Browsing by Subject "PULP"

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  • Virtanen, Tiina; Parkkila, Petteri; Koivuniemi, Artturi; Lahti, Jussi; Viitala, Tapani; Kallioinen, Mari; Mänttäri, Mika; Bunker, Alex (2018)
    Adsorptive fouling, by phenolic compounds, is a serious issue regarding the development and use of membrane based filtration technologies for water purification and wastewater treatment. We have developed a novel, combined, protocol of Raman spectroscopy and surface plasmon resonance (SPR) experiments, along with molecular dynamics (MD) simulation, to study the interaction of vanillin, a model phenolic compound, with the polyethersulfone (PES) surface of a membrane. The adsorption of vanillin to the PES surface was found to be highly pH dependent; the source of this was determined, by MD simulation, to be the stronger interaction with the protonated form of vanillin, predominant at low pH. Vanillin interacts with the PES surface, both through entropy driven, hydrophobic, interactions and, for the case of the protonated form, H-bonding of the hydroxyl group with the sulphur oxygens of the PES molecules. In addition to general insight into the fouling process that can be used to develop new methods to inhibit adsorptive fouling, our results also elucidate the specific interaction of the PES membrane with vanillin that can be used in the development of anti-fouling coatings, based on the structure of vanillin.
  • Mikkonen, Kirsi S.; Kirjoranta, Satu; Xu, Chunlin; Hemming, Jarl; Pranovich, Andrey; Bhattarai, Mamata; Peltonen, Leena; Kilpeläinen, Petri; Maina, Ndegwa; Tenkanen, Maija; Lehtonen, Mari; Willför, Stefan (2019)
    Wood biorefining currently involves large-scale industrial processes where a notable portion of raw materials, namely hemicelluloses and lignin, are either lost with the process water, degraded, or burnt for energy. Value added utilization of polymeric hemicelluloses is challenging due to their intermediate molar mass and the presence of other wood components, such as phenolic residues or wood extractives. Oil-in-water (O/W) emulsions represent a diverse and abundant class of applications in which the natural properties of wood hemicelluloses are beneficial. In the current work, we present highly promising new technical alkyd paint emulsion systems stabilized with hardwood glucuronoxylans (GX) and softwood galactoglucomannans (GGM). Samples from three isolation methods and their further fractionation by ethanol precipitation were systematically compared with regard to hemicellulose composition, interfacial activity, and functionality in emulsions. Emulsification of alkyd resins was successful with both GX and GGM obtained by various biorefining strategies. The highest emulsion stability over storage was achieved using crude non-purified GX and GGM fractions, and was correlated with the presence of phenolic compounds and extractives, interfacial activity, and small droplet size. Hardwood GX and softwood GGM are envisioned as natural emulsifiers of alkyd O/W emulsions, which are examples of diverse and abundantly-used technical dispersions. This study can be utilized as a guideline for targeted extraction of hemicelluloses with desired functionality, and as a protocol for developing environmentally-compatible industrial dispersions.
  • Lu, FeiFei; Kozak, Robert; Toppinen, Anne Maarit Kristiina; D'amato, Dalia; Wen, Zuomin (2017)
    With the international community's increasing concern for social and environmental problems, the fulfilment and disclosure of corporate social responsibility (CSR) has been advocated and promoted across the world. Forestry companies, which are particularly sensitive to environmental and social issues, are increasingly developing and improving their levels of CSR disclosure. However, information on emerging country contexts is still lacking. To fill this gap, this study focuses on Chinese forestry companies' CSR disclosure and introduces new disclosure indices through content analysis of annual reports by listed companies between 2011 and 2015. It then builds a correlation analysis of the factors influencing these companies' disclosure indices in order to gain a better understanding of the current situation for CSR implementation by forestry companies in emerging economies like China. Although context-specific, our findings can provide a reference for researchers and policy makers, and promote sustainable development via improved CSR disclosure by forestry companies, especially in developing regions.
  • Kirjoranta, Satu; Knaapila, Antti; Kilpelainen, Petri; Mikkonen, Kirsi S. (2020)
    Wood is an abundant and sustainable source of emerging food ingredients, namely hemicelluloses that fulfil a number of requirements for functional hydrocolloids. Hemicelluloses, especially spruce galactoglucomannans (GGM) and birch glucuronoxylans (GX), have potential to be used as stabilizers in various foods such as yogurts, beverages, dressings, and desserts. However, in addition to good technological functionality, safety, and low price, the applicability and market potential of new hydrocolloids is determined by their sensory properties. The present study reports, for the first time, the sensory profile of spruce GGM and birch GX in food. Sensory profiles from generic descriptive analysis of GGM- and GX-rich extracts, processed by spray drying or ethanol precipitation, were compared in three types of model food systems: water solutions, yogurt with solutions, and yogurt with emulsions stabilized by GGM or GX. Gum Arabic was included for comparison with a commercial ingredient known to have a mild flavor. The results showed that GGM and GX have a woody flavor, which can be reduced by ethanol precipitation and, in yogurt, masked by other food ingredients.
  • Laaksonen, Tiina; Helminen, Jussi K. J.; Lemetti, Laura; Långbacka, Jesper; del Cerro, Daniel Rico; Hummel, Michael; Filpponen, Ilari; Rantamaki, Antti H.; Kakko, Tia; Kemell, Marianna L.; Wiedmer, Susanne K.; Heikkinen, Sami; Kilpeläinen, Ilkka; King, Alistair W. T. (2017)
    Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water-free topochemical modification of the nanocellulose (a process denoted as "WtF-Nano"). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co-solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non-dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide-angle X-ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1D and 2D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters.