|
|
Problems of plastics and microplastics in FTIR analysis of soils
Stanislavová, Veronika ; Kučerík, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
Microplastics are formed as the result of the fragmentation of plastics. The microparticles are easier to distribute and thus can contaminate the environment. Recently, there has been an increasing interest in the research of microplastics present in the soil system, using different methodologies. The focus of this thesis is the analysis of microplastics in soil using infrared spectroscopy – ATR (attenuated total reflectance) and DRIFT (diffuse reflectance) techniques. This work aimed to evaluate the suitability of the method for the identification of microplastics in soils. Polymers such as polyethylene terephthalate (PET), poly-3-hydroxybutyrate (PHB) and polylactic acid (PLA) were used. In the first part of experimental analysis were microplastics mixed in different concentrations with 3 different types of model soils. The obtained infrared spectra of samples of mixtures (model soil and plastics) were used for statistical evaluation. The second part of the measurement was focused on the monitoring of changes in the spectra of real soils spiked with PET, after exposure to the degradation. After the interpretation of infrared spectra of samples of plastics with real and model soil, it was possible to confirm the presence of the functional groups of each polymer. Based on the measurements, the used techniques were evaluated as inappropriate for the qualitative determination of PLA. The results of the experimental part confirm the accuracy of FTIR (both ATR and DRIFT) for the analysis of microplastics in soil for samples containing PET and PHB.
|
|
|
Involvement of vibrational spectroscopy in the study on interactions of natural organic matter with model environmental pollutants.
Stehlíková, Kristína ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The main objective of this diploma thesis was to verify the potential of using advanced infrared spectra processing techniques – specifically the principal component analysis (PCA) – in order to monitor the interaction of natural organic matter with organic pollutants. Natural organic matter was represented by standard IHSS Leonardite humic acid, while the aromatic dyes methylene blue and Rhodamine 6G and the aliphatic substance Septonex were chosen as representatives of organic ions. Their interactions were monitored using Fourier-transform infrared spectroscopy, the use of which for this purpose was verified in my bachelor's thesis. Principal component analysis was finally applied to the obtained infrared spectra of the formed complexes and prepared blank samples, which helped to reveal spectral changes at first glance unrecognizable in the spectra themselves. It was found out that the most likely mechanism of humic acid interaction with aromatic pollutants is a - interaction, while the electrostatic nature of the interaction is assumed for the binding of aliphatic substances.
|
|
|
Filling of Polyurethanes
Bečka, Filip ; Poláček, Petr (referee) ; Kučera, František (advisor)
Bachelor thesis focuses on preparation of filled polyurethanes, determination of tensile properties, hardness and measurement of IR spectra. Theoretical part is devoted to main components of polyurethane systems and the most common inorganic, particulate filler and summarises knowledge about application of mineral fillers into polyurethane matrix. In experimental part was developed method of application of fillers into polyurethane and test specimens were prepared. Dispersion of fillers into polyol and affected workability was investigated. For examination of test specimens 3 methods were used: FTIR spectroscopy, tensile testing and hardness measurement. FTIR spectroscopy was used to investigate conversion of free isocyanate groups an OH groups. Tensile testing proved toughness of material and tensile modulus was determinated. Conformity of strength and stress at break and also conformity of strain at strength and strain at break was found. No yield point was observed for the specimens. Hardness of specimens was measured by the Shore A method.
|
|
|
Problems of plastics and microplastics in FTIR analysis of soils
Stanislavová, Veronika ; Kučerík, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
Microplastics are formed as the result of the fragmentation of plastics. The microparticles are easier to distribute and thus can contaminate the environment. Recently, there has been an increasing interest in the research of microplastics present in the soil system, using different methodologies. The focus of this thesis is the analysis of microplastics in soil using infrared spectroscopy – ATR (attenuated total reflectance) and DRIFT (diffuse reflectance) techniques. This work aimed to evaluate the suitability of the method for the identification of microplastics in soils. Polymers such as polyethylene terephthalate (PET), poly-3-hydroxybutyrate (PHB) and polylactic acid (PLA) were used. In the first part of experimental analysis were microplastics mixed in different concentrations with 3 different types of model soils. The obtained infrared spectra of samples of mixtures (model soil and plastics) were used for statistical evaluation. The second part of the measurement was focused on the monitoring of changes in the spectra of real soils spiked with PET, after exposure to the degradation. After the interpretation of infrared spectra of samples of plastics with real and model soil, it was possible to confirm the presence of the functional groups of each polymer. Based on the measurements, the used techniques were evaluated as inappropriate for the qualitative determination of PLA. The results of the experimental part confirm the accuracy of FTIR (both ATR and DRIFT) for the analysis of microplastics in soil for samples containing PET and PHB.
|
|
|
Utilization of vibrational spectroscopy in study on interactions between humic substances and organic ions.
Stehlíková, Kristína ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The main objective of this bachelor thesis was to validate the potential of the utilization of vibrational spectroscopy in the study on interactions between humic substances and organic ions. Unmodified (HA) and methylated humic acids (mHA) were chosen as model humic substances and organic ions were represented by methylene blue, rhodamine 6G and Septonex. Firstly, a suitable infrared spectroscopy technique was chosen. The results of optimization measurements showed that spectra with the best resolution can be obtained using the DRIFTS technique. The next part of the thesis discusses the effect of methylation in the structure of humic acids. Significant differences were recorded in mHA compared to the unmodified humic acids. Finally, the spectra of humic acid – organic ion complexes were compared to the spectra of prepared blank samples. It was noted that the spectra of complexes are not only a simple sum of the pure individual substances’ spectra, but also shifts and changes in the intensity of different absorption bands were recorded there. It suggests that non-covalent interactions played an important role in the complexes. Infrared spectroscopy was proved to be a useful method for investigating these interactions.
|
|
|
Use of thin layer chromatography for fractionation and characterization of organic matter isolated from alginite
Solanský, Pavel ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This diploma thesis is focused on the study of structure and physicochemical properties of organic fractions of humic substances, which were obtained by the method of thin-layer chromatography. Humic substances, which were used in this study, were isolated from a sample of Slovak alginite based on the procedure of the International Humic Substances Society (IHSS). The following analytical techniques were selected for the characterization of isolated humic substances: thermogravimetric and elemental analysis, molecular absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR) and steady-state fluorescence spectroscopy. Each organic fraction of humic substances were characterized by molecular absorption spectroscopy (UV/Vis) and steady-state fluorescence spectroscopy. Using steady-state fluorescence spectroscopy, humic substances were found to be composed of fluorophores of humic and non-humic (protein) character. Organic fractions corresponding to the humic fluorophores were characterized by a higher content of oxygen substituents on the aromatic nukleus, a higher degree of aromaticity and also a higher molecular weight. The aim of this diploma thesis was to design and optimize the process of organic matter fractionation for the purpose of detailed understanding of the structure and properties of humic substances, which were isolated from the sedimentary rock alginite. Based on this, the practical applicability of the thin layer chromatography method to significantly reduce the molecular heterogenity of the studied humic substances was evaluated.
|
|
|
Fourier transform infrared spectroscopy on nanostructures
Halabuková, Hana ; Münz, Filip (referee) ; Kolíbal, Miroslav (advisor)
This master’s thesis deals with the plasmon resonance of the nanostructures of several selected tungsten oxides using Fourier transform infrared spectroscopy (FTIR spectroscopy). The physical principles of the plasmonics, the characteristics of the materials used, as well as the principle of operating and measuring on the FTIR spectrometer, are described in the first part of this thesis. The second part is focused on the preparation of samples and performing measurements on the FTIR spectrometer. This part ends by representing the final spectra and the results obtained.
|
|
|
Physicochemical and structural analysis for characterization of native and modified humic acids
Solanský, Pavel ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis is focused on structural and physicochemical characterization of native and methylated humic acid. These samples of humic acids, which were isolated from oxidized brown coal Leonardite, were characterized by thermal and spectrometric methods. The following analytical techniques were selected to determine the structural and physico-chemical changes between native and methylated humic acid: thermogravimetry (TGA), elemental analysis (EA), molecular absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy and last but not least nuclear magnetic resonance (13C NMR). The aim of this bachelor thesis was to find the differences in the structure of selected humic acids and also to verify the suitability of the techniques, which were used to characterize these biocolloid substances.
|
|
|
The Study of the Molecular Structure of Various Forms of Conducting Polymers using FTIR and Raman Spectroscopies
Morávková, Zuzana ; Trchová, Miroslava (advisor) ; Baumruk, Vladimír (referee) ; Matějka, Pavel (referee)
In this Thesis, the structure of thin films formed by a conducting polymer, polyaniline, was studied using mainly infrared and Raman spectroscopies. That led to the study of aniline oligomers. The oligomers play a key role in the formation of thin films and nanostructures of polyaniline. Furthermore, the Thesis deals with the carbonization of various forms of polyaniline (granular polyaniline base, thin films of polyaniline salt, multi-wall carbon nanotubes coated with polyaniline salt or base, polyaniline nanotubes/nanorods prepared in the presence of ethanol). The two topics, aniline oligomers and carbonization of polyaniline, are connected by a paper concerning the carbonization of microspheres formed during oxidation of aniline in alkaline medium. Optical microscopy, transmission and scanning electron microscopy, UV-Vis spectroscopy, spectroscopic ellipsometry, wide angle X-ray scattering and thermogravimetric analysis were used.
|
|
|
Regulation of production of lipids and lipid compounds in yeasts
Rapta, Marek ; Breierová, Emília (referee) ; Márová, Ivana (advisor)
Oleogenic yeasts under appropriate conditions produce and accumulate lipids and lipid-soluble metabolites in high amounts. This attribute is characteristic also for red yeasts that except lipids accumulate also carotenoids – natural pigments used in food industry and dietary supplements. The aim of this diploma thesis was designed as a comparative screening study of production properties of strains Cystofilobasidium capitatum, Rhodotorula glutinis, Sporobolomyces roseus and Sporobolomyces shibatanus. Choosen carbon sources were glucose and glycerol as waste by-product in biofuel industry. The best production properties were found in Cystofilobasidium capitatum and Rhodotorula glutinis. These two strains produced increased amounts of lipids as well as higher amounts of carotenoids. Strains were tested by FTIR spectroscopy that enables high-throughput, uncomplicated and accurate analysis.
|
guest ::
