[dipl] Kemian tekniikan korkeakoulu / CHEM

Permanent URI for this collection

Browse

Recent Submissions

Now showing 1 - 20 of 1987
  • Item
    Evaluating the fabrication and performance of sulfonated biochar composite membranes for copper redox flow battery
    (2024-03-12) Syväniemi, Sakari; Badenhorst, Wouter; Kemian tekniikan korkeakoulu; Murtomäki, Lasse
    The combined doubling of global energy requirements and pressure of climate emergency requires the large scale adoption and integration of energy storage with renewable energy sources. Redox flow batteries (RFBs) are increasingly considered a key technology in enabling the energy transition due to its scalability, competitive long-term cost, and installation flexibility. Furthermore, recent developments in alternative RFB chemistries, such as with the hybrid all-copper system, have allowed for further sustainable opportunities in electrolyte sourcing, and materials development. However, both the significant cost of high performance membranes and the EU's planned restriction of per-polyfluoroalkyl substances including Nafion membranes currently hinder RFB adoption. Thus, biochar, was investigated as a sustainable membrane additive for application in copper redox flow battery (CuRFB). Derived from D(-)-fructose by pyrolysis, biochar samples were sulfonated for a range of hours before addition to sulfonated poly (ether ether ketone) (SPEEK) casting solutions and drop cast on SF601 porous separators. The resulting sBiochar composite membranes were characterised by IR, IEC, TEM, SEM and EIS. All sBiochar membranes showed increased current efficiency during 25 mAcm-2 single cell cycling by approximately 5 and 10% from sPEEK and SF601 respectively. Furthermore, selected sBiochar membranes showed an average increase in maximum discharge power by 8\% and significant improvements in self-discharge time and capacity decay. It is suggested that these increases are due to the high ion conducting surface area and additional hindrance of copper species by sulfate groups provided by the sbiochar. Considering these improvements the novel sBiochar membranes fabricated in this work are proposed as a viable inexpensive candidate for electrochemical reactors requiring high selectivity and superior ion exchange capacity.
  • Item
    Viral block co-capsid coating for DNA origami
    (2024-03-12) Enlund, Eeva; Seitz, Iris; Kemian tekniikan korkeakoulu; Kostiainen, Mauri
    Viral capsid proteins have the unique ability to self-assemble into various shapes, most commonly adapting icosahedral or helical capsid symmetries. The capsid assembly is regulated by the environmental pH, ionic strength, and size of the viral genome. Cowpea chlorotic mottle virus (CCMV) can adapt various morphologies based on environmental conditions. Additional-ly, its capsid proteins can be directed to assemble into well-defined shapes using DNA origami as a template. The aim of this thesis is to create a block-like capsid coating for DNA ori-gami using two capsid protein types. This requires site-specific control of the growth of tube-like CCMV capsid protein assemblies, utilizing 6HB DNA origami as an assembly platform. To this end, the electrostatic interactions between the capsid proteins and the DNA origami were eliminated. Site-specific nucleation along the structures was achieved by complementary base pairing between DNA-functionalised proteins and DNA origami struc-tures equipped with single-stranded DNA overhangs. Further growth was enabled by the addition of plain capsid proteins. The success functionalising the capsid protein with single-stranded DNA was evaluated using SDS-PAGE and mass spectrometry. The 6HB coating was analysed using agarose gel electrophoresis and transmission electron microscopy. The results suggest that the functionalised proteins bind to the origami structure. However, due to the low yield of the functionalised pro-teins, most nucleation sites remained unoccupied. In addition, it cannot be conclusively stated if a capsid coating is growing from the nucleation site. The coating could be aided with the use of positively charged native CCMV capsid proteins. If successful, co-capsid coating for DNA origami could have potential for many biomedical applications such as vaccines or drug delivery systems.
  • Item
    Valorization of Fermentable Sugars from Hemicellulose Side Stream
    (2024-03-12) Hämäläinen, Petteri; Taskila, Sanna; Ojamo, Heikki; Kemian tekniikan korkeakoulu; Oinas, Pekka
    Forest industry generates large amounts of hemicellulose-rich side streams every year. These carbon-rich side streams can be valorized for fermentation processes, providing sustainable source of fermentable sugars. This thesis studied microcrystalline cellulose (MCC) production side stream and its suita-bility for fermentation as a carbon source for range of micro-organisms. The side stream was analysed for composition of sugars and inhibitors. MCC hydrolysate contained range of monosaccharides and inhibiting compounds, with xylose being the most dominant sugar and furfural the most dominant inhibitor. Liquid side stream was evaporated for higher sugar content before valorizing it for fermentation. Four micro-organisms were selected for this study by their relevance in literature and the main product it could produce in industrial scale. Two lactic acid producing bacteria Microbe A and Microbe C, polyhydroxyalkanoates (PHA) producing bacterium Microbe B and mycopro-tein producing filamentous fungus Microbe D were cultivated in the hydroly-sate. Cultivations were conducted in two different total sugar concentrations of hydrolysate, 70 g/l and 140 g/l in shake flask scale. Growth of bacteria in hydrolysate cultivations were measured with optical density (OD) readings and fungus by consumption of sugars during the cultivation. By the results of growth curves fitted with DMfit software, Microbe A had most significant growth in higher concentrated hydrolysate with highest OD value (2.25) and maximum growth rate (0.17 h-1). Microbe B and Microbe C had only minor growth in higher concentrated hydrolysate and Microbe D showed no growth in the media. The results showed that the untreated side stream was a potential source of carbon for Microbe A but not suitable for Microbe D cultivation. However, fur-ther research and optimization is required for able to utilize the hydrolysate in bigger scale fermentations and to get more knowledge on why other microbes did not grow in the hydrolysate as well.
  • Item
    Utilization of the Ty 1 VLP for the compartmentalization of enzymatic reactions in Saccharomyces cerevisiae
    (2024-03-12) Leppänen, Heidi; Kamravamanesh, Donya; Kemian tekniikan korkeakoulu; Frey, Alexander
    Enzyme compartmentalization is an intriguing topic of research where the enhancement of the functionality of a given enzyme is pursued by enclosing the enzyme inside a protein-based compartment. Virus-like particles (VLP) are one type of such compartments and among them is the Ty1 VLP found in the yeast Saccharomyces cerevisiae. It has been previously shown that the green fluorescent protein (GFP) can be fused with p2, the main capsid protein of the Ty1 VLP. Here, this fusion procedure is tested for enzymes, namely phosphoribosylanthranilate isomerase (TRP1) and α-ketoisovalerate decarboxylase (KIVD), both expressed under the galactose-inducible GAL1 promoter. The enzymes were fused with p2 following standard laboratory procedures used in the field of biotechnology. The presence of both the free enzymes and the enzyme-VLP fusions was verified with cell fractionation, SDS-PAGE and Western blotting. For TRP1 and TRP1-P2, spotting assays were also used to study the activity of the enzymes. Additionally, the utilization of KIVD in the production of the higher alcohol 2-phenylethanol (2-PE) was tested, and the production levels achieved both with free KIVD and the KIVD-P2 fusion construct were measured with gas chromatography. For both enzymes, the fusion with the p2 capsid protein was successful. In the case of TRP1, the spotting assay showed that the GAL1 promoter had been induced also in the presence of glucose, and the cells containing the enzyme were able to grow on glucose-containing medium. However, the cells did not grow on galactose, and the reason for the phenomenon could not be solved. The 2-PE production levels were slightly higher with free KIVD compared to KIVD-P2 but there was some uncertainty to this result. Very little research has been previously conducted on the utilization of the Ty1 VLP in the heterologous production of interesting compounds, so there is novelty to this work. Further studies are needed to establish the role of the Ty1 VLP in metabolic engineering.
  • Item
    Catalytic upgrading of hydrothermal liquefaction biocrude
    (2024-03-12) Huomo, Kaarlo; Rautiainen, Sari; Lehtonen, Juha; Kemian tekniikan korkeakoulu; Alopaeus, Ville
    The aim of the thesis was to improve the quality of pine biocrude oil by hydrothermal deoxygenation (HDO). The experiments adopted an approach to evaluate the effects of pre-treatment, catalysts, and HDO conditions on crude oil quality. The pre-treatment and HDO together reduced the oxygen content from the original 29.8% to 21.5%-26%. The reduction in oxygen content was accompanied by an increase in higher heating value (HHV), which averaged 31.21 MJ/kg. In the catalyst comparison experiments, the unsulfided Ru/AC, the sulfided Ru/AC, and the sulfided Ni/Mo catalyst performed similarly in terms of crude oil elemental composition. In a comparative test of the catalysts, an average deoxygenation (DOD) of 5.83 % was recorded. The catalysts had very similar impact to the results in terms of elemental composition. Improvements in the optimization of the three variables, temperature, pressure, and time, were not effective and did not show a combination that favored both deoxygenation and high biocrude yield. However, temperature was found to be the most important determinant in the experiments in terms of yield as lower temperature yielded more biocrude. In the optimization of crude oil yields, 320 °C, 5 bar pressure and 4 h reaction time gave the highest yields of 54.4 % and 55.85 % for both mass and carbon balances. The conditions that gave the highest HHV were observed when the reaction took place at 380 °C, 5 bar and over 2 h, giving an HHV of 32.6 MJ/kg and thus the highest oxygen removal. Overall, the difference in HHV and deoxygenation between tests was quite minimal. In catalytic processing, the interaction of the different catalysts is crucial. The work highlights the importance of the balance between temperature, pressure and reaction time, and results in an improved HDO-process to enhance biocrude yield and quality.
  • Item
    Reduction of xylose with molecular hydrogen for xylitol production in Rhodococcus opacus
    (2024-03-12) Kääriäinen, Katri; Nyyssölä, Antti; Jämsä, Tytti; Kemian tekniikan korkeakoulu; Scheller, Silvan
    In a search for environmentally friendly industrial production, biocatalysis can offer an alternative to chemical catalysis. Processes based in biocatalysis often benefit from milder reaction conditions decreasing the energy demand of the process and the inherent biodegradability of natural catalysts. However, many of these natural catalysts are cofactor dependent enzymes and require cofactor recycling. This cofactor recycling typically generates an additional co-product complicating the purification of the target product. One way to avoid this is to use hydrogenases. These enzymes can recycle the cofactor without the formation of troublesome co-products. The aim of this thesis was to construct a whole-cell biocatalytic xylitol production platform with cofactor recycling powered by hydrogen. To achieve this a strain of a hydrogen-oxidizing bacteria capable of heterologous expression of xylose reductase (XR) was constructed. Three XR genes were transformed into a hydrogen-oxidizing bacterium Rhodococcus opacus MR11 expressing its native soluble hydrogenase. One of the transformants showed sufficient XR activity. Xylose was converted to xylitol successfully in resting cells of this strain. However, based on these tests the cofactor recycling was inefficient using hydrogen likely due to differing cofactor preferences of the XR and hydrogenase.
  • Item
    Implementation of hydrogen transmission pipeline design
    (2024-03-11) Lappalainen, Teemu; Härö, Erkki; Kaarlela, Markus; Kemian tekniikan korkeakoulu; Järvinen, Mika
    Hydrogen sourced from renewable energy sources is seen as a significant pathway for the European union to reach its net zero carbon emissions goals in the coming decades. Renewable hydrogen production could enable higher utilization of intermittent renewable energy and indirectly electrify difficult to electrify sectors such as long-distance freight, steel production and fertilizer production with Power-to-X pathways. To facilitate these plans, significant investments into infrastructure to produce, store and transport hydrogen are required. Billions of euros worth of investments for pipeline infrastructure alone are estimated to be required to meet Europe’s goals. While thousands of kilometres of hydrogen pipelines already exist in Europe and around the world, the standardization and existing instructive materials are behind those of natural gas pipelines, which have been standardized and regulated for years. Hydrogen imposes distinct design considerations due to its tendency to leak from vessels housing it and to embrittle metals. In this thesis, a literature review of recent studies, standards and guidelines related to the design of hydrogen transmission pipelines is conducted. Additionally, semi-structured thematic interviews on the subject are held with a set of experienced engineers. The thesis identifies important design considerations for hydrogen transmission pipelines along with relevant gaps in standardization and design conventions. The knowledge gained from this research is collected into a guideline on the design of hydrogen transmissions pipelines. The guideline is meant to give engineers who are not familiar with the subject a general overview on the unique considerations relating to transmission pipelines housing and transporting hydrogen.
  • Item
    Dyeability study of hemicellulose-rich man-made cellulosic fibers
    (2024-03-12) Sharma, Ritesh; Hummel, Michael; Roselli, Annariikka; Kemian tekniikan korkeakoulu; Tehrani, Ali
    This thesis aimed to study the dyeability of hemicellulose-rich man-made cellulosic fibers, along with viscose, lyocell, and cotton, using two reactive dyes (C.I. RR141 and C.I.RY6). Before conducting the dyeability tests, preliminary experiments were carried out for the hemicellulose-rich fibers to understand the leaching behavior of hemicellulose from the fibers through alkali treatment. Sodium hydroxide (NaOH) at 5 and 10 g/L and sodium carbonate (Na2CO3) at 5, 10, and 20 g/L were tested. Various characterization processes conducted at this stage revealed the removal of hemicellulose content from the fiber when using a NaOH concentration of 10 g/L. However, the hemicellulose removal from the fiber was minimal, while 5 to 20 g/L Na2CO3 was used as an alkali agent. Having established that the hemicellulose content was stable when using Na2CO3 concentrations between 10 to 20 g/L, dyeability tests were carried out using 5 and 10 g/L NaOH concentrations and 15 g/L Na2CO3 concentrations. The results obtained showed that dyeing performance for the man-made cellulosic fibers is better compared to cotton across all alkali concentrations, with the highest color strength (K/S) values for hemicellulose-rich fibers for both dyes. Furthermore, the results obtained from the color change to washing, rubbing, and light fastness tests revealed that there is a minimal effect of different alkali concentrations on fastness properties, as all the fabrics showed very good to excellent color fastness results.
  • Item
    The costs of single-use consumer packaging
    (2024-01-23) Hart, Janika; Lahtinen, Jussi; Kemian tekniikan korkeakoulu; Paltakari, Jouni
    The price of a fast-moving consumer good (FMCG) includes the costs of its packaging which are made up of multiple different costs throughout the packaging supply chain and life cycle, from production to use to disposal. Some of these costs are initially covered by fees to companies with producer responsibility, but most packaging related costs are paid for by consumers when they buy a packaged product, when they pay residential waste fees and through taxes. Since these costs are spread throughout the supply chain, the total amount of packaging related costs per product are not well known, especially by consumers. The literature review explains the background to single use, legislation related to packaging and packaging waste, producer responsibility and municipal waste management of packaging. To gain further knowledge and understanding on the costs of single-use packaging in Finland and make these costs more visible to consumers, relevant stakeholders in the packaging supply chain were interviewed. These included brand owners, waste management organisations and other relevant organisations. The interviews were held as in-depth interviews, where interviewees were asked about topics that were predetermined to be possible factors to packaging related costs of the organisation types. The interviews aimed to explore the causes, development, and future trends of these costs, as well as their impact on the organisations and costs to consumers. Additionally, information related to costs was gathered from literature and cost calculations were done to estimate packaging related costs of packaging case examples and residential waste fees around Finland. Based on the stakeholder interviews, it was concluded that in recent years, there has been a substantial increase in packaging related costs, such as producer responsibility fees and costs of waste management. These costs will continue to increase, as legislation is updated, and more requirements are added. The recent changes in EU legislation that have brought costs to brand owners and waste management, are increasingly complex reporting requirements of packaging put on the market and higher recycling targets causing additional costs due to the need to expand the separate collection of packaging. As the EU is aiming for a transition to a circular economy, and the single use system and its costs are changing, it could be considered, if in some situations reuse can be a cheaper alternative to single use.
  • Item
    Synthesis and characterizations of chromium doped Fe3Se4: Magnetic and electronic transport properties
    (2024-01-23) Pham, Trang; Tewari, Girish; Kemian tekniikan korkeakoulu; Karppinen, Maarit
    This study investigates chromium(Cr)-doped Fe₃Se₄, revealing complex interactions between crystal structure modification and magnetic/electronic behaviors. The solid-state synthesis of Fe₃Se₄ confirms its monoclinic structure (I2/m). Cr doping induces significant shifts in XRD patterns, indicating alterations to the lattice structure and effective Cr integration in the chemical formula (Fe1-xCrx)3Se4. The coexistence of monoclinic phases I2/m and C2/m indicates polymorphism, offering insights into structural changes during Cr doping. Magnetic property analysis shows the ferrimagnetic behavior of undoped Fe₃Se₄ with a Curie temperature of 325 K. Cr doping results in diverse magnetic responses, including reductions of Curie temperature at x = 0.1 and transformations to hard magnetic properties. The x = 0.1 doping level emerges as a promising candidate for tuning magnetic properties. Resistivity analysis explores electronic transport, highlighting temperature-dependent variations in Cr-doped samples compared to the undoped Fe3Se4 sample. The intricate influence of Cr doping on electronic properties, linked to crystal structure anisotropy modifications, is also clarified in this study.
  • Item
    Strep-tag based method for protein quantification
    (2024-01-23) Kotovuori, Tomi; Malkamäki, Maaria; Kemian tekniikan korkeakoulu; Linder, Markus
    Protein quantification is the base for protein analysis. As understanding of proteins is essential in numerous different fields, they are heavily studied. There are a lot of different quantification methods that either analyse the total protein or a specific protein content of a sample. However, no method is suitable for all types of protein samples, as each assay has their own requirements, advantages and challenges. This thesis focuses on the quantification of a specific protein using a peptide tag called Strep-tag. This new form of protein quantification is based on a western blot assay coupled with radioactive detection and it has been tested with silk-like proteins. The silk-like recombinant proteins containing a Strep-tag in their N-terminus were expressed in Escherichia coli. They were purified using affinity chromatography and quantified using Strep-Tactin, a ligand, which binds specifically and with high affinity to a Strep-tag present in studied proteins. Strep-Tactin has been modified to contain a radioactive tritium label, the decay of which is measured at the final stage of the assay using liquid scintillation counting. The radioactivity measured is proportional to the protein concentration of the sample. The aim of this thesis was to improve and optimize this method, as it was relatively new. In addition to making sure the protocol steps worked as intended, protein detection limits were determined and different forms of Strep-tags and Strep-Tactins were compared to find the superior combination. This quantification method has shown great potential by producing results with high accuracy faster than other common methods in the field.
  • Item
    Solid-state batteries for electromobility applications – Towards market integration by 2030, through Horizon Europe funding program.
    (2024-01-23) Hendrickx, Pierre; Michel, Camille; Kemian tekniikan korkeakoulu; Karttunen, Antti
    In the context of decarbonisation of Europe by 2050, solutions need to be developed to accommodate our society to less dependency on fossil fuels energy, especially in the transportation sector. Innovative batteries have been at the core of research for electromobility applications. This thesis considers the most advanced ones at this stage: Solid-state batteries. Several materials for anode, cathode and electrolyte have been reviewed and strategic choices have been made to build a project answering an example of Horizon Europe call, namely “Advanced materials and cells development enabling large-scale production of Gen4 solid-state batteries for mobility applications”. Additional expertise needed to answer this call have been highlighted and strategies towards maximising such a project’s impacts (through exploitation and communication strategies) have been drafted. Overall, this thesis provides a comprehensive path to commercialisation for solid-state batteries in the transportation sector, through European fundings.
  • Item
    Numerical simulation of fire resistance tests of stone wool under different fire scenarios
    (2024-01-23) Coudé du foresto, Victoria; Troudet, Estelle; Kemian tekniikan korkeakoulu; Hostikka, Simo
    Fire safety engineering is a critical aspect of building design, particularly as traditional approaches based on standardized conditions may not fully capture the dynamic nature of real-world fire scenarios. This research focuses on the impact of temperature-dependent material properties, specifically thermal conductivity, on fire conditions modelling, with an emphasis on rock wool panels used for HVAC duct protection. The study aims to enhance the accuracy of fire resistance assessments by incorporating temperature sensitivity into models and optimizing rock wool panel thickness under standardized fire conditions. Hypotheses suggest that considering temperature-dependent properties will reveal significant differences in thermal behaviours, and optimizing panel thickness can provide insights into performance-based design. The study introduces a simplified numerical model and emphasizes the importance of diverse fire scenarios in designing fire protection systems. While economic advantages can be gained through parameter adjustments, the study calls for more sophisticated models to further enhance results and explores a range of optimization possibilities for fire protection systems.
  • Item
    Industrial-scale microwave heating of waste oils and fats – Technology evaluation
    (2024-01-23) Kostiander, Niilo; Hommes, Arne; Turkka, Jyri; Kemian tekniikan korkeakoulu; Oinas, Pekka
    Research of renewable energy technologies has gained increasing amount of interest in recent years. Microwave (MW) heating has been found to have benefits in a wide range of fields and it has successfully replaced conventional heating methods in many applications, such as food, polymer and ceramics processing. With the technology, notable reductions in processing time, fouling and greenhouse gas emissions have been achieved. However, widespread use of microwaves in industrial scale has not yet taken place. The aim of this thesis is to provide a general view on the feasibility of microwave technology in heating waste oils and fats in hydrotreated vegetable oil (HVO) pre-treatment process. Waste lipid feedstocks tend to form solid particles on the walls of conventional heat exchangers in high temperatures. MW heating, with its unique heating mechanism, could possibly address this problem by eliminating the hot surfaces of the equipment and hence reduce fouling. This would cause less downtime of the plant increasing the annual production capacity. The general advantages of MW heating are rapid heating with minimal heat gradient and possible enhanced reaction rates. The disadvantages are difficult scale-up and possible increased side-reactions. In the literature study, it is concluded that oils and fats can be effectively heated because of their low specific heat capacity and high penetration depth of microwave irradiation. Moreover, some promising laboratory results have been published about MW processing of lipids; the irradiation has been found to enhance bleaching and degumming of oils. In the applied part, the technical feasibility and costs of microwave heating are assessed, using an example design case from the HVO pre-treatment process. In the example case, a process stream of 160 t/h is heated from 160 ℃ to 280 ℃ with MW irradiation. Based on the results, it is challenging to feasibly apply microwave heating in industrial-scale heating of waste oils and fats. The limited capacity of a single microwave heater increases the required number of modules (16), resulting in high investment costs (65 M€) and large physical area (837 m2) needed. The annual energy costs are estimated to be 20 M€. The high operating costs (26 M€) are caused by the low energy efficiency of microwave heaters (55%) as well as relatively high maintenance costs (6 M€/a) due to the yearly requirement to replace the MW generators. The main challenges of MW heaters are low energy efficiency and flow capacity. Microwave heating needs to significantly reduce fouling or offer some other benefit in HVO pre-treatment performance to compensate for the disadvantages. Further development of scaling up the technology is needed and more studies on heating waste oils and fats with microwaves should be conducted.
  • Item
    Utilization of future food court side streams as alternative carbon and nutrient source for plant cell cultures
    (2024-01-22) Lillberg, Amanda; Ritala, Anneli; Pajumo, Maria; Kemian tekniikan korkeakoulu; Jouhten, Paula
    Current food production capacity with only conventional agriculture is not sufficient to solely sustain the food demand for increasing human population. Sufficient food production could be enabled by combining conventional farming with cellular agriculture. Cellular agriculture refers to the production of agricultural commodities with plant, microbial and animal cells. Cellular agriculture, such as single cell protein synthesis, could also reduce the food production associated burden to land use and climate of food in the future. However, applications in cellular agriculture comes with many challenges, one of which includes the high costs for growth medium components. The aim of this thesis was to utilize alternative sources for carbon and nutrients for the plant cell growth medium to reduce costs. The alternative sources assessed in this thesis included biodegradable side streams from shopping centre environment. There, side streams accumulate from food courts and markets and could include orange peels, soda drink waste mix, expired bread, spent coffee grounds and brewer’s spent grains. Urine was also considered as a potential nutrient source since it possesses many valuable compounds that are required for the growth of plant cells. Future efficient purification technologies could permit the food regulation to allow the use of urine as a nutrient source. Plant cells require carbon and nutrients in a soluble form, therefore pre-treatments were applied for solid side streams to release monosaccharides from longer polysaccharide chains. The utilization potential of the side streams was evaluated by using them as culture medium components for cultivations of three non-taxonomically related plant cell lines: arctic bramble, tobacco BY-2, and barley. The side stream suitability was assessed by using biomass production after a cultivation period as a scale for comparison. Soda drink waste mix and synthetic urine contributed for the highest biomass concentrations, which was used as a measure for growth. These side streams were used as main components for optimization of growth media composition. Both side streams were successfully utilized for cultivations, especially for arctic bramble with notable increase in biomass concentration. Side streams were found to be potential culture medium components for plant cell cultures but notable differences in growth and growth behaviour between the studied plant cell lines were observed. The appliance of thus far unutilized side steams would enhance the circular economy and improve the food value chain. In addition, the economical sustainability of production would improve as costly components would be replaced with unutilized sources.
  • Item
    Reactivity in organic precursors in atomic/molecular layer deposition
    (2024-01-23) Partanen, Olga; Jussila, Topias; Kemian tekniikan korkeakoulu; Karppinen, Maarit
    The modern era constantly requires thinner and more complex materials. A combined atomic and molecular layer deposition (ALD/MLD) is a versatile technique for depositing extremely thin but functional films. ALD/MLD has attracted interest due to the possibility to deposit high-quality inorganic-organic hybrid thin films with mixed properties from both inorganic and organic parts of the thin film. The organic parts of the ALD/MLD hybrid thin films can enhance a great number of properties such as flexibility and electric effects. Although most of the research focuses on developing novel ALD/MLD processes and characterizing the material properties, it is needed to consider how the reactivity of precursor compounds affect the growth and stability of the thin film. In this thesis, reactivity of organic materials is reviewed to investigate which makes organic compound reactive and how does reactivity affect the stability of the thin film. In this thesis, five inorganic-organic hybrid materials were fabricated by ALD/MLD. Four of them were completely novel: Co-BDT, Co-HQ, Fe-ADN, and Fe-ADH. For broader study about the reactivity and stability of different organic compounds, also Co-TPA thin films were deposited. The processes were developed, and the thin films were characterized with various characterizing methods. Lastly, the reactivity and stability of thin films were analysed on the perspective of the film growth and aging stability. The Co-based materials deposited in this thesis yielded high-quality hybrid thin films. Fabrication of the Fe-based materials turned out to be more challenging: Neither of the Fe-based materials showed saturation, and precursors might not have reacted fully. However, Fe-ADH showed interestingly crystalline structure which attracts further interest on the material. Additionally, further research and development of novel ALD/MLD hybrid thin films is needed for better understanding of reactivity and its effects on thin films.
  • Item
    Co-precipitation of Ni0.8Mn0.1Co0.1(OH)2 with a draft tube reactor
    (2024-01-23) Lepistö, Riikka; Aromaa, Jari; Koponen, Markus; Kemian tekniikan korkeakoulu; Lundström, Mari
    As the world moves towards cleaner and more sustainable energy solutions, the demand for lithium-ion batteries (LiBs) has surged due to their conclusive role in powering of electric vehicles (EVs), renewable energy systems, and portable electronic devices. Cathode active materials (CAMs) are the key components of LiBs since they have a vital effect on the overall performance of the battery. Different types of CAMs exhibit varying properties, such as energy density, power output, and lifespan. Preparation of CAM typically involves the synthesis of their precursors (pCAMs) via co-precipitation, followed by calcination with lithium salts. Producing of appropriate precursors is crucial as it influences the electrochemical performance of the resulting CAM. However, obtaining battery-grade pCAM is known to be challenging due to the sensitivity of the precipitation process and due to the several key characteristics of the product, such as particle mean size, morphology, and density, thus, more research on pCAM synthesis was needed. In this study, the most common CAMs were investigated to find out the most desirable state-of-the-art cathode chemistry for its pCAM synthesis. Nickel-rich precursor of LiNiMnCoO2 (NMC811) was chosen as the target chemistry due to its high energy density, good cyclability, and low cobalt content. Furthermore, the battery graded NMC811 precursor characteristics were explained as well as how the operational factors influence on the product quality. Factors affecting fluid motion, such as stirring speed, impeller type and reactor configuration, are one of the operating parameters that have an impact on particle size, shape and density of the pCAM product. As a part of Metso’s Precursor Development project, a draft tube circulator mounted inside a laboratory scale reactor was examined to see if it was possible to obtain battery grade pCAM. Draft tubes are known to improve fluid motion and hence the dispersion of the particles. The study showed that it can be possible to produce NMC811 precursors with good quality. In addition, four different impeller systems were studied among with different mixing velocities. Single axial impeller system at high stirring speed resulted in dense and spherical pCAM product with relatively low agitation duty.
  • Item
    Validation of an assay for protein quantification using tritium detection
    (2024-01-22) Niskanen, Linnea; Malkamäki, Maaria; Gandier, Julie-Anne; Kemian tekniikan korkeakoulu; Linder, Markus
    Validation of a new analytical method is done to estimate its fit for purpose prior taking the method as part of routine analyses of the laboratory. In method validation series of predefined experiments are done to determine values for chosen validation characteristics. With statistical tests it is possible to identify the parts of the assay that affect to the reliability of the assay. Different regulatory bodies give varying recommendations for validation procedure and different definitions of terminology may lead to misinterpretations and wrong conclusions. The aim of this work was to improve and validate a novelty protein quantification method, that is based on detecting tritium labelled ligand, StrepTactin-XT from protein sample. StrepTactin-XT binds specifically to Twin-Strep-tag. In this assay the Twin-Strep-tag is coded into N-terminal of the protein of interest, silk protein CBM-AQ12-CBM. The aim was to validate the methods suitability for its intended purpose and to determine linearity of calibration curve, limit of detection (LOD), limit of quantification (LOQ), accuracy and precision. The validation procedure was planned following recommendations of accredited validation organizations, but also taking into account the limitations that were set by the properties of the assay. The linear range of the assay was analysed using Fisher variance ratio and it was set to cover 6-350 ng. LOD and LOQ were determined using signal-to-noise relationship, and they were set to 6 ng and 13 ng, respectively. Relative error had variance between 0,3-70 %, making the average accuracy to be 78 %. For precision, the repeatability was on average 95 %, but due to limited time there was no possibility to measure intermediate precision.
  • Item
    Comparative analysis of dyeing behaviour of cellulose and regenerated cellulose in solvent-assisted salt-free reactive dyeing
    (2024-01-23) Dutta, Shubhajit; Periyasamy, Aravin Prince; Kemian tekniikan korkeakoulu; Tehrani, Ali
    This research aimed to investigate the viability of a solvent-assisted salt-free reactive dyeing method for cellulose & and regenerated cellulose using reactive dyes without adding salt and employing solvents, such as EtOH, IPA, and PrOH as alternatives to conventional dyeing. Eight different reactive dyes with distinct reactive groups were involved in this study. The study focused on assessing the color strength, dye exhaustion, fixation, and colorfastness properties of cotton and viscose fibers and how and why they change their dyeing behavior in different reactive dyes in several solvents. It was found that reactive dyes were less soluble in alcohol due to the polarity of the solvents and sulfonate groups in their chemical structure than in water. Moreover, the porosity and the crystallinity of the fibers have been investigated to understand the dyeing characteristics of the fibers. On average, the K/S values of viscose fabrics dyed with the conventional dyeing method were approximately three times higher than those values on cotton fabrics due to having a more porous and less crystalline area than cotton. In contrast, due to the reactive dye hydrolysis in alcohols being expected to be less than that in water, reactive dyes could not make enough covalent bonds with cotton or viscose fiber as in water. The exhaustion of reactive dyes on cotton had overall higher exhaustion%, and fixation% in alcohol than viscose compared to conventional dyeing. Contrarily, viscose fibers, as being man-made and chemically processed, exhibited lower exhaustion%, and fixation% in comparison. Furthermore, substituting water with solvents did not compromise the fabric's wash, rub, and light-fastness properties, which remained the same. It can be concluded that solvent-assisted salt-free dyeing performed better in comparison to conventional dyeing for cotton with reactive dyes rather than viscose.
  • Item
    Set-up and incorporation of a nucleic acid purification protocol in a PCR based diagnostic test for respiratory pathogens
    (2024-01-23) Boström, Sanna; Hokynar, Kati; Piilola (Piitulainen), Hanna; Kemian tekniikan korkeakoulu; Linder, Markus
    Respiratory tract infections are prevalent worldwide, and their mortality rates are generally low in individuals with good health. However, such infections can be severe and sometimes fatal, especially among young children, the elderly, and immunocompromised people. Especially with severe infections fast and reliable diagnosis is crucial. Traditional diagnostic methods for respiratory pathogens, e.g., culturing, are time-consuming and laborious. Molecular diagnostic methods, such as nucleic acid amplification-based tests have revolutionized the diagnostics of respiratory tract infections and are now the golden standard method. The aim of this thesis is to develop and optimize a nucleic acid extraction protocol for a prototype diagnostic test on Novodiag® system detecting respiratory pathogens and to evaluate the efficacy of the developed extraction method. Novodiag® is a rapid molecular diagnostic test for detecting infectious agents and antibiotic resistance developed by Mobidiag. The study started by examination of extraction efficacy of different silica types with both DNA and RNA targets. Next phase included optimization of the binding buffer. Finally, the sample preparation method was integrated into Novodiag® cartridge and its performance was studied by comparing automated Novodiag® extractions to manual version and to a reference method. This thesis led to the discovery of a novel alternative silica that not only matched the performance of the standard silica but also surpassed it when targeting RNA. Optimization of the binding buffer for RNA targets was successful, and the sensitivity increased up to 100-fold compared to the original binding buffer. However, the new optimized binding buffer did not reach the sensitivity of the reference method but was decreased 10-fold compared to easyMAG®. The integration of sample preparation method to the Novodiag® was successful, but evaluation of extraction efficacy showed approximately a 10-fold decrease in sensitivity compared to manual nucleic acid extraction. Based on the results of this thesis, silica examination should be further studied, especially with both DNA and RNA targets and also in the presence of clinical sample matrix. In addition, sample preparation protocol in Novodiag® should be further optimized to reach the same or better performance and sensitivity as in manual nucleic acid extraction.