducted with varying pH, temperature, and concentrations of DoTACand calcium. The concentrations of pitch components, lignans, and dissolved polysaccharides were determinedbefore and after flotation.All pitch components were removed more efficiently by flotation at pH 5 and 3.5 than by flotation at pH 7.6. Resinand fatty acids were removed to a higher degree than neutral pitch substances at all the tested pH levels. Most of thewater-soluble uronic acids and galactoglucomannans stayed in the TMP water after flotation.Froth flotation with DoTAC was an effective way of selectively removing colloidal and dissolved pitch. Removal of pitch,especially of resin acids, at an early stage should be beneficial to the overall papermaking process.
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| 4. |
- Yang, Jiayi, et al.
(författare)
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Biorefining of Spruce TMP Process Water : Selective Fractionation of Lipophilic Extractives with Induced Air Flotation and Surface Active Additive
- 2019
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 14:2, s. 4124-4135
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Zasadowski, Dariusz, et al.
(författare)
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Antisolvent precipitation of water-soluble hemicelluloses from TMP process water
- 2014
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 113, s. 411-419
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 6. |
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| 7. |
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| 8. |
- Zasadowski, Dariusz, et al.
(författare)
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Removal of dissolved and colloidal substances from mechanical pulping white waters by flotation
- 2011
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Ingår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC. - Tianjin : China Light Industry Press. ; , s. 1238-1242
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Various sorts of process water, foaming agents and a new chelating surfactant have been investigated in the chemical optimization of flotation ofwaters generated at laboratory and white water from mechanical pulping. Turbidity measurements, the Orcinol method for quantitative carbohydrate analysis and total organic carbon (TOC) as well as gas chromatography (GC) of extractives, have been carried out to determine theremoval and characteristics of Dissolved and Colloidal substances (DisCo). The tests have been realized under different conditions, such as using different flotation cells, foaming agents and complexing agents at different temperatures and pH values. It was found that a reduction of thewhite water turbidity of 70% and a 50% removal of the lipophilic substances from the white water can be obtained in a single-stage flotationunit, and that the selection of suitable flotation equipment, foaming agents and solution conditions plays a very important role in the removalcapacity of the unwished substances.
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| 9. |
- Zasadowski, Dariusz, 1980-
(författare)
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REMOVAL OF LIPOPHILIC EXTRACTIVES AND MANGANESE IONS FROM SPRUCE TMP WATER BY FLOTATION
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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.iiiThe 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.
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| 10. |
- Zasadowski, Dariusz, et al.
(författare)
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Removal of lipophilic extractives and manganese ions from spruce TMP waters in a customized flotation cell
- 2012
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Ingår i: BioResources. - 1930-2126. ; 7:2, s. 2376-2392
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Tidskriftsartikel (refereegranskat)abstract
- The influence of a chelating surfactant, different foaming agents, cationic polyelectrolytes, pH value, and temperature on the purification efficiency of process waters from a mechanical pulp mill has been studied by flotation in a 1 L customized unit. Turbidity measurements and gas chromatography (GC) were carried out to determine the removal and characteristics of dissolved and colloidal substances (DisCo). The manganese ion content in the process waters before flotation and the metal chelate removal capacity by flotation were determined by Inductively Coupled Plasma (ICP) and Atomic Absorption Spectrometry (AAS) measurements. It was found that a 99% removal of complex bound manganese ions and a 94% decrease in turbidity of the TMP water produced at the laboratory can be achieved in a single-stage flotation with a chelating surfactant and a foaming agent. Furthermore, a 91% decrease in turbidity, the removal of up to 96% of resin and fatty acids, and 93% of triglycerides from TMP water can be obtained after application of a foaming agent.
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