One of Bio4Energy’s greatest assets is its students. This month, no less than five of them are either defending their PhD thesis or giving their licentiate lecture or mid-term PhD seminar. In this case, five seminars make for five lines of excellent research on:
- Development of carbon foams for use as electrodes or sorbents in water purification;
- Heterogeneous catalysis applied to a pulping by-product for the purpose of making bio-based polymers or biofuel compounds;
- Spectroscopic characterisation of lignocellulosic biomass;
- Lengthening of tree fibres by using nanofibres and nanocrystals, and;
- Characterisation of biomass mixed with waste and compound emissions.
Flexible carbon foams – Article published in the Scientific Reports’ series of the Nature Publishing Group
The study led by Bio4Energy researchers shows that the flexibility of carbon foams made from bio-based materials may be further increased by applying direct carbonisation to melamine foams. Melamine is a crystalline, slightly water-soluble solid, used chiefly in organic synthesis and in the manufacture of resins, especially melamine resins.
Thus, the researchers write in an article recently published in Scientific Reports, due to their light weight, high porosity, hydrophobicity and high adsorption capacity, such foams could find several applications as electrodes or sorbent materials in water purification;
"In this paper, we show that after the [high-temperature treatment by means of] pyrolysis and activation process, the carbon foam retains the open pore network of the precursor foam and remains mechanically flexible, and, furthermore, with a proper selection of suitable synthesis conditions, foams possessing a different hydrophobic/hydrophilic nature may be obtained".
The article, Industrially benign super-compressible piezoresistive carbon foams with predefined wetting properties: from environmental to electrical applications, was published 6 November 2014 in Scientific Reports' series by the well-respected Nature Publishing Group. Subsequently, Bio4Energy PhD student Tung Ngoc Pham held an open seminar to explain the work, 3 December at Umeå University in Sweden.
The following article authors are acknowledged: Tung Ngoc Pham, Ajaikumar Samikannu, Jarmo Kukkola, Anne-Riikka Rautio, Olli Pitkänen, Aron Dombovari, Gabriela Simone Lorite, Teemu Sipola, Geza Toth, Melinda Mohl, Jyri-Pekka Mikkola and Krisztián Kordás.
Turning monoterpenes into value-added 'green' chemicals, using heterogeneous catalysis
Mikhail Golets PhD thesis, Heterogeneously Catalysed Valorisation of Monoterpenes to High Value-Added Chemicals
Edited abstract: In the Nordic countries pulping industry turpentine is widely available as a tonnage by-product. Despite its interesting properties and promising application possibilities this fraction is commonly burned in the recovery boilers for energy. Although the chemical composition of turpentine depends strongly on the specific pulping process, α-pinene is the predominant compound and as such the most studied. The general message of this thesis is the successful implementation of the heterogeneous catalysts in one-pot value-added upgrading of crude turpentine and specific terpenes, particularly α-pinene.
Concepts allowing the production of fragrances, resins, plastics and pharmaceutical compounds are presented in the current study. Both commercial (Amberlyst 70) and self-prepared (Me/Al-SBA-15 or TiO 2) catalysts were studied in several reactions including acetoxylation, isomerisation, dehydroisomerisation and oxidation. Both commercially purified α-pinene and crude thermo-mechanical turpentine were used as input materials in the catalytic one-pot synthesis of value-added compounds.
Spectroscopic characterisation of lignocellulosic biomass
Mikael Thyrel PhD thesis, Spectroscopic Characterisation of Lignocellulosic Biomass
Edited abstract: This work focused on the characterisation of organic components and inorganic elements in lignocellulosic biomass. The chosen biomass models were mostly wood from conifers and straw from rhizomatous grasses but also forest-based residues and plants from agriculture. X-ray fluorescence (XRF) and near infrared (NIR) spectroscopy are techniques that can potentially be incorporated in a future biorefinery concept, in which the characterisation of feedstock is crucial because of the heterogeneous nature of biomass.
XRF spectroscopy combined with principal component analysis (PCA) was used to classify a number of different biomass materials. Moreover, partial least squares regression calibration models were developed for several ash elements with good predictive capabilities. The capability of XRF and NIR spectroscopy to measure ash content in biomass was investigated and it was concluded that XRF spectroscopy was the superior method of the two, especially for measuring contaminated material.
If the two techniques were used in conjunction, it was possible to estimate the degree of contamination. In an additional study of the potential for future separation techniques, it was shown that the 2D-NIR technique is useful for classifying wood chips, as well as identifying individual wood chips with high extractive contents.
Lengthening of tree fibres by using nanofibres and nanocrystals
Saleh Hooshmand licentiate thesis, Process and Properties of Continuous Fibres Based on Cellulose Nanocrystals and Nanofibres
Edited abstract: In recent years, composites made from natural fibres based on cellulose have received increasing attention since they are thought to have a low environmental impact and good mechanical properties. However, these fibres are short and discontinuous and the conventional spinning techniques used for them result in continuous yarns with mechanical properties which are not optimal for the purpose of making high-performance bio-based composite materials. The aim of this work was to prepare continuous fibres where nano-sized cellulose crystals and cellulose nanofibres were used to improve the fibre properties. Two different strategies were used to reach this aim.
Characterisation of biomass mixed with waste and compound emissions
Mar Edo PhD seminar, Biomass Mixed with Fractionated Waste: Characterisation, Optimisation and Emissions
Edited abstract: Global population is increasing every year, implying an overall increase in the energy consumption and polluting emissions, as well as an increase in the total volume of generated household waste. In this work, a combination of biomass and household waste is being used to create a high-quality and environmentally-friendly fuel.
The project studies the production, preparation and combustion of high-quality fuels composed of biomass and municipal solid waste. Special emphasis is being put on the role of fuel composition in respect to the amount of food residue present in the waste and the type of biomass used as base. Formation and emissions of organic environmental pollutants, known as persistent organic pollutants (POPs), are also being looked at in connection to the combustion process. In addition, the characteristics and general emissions' profile of the mixed fuel/s are being studied. Two scientific articles are expected to result from this work.