| 1. |
- Baena-Moreno, Francisco, 1992, et al.
(author)
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Effluents and residues from industrial sites for carbon dioxide capture: a review
- 2023
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In: Environmental Chemistry Letters. - : Springer Science and Business Media LLC. - 1610-3653 .- 1610-3661. ; 21:1, s. 319-337
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Research review (peer-reviewed)abstract
- The adverse effects of climate change calls for the rapid transformation of manufacturing processes to decrease the emissions of carbon dioxide. In particular, a lower carbon footprint can be achieved by capturing carbon dioxide at the site of emission. Here we review the use of industrial effluents, waste and residues to capture carbon dioxide. Waste include steelmaking slag, municipal solid waste incinerator ashes, combustion fly ash, black liquor, paper mill waste, mining waste, cement waste, construction and demolition waste, waste from the organic industry, and flue gas desulfurization gypsum waste. Capture capacities range from 2 to 800 kg of carbon dioxide per ton of waste, depending on processes, waste type and conditions. Cement waste and flue gas desulfurization gypsum waste show the highest capture capacity per ton of waste.
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| 2. |
- Carlstedt, Jonas, et al.
(author)
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Hydration and the phase diagram of acid hydrolyzed potato starch
- 2014
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In: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 112, s. 569-577
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Journal article (peer-reviewed)abstract
- We investigated hydration of acid hydrolyzed potato starch (maltodextrin) employing a multi-method approach. In particular, synchrotron radiation X-ray scattering and differential scanning calorimetry were used, and, for the first time, the material was investigated with sorption calorimetry and a newly developed quartz crystal microbalance with humidity scanning. The dry starch was found to be in an amorphous state. During hydration it exhibits a glass transition in both bulk and thin film samples, followed by an exothermic event where the starch crystallized. Recrystallized bulk samples displayed neither a pronounced glass transition nor crystallization upon hydration whereas both events occurred in thin film samples. The hydration-driven crystallization resulted in an X-ray pattern consistent with the coexistence of A and B type crystallites; however, at higher water concentrations only the B form occurred. The results were used to construct the first ever acid hydrolyzed starch–water phase diagram.
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| 3. |
- Carlstedt, Jonas, et al.
(author)
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Understanding Starch Gelatinization : the Phase Diagram Approach
- 2015
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In: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 129, s. 62-69
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Journal article (peer-reviewed)abstract
- By constructing a detailed phase diagram for the potato starch–water system based on data from optical microscopy, synchrotron X-ray scattering and differential scanning calorimetry, we show that gelatinization can be interpreted in analogy with a eutectic transition. The phase rule explains why the temperature of the gelatinization transition (G) is independent on water content. Furthermore, the melting (M1) endotherm observed in DSC represents a liquidus line; the temperature for this event increases with increasing starch concentration. Both the lamellar spacing and the inter-helix distance were observed to decrease with increasing starch content for starch concentrations between approximately 65 wt% and 75 wt%, while the inter-helix distance continued decreasing upon further dehydration. Understanding starch gelatinization has been a longstanding challenge. The novel approach presented here shows interpretation of this phenomenon from a phase equilibria perspective.
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| 4. |
- Leventaki, Emmanouela, 1996, et al.
(author)
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Experimental evaluation of black liquor carbonation for carbon dioxide capture
- 2023
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In: Journal of CO2 Utilization. - 2212-9820. ; 72
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Journal article (peer-reviewed)abstract
- Carbon dioxide is one of the main if not the most potent greenhouse gases responsible for climate change. Scientists put great efforts to tackle this problem and carbon dioxide capture seems to be a promising solution. The present study proposes a novel method of carbon dioxide capture using black liquor, a side stream from the paper and pulp industry. Its content in sodium hydroxide makes it an attractive candidate for carbon dioxide capture via carbonation. The black liquor was prepared from oat husks, a non-woody biomass, using the soda-pulping process. To estimate its carbon dioxide absorption capacity, a mixture of nitrogen and carbon dioxide (70:30%) was sparged into a bubble column reactor and computational fluid dynamics simulations of this setup were used to evaluate the mixing process. The formation of carbonate and bicarbonate ions throughout the carbonation process was followed using a Fourier-Transform Infrared (FTIR) probe and a pH meter. The absorption capacity was measured from the weight increase of the reactor. It was found to be around 30 g of carbon dioxide/L of black liquor. The carbonate and bicarbonate species in black liquor before and after carbonation were further characterized with 13C Nuclear Magnetic Resonance (NMR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and optical microscopy. Using industrial side-streams might enable an economically feasible process without the need for production of virgin absorbents or their recovery. Furthermore, this capturing process, which is performed at atmospheric conditions might reduce the overall energy consumption. The results demonstrated that black liquor could be an attractive absorbent for carbon dioxide, paving the way for a circular and resource-efficient economy.
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| 5. |
- Salam, Muhammad Abdus, 1983, et al.
(author)
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One-pot reductive liquefaction of sawdust to renewables over MoO x -Al 2 O 3 variants: insight into structure-activity relationships
- 2024
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In: Sustainable Energy and Fuels. - 2398-4902. ; 8:12, s. 2668-2681
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Journal article (peer-reviewed)abstract
- Valorization of forest residual products can offer a vital pathway to derive bio-based chemicals and fuel components. Herein, we report the effective and direct conversion of sawdust biomass over a supported Mo-oxide catalyst that results in a dominant fraction of aliphatic/cyclic alkanes and alkylbenzenes with low residual solids. The reductive liquefaction was conducted in an autoclave reactor using a series of MoOx-Al2O3 variants in the range of 340-400 °C with an initial H2 pressure of 35 bar for 4 h. At 340 °C, a correlation between Mo-loadings and reactivity for depolymerization and hydrodeoxygenation was found optimal for a surface density of 3.2 Mo-atoms per nm2 corresponding to 8 wt% Mo-loading. The liquefied fraction showed high selectivity (∼38%) for the formation of cycloalkanes and alkylbenzenes. At higher temperatures (400 °C) enhanced reactivity over the optimal catalyst showed higher cycloalkane and alkylbenzenes formation (∼57%) at a low biomass-to-catalyst feed mass ratio (3 : 1). At a higher ratio (10 : 1), alkylphenols (∼41%) are the leading product fraction followed by cycloalkanes and alkylbenzenes (∼34%) with a high liquefied monomer bio-oil product yield of 39.4 wt%. Catalyst characterization via XRD, Raman, H2-TPR, and XPS analysis revealed that the origin for this reactivity arises from the Mo species formed and stabilized over the support surface. A well dispersed, octahedral, higher fraction of easily reducible Mo-species (Mo5+) was evident over the optimal catalyst which enables enhanced C-O cleavage facilitating the hydrodeoxygenation reaction. Moreover, the solid residue yield could be reduced to below 5 wt% by optimizing the reaction conditions and particle size of the sawdust.
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| 6. |
- Wojtasz, Joanna, et al.
(author)
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Chemical pretreatment of wood chips : A comparative study of mild steam explosion and hot water extraction
- 2015
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In: 6th Nordic Wood Biorefinery Conference, NWBC 2015. - : VTT Technical Research Centre of Finland. - 9789513883539 ; , s. 341-347
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Conference paper (peer-reviewed)abstract
- Pretreatment of wood is a prerequisite for an efficient separation and utilization of its building blocks in future biorefinery concepts. Inherent recalcitrance of the cellulose-hemicellulose-lignin matrix of the cell wall poses huge challenges on separation of these components and implies usually a need for a broad set of methods targeting different components and providing as well chemical as morphological alterations. Mild steam explosion and hot water extraction are examples of typical pre-treatment methods enabling extraction of hemicelluloses and facilitating further processing of wood. Both are based on autohydrolysis of lignocellulosic material at high temperatures, but involve generally different conditions, the most prominent difference being a rapid disintegrating discharge employed in the steam explosion treatment, rendering morphological changes and altering structure accessibility compared to the physically less disruptive hot-water extraction. In this study we compare the key features of both of these methods and present that their effects on wood are somewhat non-uniform.
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| 7. |
- Wojtasz, Joanna, et al.
(author)
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Hydration and swelling of amorphous cross-linked starch microspheres
- 2016
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In: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 135, s. 225-233
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Journal article (peer-reviewed)abstract
- Hydration of cross-linked starch microspheres, commercially available as a medical device, was investigated using a multi-method approach. We found that the uptake of water is accompanied by substantial swelling and changes of the polymer structure. Sorption calorimetry provided information about thermodynamics of water sorption, revealed presence of isothermal glass transition and absence of hydration-induced crystallization, observed in non-cross linked starch material. The changes in the surface and bulk properties of microspheres at different water–starch concentrations were investigated using synchrotron radiation X-ray scattering and analyzed using concept of fractals. The obtained information, combined with the results of differential scanning calorimetry, was used to construct a phase diagram of the studied material. Finally, hydration induced evolution of polymer structure revealed by the X-ray scattering was linked to the changes observed during swelling with optical microscopy.
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| 8. |
- Wojtasz-Mucha, Joanna, et al.
(author)
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Dissolution of wood components during hot water extraction of birch
- 2021
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In: Wood Science and Technology. - : Springer Science and Business Media Deutschland GmbH. - 0043-7719 .- 1432-5225. ; 55:3, s. 811-835
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Journal article (peer-reviewed)abstract
- Autohydrolysis-based pretreatments enable extraction of hemicellulose from wood tissue prior to the paper pulp cooking processes enabling their further use as platform chemicals and in material applications. In this study, hot water extraction of birch meal was conducted in a small flow-through system. The combination of high surface area of the milled material with increased driving force induced by constant flow of freshwater, together with fast evacuation of extract, enabled a detailed study of the dissolution process. Based on the findings, deeper insight into acidification and autohydrolysis progress was obtained.
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| 9. |
- Wojtasz-Mucha, Joanna, 1989, et al.
(author)
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Dissolution of wood components during hot water extraction of spruce
- 2023
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In: Tappi Journal. - 0734-1415. ; 22:5, s. 329-343
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Journal article (other academic/artistic)abstract
- The purpose of this study was to investigate the autohydrolysis of softwood, which is the main chemical operation in both hot water extraction and steam explosion. Control of the process and monitoring its course were ensured by the careful choice of experimental setup and conditions: a milled spruce material was extracted in a small flow-through reactor to minimize degradation of the dissolved material and to enable analysis of the resulting liquors extracted at selected time points. The obtained liquid and solid fractions were analyzed for sugar composition and acetic acid concentration. The results showed that partially degraded hemicelluloses were extracted; hemicelluloses side chains were cleaved off and detected as monomers, while deacetylation was limited. Chain scissions of cellulose were observed as a result of autohydrolysis.
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| 10. |
- Wojtasz-Mucha, Joanna, 1989, et al.
(author)
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Dissolution of wood components during hot water extraction of spruce
- 2023
-
In: Tappi Journal. - 0734-1415. ; 22:5, s. 329-343
-
Journal article (peer-reviewed)abstract
- The purpose of this study was to investigate the autohydrolysis of softwood, which is the main chemical operation in both hot water extraction and steam explosion. Control of the process and monitoring its course were ensured by the careful choice of experimental setup and conditions: a milled spruce material was extracted in a small flow-through reactor to minimize degradation of the dissolved material and to enable analysis of the resulting liquors extracted at selected time points. The obtained liquid and solid fractions were analyzed for sugar composition and acetic acid concentration. The results showed that partially degraded hemicelluloses were extracted; hemicelluloses side chains were cleaved off and detected as monomers, while deacetylation was limited. Chain scissions of cellulose were observed as a result of autohydrolysis.
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| 11. |
- Wojtasz-Mucha, Joanna, 1989, et al.
(author)
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Hydrothermal pretreatment of wood by mild steam explosion and hot water extraction
- 2017
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In: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 241, s. 120-126
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Journal article (peer-reviewed)abstract
- The aim of this work was to compare the two most common hydrothermal pre-treatments for wood – mild steam explosion and hot water extraction – both with the prospect of enabling extraction of hemicelluloses and facilitating further processing. Although both involve autohydrolysis of the lignocellulosic tissue, they are performed under different conditions: the most prominent difference is the rapid, disintegrating, discharge employed in the steam explosion opening up the structure. In this comparative study, the emphasis was placed on local composition of the pre-treated wood chips (of industrially relevant size). The results show that short hot water extraction treatments lead to significant variations in the local composition within the wood chips, while steam explosion accomplishes a comparably more even removal of hemicelluloses due to the advective mass transport during the explosion step.
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| 12. |
- Wojtasz-Mucha, Joanna, 1989
(author)
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Mild Steam Explosion of Wood and Forest Residues in the Perspective of a Materials Biorefinery
- 2019
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Licentiate thesis (other academic/artistic)abstract
- The main objective of this work was to explore the prospects of using mild steam explosion as a pretreatment step in a forest based material biorefinery. During the steam explosion saturated steam is applied to the biomass at elevated pressure leading to an autohydrolysis of the lignocellulosic tissue, which is followed by a rapid pressure discharge, disintegrating and opening up the structure. As a consequence, the pretreatment enables the extraction of the most sensitive hemicelluloses and facilitates further processing, e.g. enzymatic treatment and chemical pulping. To investigate the effects rendered by the pretreatment, it was performed on two different types of forest biomass: Norway spruce wood chips and forest residues of mixed origin. The focus was on investigating the effects on the chemical structure of the material. In order to gain improved understanding of the fundamental mechanisms behind the pretreatment, the local effects on the composition of the wood tissue pretreated using steam explosion were investigated and compared with those accomplished by hot water extraction. Furthermore, cooking experiments were performed on pretreated forest residues to evaluate how the changes rendered by the pretreatment affect further processing of the material. The effects of the steam explosion were evaluated in terms of compositional analysis, molecular weight distribution and structural changes of extracted material (lignin and hemicelluloses). The results show that, due to the advective mass transport during the explosion step, steam explosion accomplishes a more even removal of hemicelluloses from the pretreated wood chips compared to the hot water extraction. Moreover, the impact of the steam explosion was found to be limited when material of a smaller size, namely refined forest residues, was pretreated.
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| 13. |
- Wojtasz-Mucha, Joanna, 1989
(author)
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Pre-Extraction of Wood Components Mild hydrothermal methods for a future materials biorefinery
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Today there is an increasing urgency in discovering new, and more sustainable, replacements for fossil-based materials and chemicals. The biorefinery concept is promising in this context in that it relies on transforming biomass into a spectrum of commercial products. Wood is the primary bioresource in Scandinavia. It is mostly processed in the kraft pulping process used in the huge and important pulp and paper industry, thereby providing a suitable platform for future material biorefineries. This process allows for the efficient separation of lignin and cellulose, along with the option of adding a pretreatment step for the recovery of hemicelluloses. Among existing pretreatments, mild hydrothermal methods, such as hot water extraction and steam explosion, are promising since they allow recovery of hemicelluloses with minimal degradation. They are based on the acidic hydrolysis (autohydrolysis) of wood components and diffusive transport through the wood tissue. In steam explosion, the latter is enhanced by the advective transport in the pore system of the wood caused by the rapid release of the pressure. The focus of this work was to explore the possibility of using steam explosion and hot water extraction on different types of forest biomass, as well as to improve understanding of the underlying mechanisms. Performed in different experimental set ups, the work included determining the local composition of wood chips pretreated in different ways, continuous extraction of spruce and birch wood meal and a stepwise treatment of forest residues. The influence of autohydrolysis on the wood components, hemicelluloses (decreasing molar weight, deacetylation, cleavage of side groups, extraction and degradation), lignin (partial degradation and extraction) and cellulose (introduction of chain scissions) was analyzed. Moreover, the mechanism of acidification and the contribution of acetic acid were also investigated. The variations in the local composition of the wood chips obtained by steam explosion and hot water extraction were determined and related to the differences in mass transport and severity of the treatment. Finally, it was shown that the impact of steam explosion had a limited effect on refined wood residues, likely due to the relatively small size of the material.
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| 14. |
- Wojtasz-Mucha, Joanna, et al.
(author)
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Pretreatment and cooking of forest residues
- 2019
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In: BioResources. - : North Carolina State University. - 1930-2126. ; 14:4, s. 9454-9471
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Journal article (peer-reviewed)abstract
- The aim of this work was to investigate the possibility of processing forest residues by chemical delignification preceded by mild steam explosion. The focus was on using soda pulping, due to its simplicity. Kraft cooking was used for comparison to improve the understanding of the separation of the complex yet promising resource. The raw material consisted of chipped branches, bark, and twigs of mixed hardwood and softwood. Analysis of the raw material proved to be challenging due to the presence of a substantial fraction of extractives. Analysis of the pulps showed that the forest residue delignification was faster than that of wood. The effects of steam explosion were evaluated with the help of composition analysis, gel permeation chromatography (GPC) for the molecular weight of lignin, and NMR for the changes in its structure. The impact of steam explosion was found to be limited, possibly due to the relatively small size of the material.
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