umu.sePublications
Change search
Refine search result
1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Anugwom, Ikenna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku FI-20500, Finland.
    Rujana, L.
    Wärnå, J.
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku FI-20500, Finland.
    In quest for the optimal delignification of lignocellulosic biomass using hydrated, SO2 switched DBU MEASIL switchable ionic liquid2016In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 297, p. 256-264Article in journal (Refereed)
    Abstract [en]

    In this paper, various process parameters aiming at optimal short-time-high-temperature (STHT) process were studied upon fractionation of Nordic woody biomass into its primary constituents. Highly diluted, aqueous 'SO2-switched' switchable ionic liquid (SIL) based on an alkanol amine (monoethanol amine, MEA) and an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) was applied. The ultimate goal was to develop a more sustainable, environmentally friendly and cost efficient systems for efficient separation of the lignocellulosic fractions. One of the main products from the SIL fractionation is cellulose-rich pulp with very low lignin content, complemented with hemicelluloses. The NMR results reveal that substantial removal of lignin occurs even when relatively low amount of SIL was used. Further, a simple mathematical model describing the dissolution of the lignocellulose components (hemicellulose and lignin) and weight loss of wood as a function of time is described. Moreover, the most efficient process involved the use of SpinChem (R) rotating bed reactor while upon use of a flow through (loop) reactor, promising results were obtained at a treatment time of 4 h. Still, all the reactor systems studied gave rise to a rather low removal of hemicelluloses which mean that the solvent system is primary selective towards lignin dissolution.

  • 2. Berglund, Linn
    et al.
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Aitomäki, Yvonne
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Oksman, Kristiina
    Switchable ionic liquids enable efficient nanofibrillation of wood pulp2017In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 8, p. 3265-3279Article in journal (Refereed)
    Abstract [en]

    Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.

  • 3. Duan, Ran
    et al.
    Westerlind, Bo S.
    Norgren, Magnus
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Finland.
    Virtanen, Pasi
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Finland.
    Fibre Stress-Strain Response of High-Temperature Chemi-Thermomechanical Pulp Treated with Switchable Ionic Liquids2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 8570-8588Article in journal (Refereed)
    Abstract [en]

    The removal of lignin from a high-temperature chemi-thermomechanical pulp (HT-CTMP) using a switchable ionic liquid prepared from an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)), monoethanol amine (MEA), and SO2 was investigated. The objective was to measure the fibre properties before and after removal of the lignin to analyse the contributions from lignin in the HT-CTMP fibre to the tensile properties. It was found that the fibre displacement at break - measured in zero span, which is related to fibre strain at break - was not influenced by the lignin removal in this ionic liquid system when tested dry. There was a small increase in displacement at break and a reduction in tensile strength at zero span when tested after rewetting. At short span, the displacement at break decreased slightly when lignin was removed, while tensile strength was almost unaffected when tested dry. Under rewetted conditions, the displacement at break increased and tensile strength decreased after lignin removal. Nevertheless, no dramatic differences in the pulp properties could be observed. Under the experimental conditions, treatment with the ionic liquid reduced the lignin content from 37.4 to 15.5 wt%.

  • 4. Eta, Valerie
    et al.
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo akademi.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo akademi.
    Catalysis for carbon dioxide activation2013In: Catalysis in Finland: an exciting pathway, Oulu: Finnish Catalysis Society , 2013, , p. 428Chapter in book (Other academic)
  • 5.
    Khokarale, Santosh G.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Lappeenranta University of Technology.
    Mäki-Arvela, P.
    Virtanen, P.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo Akademi.
    Switchable polarity liquids2018In: Polymerized ionic liquids / [ed] Ali Eftekhari, London: Royal Society of Chemistry, 2018, p. 143-179Chapter in book (Other academic)
    Abstract [en]

    In this chapter, the synthesis and characterization, as well as applications, of various types of switchable polarity solvents (SPSs) are summarized in order to unravel their composition and switchable nature. The polarity 'switch' between a molecular liquid and ionic species in the case of SPSs is described on the basis of interactions occurring for various types of organic bases or silylamines with acid gases such as CO2 or SO2 and in the absence or presence of alcohols. The chapter consists of two principal parts where the synthesis of SPS systems is described as a result of interaction of one or two molecular components with acid gases. The molecular liquids in two-component SPSs comprise organic superbases such as 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) or 1,1,3,3-tetramethylguanindine (TMG or its derivatives) and lower to higher alcohols or water or glycerol. The one-component system involves the use of silylamines for SPS synthesis. The change in the composition and polarity of the reaction mixture during the synthesis, as well as the switchable nature of these SPSs, is demonstrated by gravimetric, spectroscopic and conductivity measurements. In the second part, various applications of SPS systems are described along with how the special characteristics of SPSs can be utilized.

  • 6. Pezoa-Conte, R.
    et al.
    Leyton, A.
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    von Schoultz, S.
    Paranko, J.
    Mäki-Arvela, P.
    Willför, S.
    Muszynski, M.
    Nowicki, J.
    Lienquedo, M. E.
    Pekka-Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Deconstruction of the green alga Ulva rigida in ionic liquids: closing the mass balance2015In: Algal Research, ISSN 2211-9264, Vol. 12, p. 262-273Article in journal (Refereed)
    Abstract [en]

    Algae are known to grow at high rates compared to terrestrial plants that contain comparable amounts of carbohydrates by weight. Therefore, this renders them attractive in terms of any biorefinery concept. In this work the green alga Ulva rigida, containing 40 wt.% of carbohydrates was pretreated with a switchable ionic liquid (SIL), distillable ionic liquid (DIL) and low-viscosity ionic liquid (LVIL). The SIL DBU–MEA–SO2 was prepared from a mixture of mono-ethanolamine (MEA) and 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) that was coupled with sulfur dioxide (SO2), whereas the DIL [TMGH+][EtCO2] (1,1,3,3-tetramethylguanidine propionate) was synthesized by a simple acid–base neutralization reaction. Consequently, the LVIL [HDBU+][5OF] protonated 1,8-diazabicyclo-[5,4,0]-undec-7-ene- 2,2,3,3,4,4,5,5-octafluoro-1-pentoxide was used as received. The treatments were carried out in the temperature range of 100–160 °C for 6 h. The products obtained after the treatments were analyzed using different techniques like ICP, OES, SEM, TEM, TGA, FTIR and carbohydrate determination by GC. Upon treatment with DIL up to 67 wt.% of carbohydrates could be dissolved. For the first time, processing of U. rigida was carried out in ionic liquids so that the mass balance of the process was obtained. It can be concluded that 1,1,3,3-tetramethylguanidine propionate shows significant potential when aiming at releasing carbohydrates from algal biomass that, consequently, can be applied in the production of platform chemicals and/or biofuels such as bioethanol.

  • 7. Ravanal, María Cristina
    et al.
    Pezoa-Conte, Ricardo
    von Schoultz, Sebastian
    Hemming, Jarl
    Salazar, Oriana
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jogunola, Olatunde
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mäki-Arvela, Päivi
    Willför, Stefan
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo/Turku, Finland.
    Lienqueo, María Elena
    Comparison of different types of pretreatment and enzymatic saccharification of Macrocystis pyrifera for the production of biofuel2016In: Algal Research, ISSN 2211-9264, Vol. 13, p. 141-147Article in journal (Refereed)
    Abstract [en]

    In this work, the brown algae Macrocystis pyrifera were pretreated with dilute sulfuric acid, water and three different types of ionic liquids (ILs): 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH][OAc]) and 1,8-diazabicyclo-[5.4.0]–undec-7-ene–sulfurdioxide–monoethanolamine (DBU–MEA–SO2–SIL), to disassemble the complex polysaccharide structure. After each pretreatment procedure, enzymatic saccharification was performed to release the monosaccharides. The main building blocks of M. pyrifera were processed by derivatization via acid methanolysis and subjected to gas chromatographic analysis. It was found that the main constituents were alginate (60.6 wt.%) and cellulose (22.6 wt.%) of total carbohydrate content. The degradation of alginate requires the action of alginate lyase and oligoalginate lyase, which hydrolyze the main chain in a synergistic mechanism releasing uronic acid (unsaturated uronate). Upon saccharification of cellulose, cellulases and β-glucosidase were used allowing the release of glucose. It was found that the best pretreatment strategy for M. pyrifera consisted of a pretreatment with 2 vol.% sulfuric acid, followed by saccharification of cellulose with a mixture of cellulases at pH 5.2 for 4 h at 50 °C or by saccharification of alginate with the enzyme lyase/oligoalginate lyase at pH 7.5 for 2 h at 37 °C. The process resulted in a release of 68.4 wt.% of glucose (55.74 ± 0.05 mg glucose/g algae) whereas in the case of alginate 85.8 wt.% of uronic acid (193.7 ± 10.6 mg uronic acid/g algae) was released. To the best of our knowledge this is the first time that saccharification of both cellulose and alginate from brown algae is reported.

  • 8.
    Rogne, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Anugwom, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Real-time 31P NMR investigation on the catalytic behavior of the enzyme Adenylate kinase in the matrix of a switchable ionic liquid2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 2, p. 3764-3768Article in journal (Refereed)
    Abstract [en]

    The integration of highly efficient enzymatic catalysis with the solvation properties of ionic liquids for an environmentally friendly and efficient use of raw materials such as wood requires fundamental knowledge about the influence of relevant ionic liquids on enzymes. Switchable ionic liquids (SIL) are promising candidates for implementation of enzymatic treatments of raw materials. One industrially interesting SIL is constituted by monoethanol amine (MEA) and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) formed with sulfur dioxide (SO2) as the coupling media (DBU-SO2-MEASIL). It has the ability to solubilize the matrix of lignocellulosic biomass while leaving the cellulose backbone intact. Using a novel 31P  NMR-based real-time assay we show that this SIL is compatible with enzymatic catalysis because a model enzyme, adenylate kinase, retains its activity in up to at least 25 wt % of DBU-SO2-MEASIL. Thus this SIL appears suitable for, for example, enzymatic degradation of hemicellulose.

  • 9.
    Soudham, Venkata Prabhakar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Raut, Dilip Govind
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Anugwoma, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Brandberg, Tomas
    Larsson, Christer
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Coupled Enzymatic Hydrolysis and Ethanol Fermentation: Ionic Liquid Pretreatment for Enhanced Yields2015In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 8, article id 135Article in journal (Refereed)
    Abstract [en]

    Background

    Pretreatment is a vital step upon biochemical conversion of lignocellulose materials into biofuels. An acid catalyzed thermochemical treatment is the most commonly employed method for this purpose. Alternatively, ionic liquids (ILs), a class of neoteric solvents, provide unique opportunities as solvents for the pretreatment of a wide range of lignocellulose materials. In the present study, four ionic liquid solvents (ILs), two switchable ILs (SILs) DBU–MEA–SO 2 and DBU–MEA–CO 2 , as well as two ‘classical’ ILs [Amim][HCO 2 ] and [AMMorp][OAc], were applied in the pretreatment of five different lignocellulosic materials: Spruce (Picea abies) wood, Pine (Pinus sylvestris) stem wood, Birch (Betula pendula) wood, Reed canary grass (RCG, Phalaris arundinacea), and Pine bark. Pure cellulosic substrate, Avicel, was also included in the study. The investigations were carried out in comparison to acid pretreatments. The efficiency of different pretreatments was then evaluated in terms of sugar release and ethanol fermentation.

    Results

    Excellent glucan-to-glucose conversion levels (between 75 and 97 %, depending on the biomass and pretreatment process applied) were obtained after the enzymatic hydrolysis of IL-treated substrates. This corresponded between 13 and 77 % for the combined acid treatment and enzymatic hydrolysis. With the exception of 77 % for pine bark, the glucan conversions for the non-treated lignocelluloses were much lower. Upon enzymatic hydrolysis of IL-treated lignocelluloses, a maximum of 92 % hemicelluloses were also released. As expected, the ethanol production upon fermentation of hydrolysates reflected their sugar concentrations, respectively.

    Conclusions

    Utilization of various ILs as pretreatment solvents for different lignocelluloses was explored. SIL DBU–MEA–SO 2 was found to be superior solvent for the pretreatment of lignocelluloses, especially in case of softwood substrates (i.e., spruce and pine). In case of birch and RCG, the hydrolysis efficiency of the SIL DBU–MEA–CO 2 was similar or even better than that of DBU–MEA–SO 2 . Further, the IL [AMMorp][OAc] was found as comparably efficient as DBU–MEA–CO 2. Pine bark was highly amorphous and none of the pretreatments applied resulted in clear benefits to improve the product yields.

1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf