Chemical Engineering

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Research Topic Summary.

The research is aimed at reducing CO2 emissions during cement production and improving the performance of new cements by replacing part of Portland cement clinker with cement additives. The aim of the work will be to synthesize additives suitable for cement, to prepare recommendations for their production technology and use. In order to obtain the greatest possible economic and environmental benefits, it is planned to use waste from other industries, local raw materials or mixtures for the synthesis of cement additives. The performance of cement with synthetic additives will be assessed according to different environmental exposure classes.

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Research Topic Summary.

Concrete is the second largest commodity after water consumed annually by the population of Earth. Due to such vast demand for the building materials, cement industry is responsible for about 5–7 % of global anthropogenic greenhouse gas emissions, with almost equal amount of CO2 emitted to the atmosphere after production of one tonne of cement. Accordingly, the scientific community is struggling to find the solution for greenhouse gas mitigation and reduction of the negative effect of the cement production. Even though, in the past decades many solutions to alleviate the adverse effect of cement production to the environment were proposed, recent studies have shown that strategies like clinker substitutions, alternative fuels and/or improved energy efficiency alone will not be sufficient enough to meet the target CO2 reductions. Thus, finding alternative cementitious materials with lower CO2 footprint than ordinary cement is one the major challenges for the building material industry and the scientific community. One of the most promising approaches is the production of low-lime calcium silicate cement (CSC). This type of binding materials not only requires lower amounts of limestone but, as well as, has lower production temperature thereby resulting in much lower CO2 emissions. Moreover, such binders are environmentally amicable not only due to lower CO2 emissions, but also for the ability to permanently store CO2 in the concrete structure in their carbonation hardening process. Implementation of such efficient carbonation technologies can potentially lead to cementitious materials becoming one of the largest global CO2 sequestration sectors. Rankinite and kilchoanite – Ca3Si2O7 – low lime calcium silicates that can be used as an alternative binder. Since the CaO/SiO2 ratio of them is almost twice as lower than ordinary cement, thus it requires lower amounts of calcareous raw materials. The fuel and energy requirements for this type of binder are also reduced since the synthesis temperature of rankinite is 200 °C lower than that of cement clinker, and kilchoanite – under hydrothermal conditions. Moreover, rankinite and kilchoanite can be produced from the same raw materials as cement clinker. Since calcium silicates can be synthesized from broad range of raw materials, it is economically conducive to use local materials. Both limestone and SiO2-containing raw materials are sufficient in Lithuania, but the suitability of the latter (Anykščiai quartz sand, granite sawing powder waste, hydro-mica clay and biofuel ash) for synthesis has not been studied. Rankinite and kilchoanite are hydraulically inactive and harden only in a CO2 environment. A highly durable microstructure of calcium carbonates and silica gel is formed. Since carbonization is determined by diffusion processes, the hardening process depends on many parameters: CO2 pressure, curing time, moisture content, peculiarities of concrete preparation, etc. It is important to examine and reconcile all of them.

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Research Topic Summary.

Short-chain fructooligosaccharides (FOS) are a group of oligosaccharides consisting of linear fructose units. In nature, they occur, at low levels, in different plant products and are of high interest as food ingredients due to their prebiotic character and organoleptic and technological properties. FOS production is performed either by the hydrolysis of polysaccharides or via enzymatic synthesis at an industrial level. Over the last decade, FOS have gained significant attention as valuable components of food and dietary supplements. Apart from implications as dietary fibers, sweeteners, and humectants, oligosaccharides are hailed for their prebiotic properties. FOS production at an industrial level is achieved either by inulin hydrolysis performed by chemical or enzymatic means. However, as the chemical methods are linked to substances that can pose a hazard to consumers' health and product safety, the enzymatic pathway is more preferred. Alternatively, direct enzymatic synthesis by the biotransformation of sucrose by fructosyl transferases and fructofuranosidases can be performed. The latter requires a deep understanding and optimization of critical parameters involved in the catalytic bioprocesses to achieve products with the desired characteristics. Currently, FOS are increasingly included in food, beverage products, and infant formulas. This rising popularity has thus accelerated the research in this field. This is also depicted by the increasing number of patents registered in the last 10 years. Food and nutraceutical industries are interested in higher FOS yields and, consequently, higher economic benefits by using innovative fermentative techniques, discovering novel microbial sources of enzymes, and optimizing the catalytic bioprocesses' critical parameters. Also, since FOS is typically incorporated into various food products and formulations, there is a great interest in the added FOS's stability during a product lifespan. Nevertheless, besides the technical aspects and challenges of FOS production, interest in the prebiotic and bioactive properties of FOS necessitates more in-depth investigations to understand better their role in healthcare. On the other hand, a synbiotic is defined as a "mixture of probiotics and prebiotics that beneficially affects the host by improving the survival and activity of beneficial microorganisms in the gut. Recently synbiotic formulations and beverages that include prebiotics like FOS and probiotic microorganisms attracted scientific attention as important tools to help maintaining good health, preventing diseases, and/or as alternatives for reducing the risk associated with diseases. This study will focus on two main aspects, the optimization of current FOS production methods and the development of synbiotic formulations utilizing oligosaccharides as a source of prebiotics. This study's objective and goals align perfectly with the current industrial demand for alternative and optimized FOS production methods. Also, they fit well with current consumer trends and interest in food products with improved nutritional and functional properties. Moreover, this study will cover the current scientific interest for further investigations on the potential health-beneficial properties these products may exert by evaluating different FOS and their fractions effects. Thus, it is highly anticipated that besides the scientific value and outputs of the planned project, successful implementation of this project's activities may lead to practical applications with the potential for commercialization. Overall, generating interest from various stakeholders and future collaborations with academic and industrial partners.

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Research Topic Summary.

The aim of this thesis is to determine the influence of treatment conditions and additives on the properties of secondary raw materials or wastes, and their use in innovative environmentally friendly technologies. Objectives: - To investigate the chemical and mineral composition, thermal stability, texture, specific surface characteristics and other physical properties of secondary raw materials. - To determine the influence of the treatment environment (saturated water vapour, CO2, etc.) and conditions (pressure, temperature, duration) on the chemical-physical properties of secondary raw materials. - To investigate the influence of additives on the chemical-physical properties of secondary raw materials. - To develop technological recommendations for the treatment and application of secondary raw materials.

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Research Topic Summary.

More and more recent scientific evidence confirms the importance of microorganisms in the human body for various aspects of health. The intestinal microflora is responsible for maintaining strong immunity and the synthesis of some vital vitamins. With the change of dietary habits, the application of new technologies of processing and production of raw materials deprives the body of natural access to the necessary nutrients, and improperly balanced diet in the human intestine can disrupt the natural microbiota, its unwanted representatives begin to dominate. Not only the role of lactic acid bacteria or bifidobacteria is important, the growth of microorganisms such as Akkermansia is inhibited by the lack of fiber and the production of high amounts of saturated fat. The aim of the study would be to develop a special-purpose model food system capable of activating the growth of specific intestinal bacterial batteries by assessing changes in the incidence of Firmicutes, Akkermansia, and Bacteroidetes. The influence of various factors on the relevant groups of microorganisms in the model systems, their interrelationships, identification of metabolism products, in vitro and in vivo studies, isolation of microorganisms, determination of species dependence by genetic methods, analysis of resistance, microbiome effects will be assessed.

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Research Topic Summary.

The current interest in biopolymers is forcing to find the ways for generation of new materials from natural polysaccharides such as cellulose, chitosan, starch, etc, and to extent the area of their applications. The aim of this project is to design and investigate new immobilization paths by using ionogenic polysaccharides as carriers of active compounds and to assess their performance under simulated conditions. The polysaccharide matrices of different charge density and amphiphilicity will be obtained by the means of chemical and mechanical modification of natural polysaccharides. Afterwards, active ingredients immobilization in biopolymer matrices methods will be determined and their interactions, the kinetics, thermodynamics of the processes will be examined. Consequently, in the frame of this project new immobilization techniques will developed with potential use in medicine, cosmetic, pharmaceutical, nutraceutical industries, etc.

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Research Topic Summary.

Hydrogen has the potential to play a significant role in tacling climate change and solving renewable energy storage problems. Water electrolysis driven by renewable electricity is considered to be the most perspective option for the development of so-called hydrogen-based economy. On the other hand, CO2 electrochemical reduction has emerged as a promising method for the conversion of CO2 and water converted into value-added chemical compounds, such as carbon monoxide, formic acid, ethylene or thanol. However, there is a need for developing better electrodes and new catalysts in order to decrease the cost of green hydrogen production or CO2 conversion into valuable chemicals. The aim of the dissertation is relevant to the development of electrochemical technologies for water electrolysis and CO2 reduction. Particular attention will be paid to the search of efficient and low-cost electrocatalysts based on nanostructured metal oxides suitable for the implementation of these processes. In order to achieve the aim, the following tasks are formulated: 1. To synthesize manostructured mixed oxide films on stainless steel; 2. To evaluate the influence of synthesis conditions on structure, composition and morphology of the prepared films; 3. To study the electrocatalytic activity of the prepared electrodes in water splitting and CO2 electroreduction.

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Research Topic Summary.

The PhD research focuses on novel nano and microstructured materials developed using aditive manufacturing technique, aiming to apply those for aerosol particle filtration. The work will aim to developing a superior material having high particle retention, good air permeability, low pressure drop and optimal mechanical properties.

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Research Topic Summary.

Large amounts of by-products and waste are produced during storage and processing of fruits, vegetables and other agro-food raw materials. Processing residues of food materials in many cases contain high amounts of valuable substances such as polyphenolics, vitamins, and saccharides; however, currently they are used rather inefficiently and, in many cases, wasted, mainly due to a lack of scientific and technological valorization of their processing methods. For instance, many berry species are known for their excellent flavour and abundance of healthy compounds possessing antioxidant and other beneficial properties. However, due to a rapid decay after harvesting, the majority of berry crops are processed into juices and other products. Pressing of juice results in large quantities of by-products, called pomace, press-cake or marc. The main task in this project will be valorization of the selected food grade agromaterials (most likely fruit and/or vegetable processing by-products and/or waste) for the production of valuable natural substances

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Research Topic Summary.

According to the priorities of the implementation of the European Green Course, the current problems of sustainability will be solved by the development and planning of use of fertilizer products suitable for organic farming. In order to obtain high-quality fertilizer products, heterogeneous multifunctional systems (functional fertilizer products) will be developed, the composition and properties of which will be evaluated, optimal compositions will be selected, technological production preconditions will be selected and recommendations for their use will be provided. It is planned to use non-traditional raw materials such as by-products of agricultural and food processing, as well as other production waste.

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Research Topic Summary.

The extensive use of synthetic plastics is a worldwide concern due to the huge amounts of waste that take many years to decompose. As alternatives to such synthetic plastics, polysaccharides derived from renewable sources are receiving increasing attention. However, as a rule, polysaccharides are not suitable for thermoplastics processing techniques. The aim of the research is to create a biodegradable products from renewable sources that would have similar properties to commonly used plastics. It’s planned to investigate the possibility to reduce hydrogen bonding by modifying polysaccharides and maintaining their biodegradability at the same time as well as explore the possibilities to use materials and their composites for replacement of conventional plastics. Research would provide new knowledge on the possibilities to control inter- and intramolecular interactions of polysaccharides and their composites by chemical and physical modification methods in order to obtain products with optimal thermal and mechanical properties

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Research Topic Summary.

The aim of this project is development of easy obtainable organic semiconductors specifically for OPDs which can allow to further significantly improve their photodetection properties and can lead to broadening of the fields of their applications. New series of organic electroactive compounds will be designed and synthesised. Molecular design of these materials is based on donor-acceptor strategy selecting rigid and planar electron-donating moieties and multi-cyano groups that potentially may exhibit absorption of intramolecular charge-transfer states in visible/near infrared regions. Due the planarity and rigidity of structures of the compounds, non-dispersive charge transport and high charge mobilities exceeding 10-3 cm2/Vs are expected.

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Research Topic Summary.

There is sufficient scientific evidence that increasing daily intake of dietary fibre to 35 g might be a reasonable target that would be expected to reduce risk of premature mortality in adults with diabetes. When looking for new sources of dietary fiber, you need to consider the basic requirements - edible, cheap, sufficient amount. It is also important that dietary fiber have hypoglycaemic activity and hypolipidemic activity, as demonstrated by in vitro studies. To the best of our knowledge, there are no reports on the use of vegetable waste for the development of dietary fiber products. The aim of this study was to develop dietary fiber with hypoglycemic activity and hypolipidemic activity using vegetable waste.

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Research Topic Summary.

3D printing technology is widely used in the development of foods with a positive impact on consumer health. This technology is based on the extrusion of food (bio) ink onto target plates according to a predetermined plan. To create a better resolution 3D dimensional object, food ink with the specific rheological properties is required. For customized food with health-nutritional needs, it is important to model its’ composition, which includes the selection, compatibility and stability of the appropriate carcass-forming nutrients and its’ filling compounds, micro-organisms, mineral elements, etc. One of the promising directions of application of 3D printing technology is 3D printing of foods that improve intestinal health. The aim of this study is to develop a bio-ink that contains probiotics and prebiotics that would have a positive effect on the intestinal health of consumers.

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Research Topic Summary.

Synthetic biology and metabolic engineering offer the potential for synergistic development of microorganisms with novel biosynthetic pathways to valuable chemicals from these sustainable sources. The development and optimization of such a biosynthetic pathway is still problematic due to the lack of high-throughput methods to select for large libraries of genetic variants and to improve bioproduction. A genetically encoded biosensor is an effective tool to address this problem, as it can be used to measure metabolite concentrations directly and without interrupting the bioprocess, paving the way for sustainable and economically viable biorefining. The proposed project aims to develop and apply genetically encoded biosensors for the discovery and engineering of efficient biocatalytic processes for the degradation and valorisation of lignin, as well as for the production of lignin degradation products, phenolic acids.

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Research Topic Summary.

With the recent intensive development and deployment of high-technologies such as microelectronics, optoelectronics, nanotechnology, or biotechnology, the need for flexible production of precise and small polymeric parts has been growing rapidly. Optical 3D printing (O3DP) technology is very suitable for this, as it stands out from other technologies by high speed (up to s and min) and accuracy (up to nm and µm), mild process conditions (room temperature), and low environmental pollution (no need for solvent, less waste). In this technology, the substitution of petroleum-derived materials with those derived from renewable materials would provide ecological and economic benefits, because of the latter's lower toxicity, better recovery and recycling options, reduced dependence on limited and increasingly expensive fossil resources, and lower greenhouse gas emission. Currently, most commercial photosensitive resins for O3DP are composed of synthetic materials derived from petroleum, although the demand for renewable materials for this technology is huge. Furthermore, there is a serious lack of knowledge on the influence of the chemical composition of plant-derived photoresins and the process conditions on the photocuring kinetics and the different properties of O3DP polymers. This work will help fill the knowledge gaps mentioned and offer new renewable materials for the O3DP market. The aim of this work is to synthesize and investigate new photopolymers from renewable raw materials that would be suitable for O3DP technology. Various plant-derived compounds will be used for the synthesis of polymers, such as monomers derived from hemicellulose and lignin, vegetable fats, etc. During the work, photosensitive resins of various plant-derived monomers will be developed, their composition and photopolymerization conditions will be optimized, photocuring kinetics will be investigated, the structure, rheological, mechanical, thermal properties, biodegradability, etc. of the obtained polymers will be investigated. The dependence of the structure and properties of the formed polymers on the chemical structure and content of the starting materials in the mixture will be investigated. Selected combinations of plant-derived materials will be tested on O3DP devices and offered for commercialization. During doctoral studies, internships are planned in the laboratories of universities and research centers in France, Finland, Spain, and / or other European countries. The research results will be published in peer-reviewed scientific publications in journals indexed in the Web of Science database with a high impact factor and presented at international conferences or, upon receipt of patentable results, will be patented.