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  • 1.
    Eivazihollagh, Alireza
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Metal-Chelate Complexes in Alkaline Solution: On Recovery Techniques and Cellulose-based Hybrid Material Synthesis2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    For decades, aminopolycarboxylate chelating agents have been extensively used in various industrial applications. The ability of chelating agents to form stable metal-chelate complexes is the main reason for using them to manage metal ions within water-based industrial processes. Considerable quantities of industrial effluent containing chelating agents and heavy metals are produced and often discharged into the environment. The toxicity of heavy metals and the non-biodegradability of the chelating agents, as well as their accumulation in the environment, has become cause for concern. The main purpose of this thesis was to evaluate and develop processes for recovery of chelated metal complexes from aqueous solution. In this regard, the membrane electrolysis technique was evaluated for recovery of copper and aminopolycarboxylic chelating ligands such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), and a surface-active derivative of DTPA, 2-dodecyldiethylenetriaminepentaacetic acid (C12-DTPA) from aqueous solution. By using this method, it was possible to simultaneously recover the chelating ligand for further reuse and collect the metals by electrodeposition, making the process more cost-effective and hindering the discharge of copper ions and chelating ligands as pollutants into the environment. In addition, the ion flotation technique with the chelating surfactant C12-DTPA could be employed to separate metal ions, especially from their dilute solutions, and concentrate them in a foam phase. This is because C12-DTPA has a purpose-built functionality; besides forming strong coordination complexes with metal ions, it is also surface-active and will readily adsorb at air-water interfaces. In this study, C12-DTPA was effectively used in combination with foaming agents for the removal of toxic metal ions such as Cd2+, Zn2+, and Sr2+ from aqueous solution using ion flotation. From an economical perspective, this method could be combined with the membrane electrolysis technique to recover metal and regenerate chelating surfactant so that it can be reused.

    The present work also shows the synthesis of metal and metal oxide(s) nanoparticles (NPs) in alkaline aqueous solution containing chelated metal ions, in order to fabricate metal NPs–cellulose hybrid materials. Cellulose is the most abundant renewable material, with good mechanical performance and chemical resistivity in a wide range of solvents, which makes it a promising material to support metal NPs. In this respect, we developed a rapid and inexpensive one-pot synthesis of spherical copper NPs in a cellulose matrix. The hybrid material displayed antibacterial properties for both the gram-negative and gram-positive bacteria. The synthesis was further developed by studying the influence of various chelating ligands and surfactants on the NPs’ morphology and chemical composition. According to the results, DDAO, a zwitterionic surfactant, was found to mediate the formation of pure octahedral Cu2O NPs. In addition, a hybrid material film composed of regenerated cellulose and synthesized Cu2O nano-octahedrons was fabricated by spin-coating.

  • 2.
    Eivazihollagh, Alireza
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svanedal, Ida
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    On chelating surfactants: Molecular perspectives and application prospects2019In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 278, p. 688-705Article in journal (Refereed)
    Abstract [en]

    Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.

  • 3.
    Göransson, Kristina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Tar/CH4 Reforming by Catalytic Bed Materials in a Biomass Fluidised Bed Gasifier2012In: 20th European Biomass Conference & Exhibition: Proceedings of the International Confernce held in Milano, Italy, 18 - 22 June 2012, 2012Conference paper (Other academic)
    Abstract [en]

    A study on in-bed catalytic material reforming of tar/methane (CH4) has been performed in the 150 kW allothermal biomass gasifier at Mid Sweden University (MIUN). The MIUN gasifier, built for research on synthetic fuel production, is a dual fluidised bed gasifier (DFBG). The syngas for automotive fuels synthesis has a strict specification of impurities. The biggest challenge for biomass fluidised-bed gasification is the reforming of tars and CH4. Internal reforming should be considered before downstream reforming. The MIUN gasifier has a unique design suitable for in-bed tar/CH4 catalytic reforming and continuously internal regeneration of the reactive bed material. The experimental tests are carried out in three cases: 1) basic condition with silica sand (no catalytic activity), 2) calcinated olivine, and 3) Fe-impregnated olivine (10%wtFe/Olivine Catalyst). The measurement results have been evaluated by comparing tar/CH4 content in the syngas from the gasifier operated under different operation conditions. These results in BFB mode have initiated the ongoing investigations of the catalytic effects and regeneration in DFB mode. It can be concluded that the Fe-impregnated olivine showed a surprising low reactivity for tar and CH4 reforming in the BFB model. 

  • 4.
    Hellström, Lisbeth
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Energy Efficiency Improvement Potential in TMP and CTMP by Axial Precompression of Wood During ChippingManuscript (preprint) (Other academic)
    Abstract [en]

    It has recently been shown that there is a possibillity to improve the energy efficiency during first stage TMP (thermomechanical pulp) refining by performing the wood chipping so as to increase the compressive damage in the chips and hence breaking up the wood structure. The parameter that was varied was the spout angle i.e. the angle between the fibre direction of the wood specimen and the cutting plane. In this article is investigated how the refining of chips produced at two different spout angles i.e. 30 and 50, influenced the properties of CTMP (chemithermomechanical pulp). It was found that the specific energyinput for a certain CSF (Canadian Standard Freeness) value was lower for chips produced at the spout angle of 50 but that the addition of chemicals (NaHSO3) to the dilution water had no influence on the specific energy value for a given CSF value. However, the tensile index and specific light scattering coefficient was substantially higher for handsheets made of the pulp refined from chips produced at the spout angle 50 and with NaHSO3 added compared to handsheets from pulp made from 30 and 50 chips without chemicals added.

  • 5.
    Hellström, Lisbeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gregersen, Øyvind
    Department for Chemical Engineering, NTNU, Norway.
    Evaluation Of Collimated Chipping Technology For Reducing Energy Consumption In Mechanical Pulping2012In: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 2, no 3, p. 6-9Article in journal (Refereed)
    Abstract [en]

    It has recently been shown that the energy efficiency during first-stage TMP (thermo-mechanical pulp) refining can be improved using amodified chipping method (collimated chipping), where the angle between the fibre direction of the wood specimen and the cutting plane is increased. This paper reports the differences in properties of TMP refined from wood chips produced at two different spout angles, 30° and 50°, with and without the addition of sodium bisulphite (NaHSO3) to the dilution water. It was found that the specific energy input for a certain CSF (Canadian Standard Freeness) value was lower for chips produced at spout 50°, but that the addition of chemicals to the dilution water had no influence on the specific energy value for a given CSF value. However, the tensile index and specific light-scattering coefficient were substantially higher for handsheets made from the pulp refined from chips produced at spout angle 50° and with NaHSO3 added compared to handsheets from pulp made from 30° and 50° chips without chemicals added.

  • 6.
    Hellström, Lisbeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    The effect on the energy consumption in mechanical pulping of different wood chipping conditions2010In: Proceedings of 7th International Seminar of Fundamental Mechanical Pulp Research (IFMPRS 2010), 2010, p. 124-126Conference paper (Other academic)
  • 7.
    Hellström, Lisbeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gregersen, Øyvind
    Department for Chemical Engineering, NTNU, Trondheim, Norway.
    Properties of wood chips for thermomechanical pulp (TMP) production as a function of spout angle2011In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 65, no 6, p. 805-809Article in journal (Refereed)
    Abstract [en]

    Spruce woodchipswere produced under well-controlled conditions in a laboratory woodchipper at spout angles of 30°, 40°, and 50° at a cutting rate of 20 m s-1 and with a nominalchip length of 25 mm. Thechips were then refined under thermomechanical pulp (TMP) conditions in a pilot refiner plant. The pulpproperties such as freeness, average fiber length, and shives content were determined and evaluated as a function of specific energy consumption. For a first stage refining and for a freeness value of 350 ml, a decrease in specific electrical energy consumption could be achieved by performing thewood chipping at a spout angle of 50° as compared to 30° which is the spout angle commonly used. A patent application regarding this method has been filed and is pending. It is realized that a freeness value is not directly indicative of any quality measure, such as, for example tensile index and light scattering coefficient but the obtained results can be interpreted to be promising. Further studies are needed regarding the impact of the modified chipping process.

  • 8.
    Henshaw Osong, Sinke
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Development of CTMP-based nanofibrillated Cellulose /nanographite composites for paper applications2015Conference paper (Other academic)
  • 9.
    Osong, Sinke Henshaw
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Development of nanofibrillated cellulose/nanographite composites for paper applications2015In: TAPPI International Conference on Nanotechnology for Renewable Materials 2015, TAPPI Press, 2015, Vol. 1, p. 35-55Conference paper (Refereed)
  • 10.
    Persson, Erik
    et al.
    Holmen Paper Development Center.
    Engstrand, Per
    Holmen Paper Development Center.
    Karlsson, Lennart
    Holmen Paper AB.
    Fredrik, Nilsson
    Holmen Paper AB.
    Wahlgren, Mikael
    Holmen Paper AB.
    Utilization of the natural variation in wood properties–a comparison between pilot plant and mill scale trials2003In: Proceedings of International Mechanical Pulping Conference, Quebec City, 2003, p. 83-90Conference paper (Refereed)
    Abstract [en]

    Four different pulpwood classes of Norway spruce (Picea abies (L.) Karst). were tested in mill scale production of TMP at Hallsta Papermill. The objectives of the trial were to evaluate both rather extreme and more traditional roundwood classes in a full-scale TMP-plant with respect to pulp properties and energy requirements. The experiment was partly based on the results from the proceeding pilot plant trial within the EuroFiber project. The results generally confirmed the findings in the pilot plant trial. Young wood with a high proportion of juvenile wood gave a pulp with attractive optical properties, but somewhat lower tear index and higher energy consumption. The other extreme, sawmill chips from old trees of heavy dimensions, required lower energy input and gave higher tear index, but inferior optical properties. The two more traditional classes gave pulps with properties between the two extremes.

  • 11.
    Sandin, Staffan
    et al.
    KTH.
    Cheritat, Alicia
    KTH.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cornell, Ann
    KTH.
    Deposition efficiency in the preparation of ozone-producing nickel and antimony doped tin oxide anodes2017In: Journal of Electrochemical Science and Engineering, ISSN 1847-9286, Vol. 7, no 1, p. 51-64Article in journal (Refereed)
    Abstract [en]

    The influence of precursor salts in the synthesis of nickel and antimony doped tin oxide (NATO) electrodes using thermal decomposition from dissolved chloride salts was investigated. The salts investigated were SnCl45H2O, SnCl22H2O, SbCl3and NiCl26H2O. It was shown that the use of SnCl45H20 in the preparation process leads to a tin loss of more than 85 %. The loss of Sb can be as high as 90 % while no indications of Ni loss was observed. As a consequence, theconcentration of Ni in the NATOcoating will be much higher than in the precursor solution. This high and uncontrolled loss of precursors during the preparation process will lead to an unpredictable composition in the NATOcoating and will have negative economic and environmental effects. It was found that using SnCl22H20 instead of SnCl45H2Ocan reduce the tin loss to less than 50 %. This tin loss occurs at higher temperatures than when using SnCl45H2Owhere the tin loss occurs from 56–147°C causingthe composition to change both during the drying (80–110°C) and calcination (460 -550 °C) steps of the preparation process. Electrodes coated with NATObased on the two different tin salts were investigated for morphology, composition, structure, and ozone electrocatalytic properties.

  • 12.
    Yang, Jiayi
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    pH-responsive cellulose–chitosan nanocomposite films with slow release of chitosan2019In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 6, p. 3763-3776Article in journal (Refereed)
    Abstract [en]

    Cellulose–chitosan films were preparedusing a physical method in which cellulose andchitosan were separately dissolved via freeze thawingin LiOH/urea and mixed in different proportions, theresulting films being cast and regenerated in water/ethanol. X-ray diffraction and Fourier transforminfrared spectroscopy (FT-IR) spectroscopy verifiedthe composition changes in the nanocomposites due todifferent mixing ratios between the polymers. Tensilestress–strain measurements indicated that the mechan-ical performance of the cellulose–chitosan nanocom-posites slightly worsened with increasing chitosancontent compared with that of films comprisingcellulose alone. Field emission scanning electronmicroscopy revealed the spontaneous formation ofnanofibers in the films; these nanofibers were subse-quently ordered into lamellar structures. Water uptakeand microscopy analysis of film thickness changesindicated that the swelling dramatically increased atlower pH and with increasing chitosan content, thisbeing ascribed to the Gibbs–Donnan effect. Slowmaterial loss appeared at acidic pH, as indicated by aloss of weight, and quantitative FT-IR analysisconfirmed that chitosan was the main componentreleased.Asample containing 75% chitosan reached amaximum swelling ratio and weight loss of 1500%and 55 wt%, respectively, after 12 h at pH 3. Thestudy presents a novel way of preparing pH-responsivecellulose–chitosan nanocomposites with slow-releasecharacteristics using an environmentally friendlyprocedure and without any chemical reactions.

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