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Photochemical degradation of dissolved organic matter - the kinetics of insoluble particles
ŠAVRDOVÁ, Tereza
This bachelor thesis deals with the kinetics of the formation of insoluble substances. In the theoretical part we will deal with photochemistry, kinetics and organic substances. What forms of aluminum and iron can be found in aquatic environments with different pH values. In the experimental part we will examine the kinetics of the formation of insoluble particles in water after photochemical irradiation. We will find out how it changes the concentration of aluminum, iron and carbon according to the length of irradiation and how pH can affect the final result.
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Humic substances as transport medium for plant nutrition
Vlková, Markéta ; Solná, Irena (referee) ; Klučáková, Martina (advisor)
This bachelor thesis treats about humic matters and their application in agriculture by means of hydrogels transport medium. It studies progressive releasing of substances, which could be used as more common nutrition for plants, prepared from superabsorbent polymers. Research was implemented in collaboration with industrial partners. The substances are synthetically made of sodium Lignohumate and mixture of industrial fertilizer called NPK. Released substances were characterized by using some methods. First, there were measured qualities, which didn’t specify released compounds, like swelling, conductivity, pH and absorption of hydrogels with different wavelengths. More details came with methods ICP-OES and ion chromatography. Hydrogels which contained both mixtures of matters written up, were studied in water solution for 5 weeks and every week all characterization were measured. From the results we can see that both of the mixtures decrease ability of hydrogel’s swelling, mainly NPK. Measuring of absorption showed that the most of the substances released from sodium Lignohumate were from hydrogels without NPK. By other measuring, we noticed realizing of potassium and phosphorus elements. The most of them were from hydrogels containing NPK. By measuring ion chromatography, we found chloride, phosphoric, sulfuric and nitric ions in solution.
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Printed light dosimeter for galleries
Škarvadová, Adéla ; Klusoň, Petr (referee) ; Veselý, Michal (advisor)
This bachelor thesis deals with the lighting of the gallery space and the measurement of light intensity inside. The subject of the experimental study are photosensitive composition for the production of disposable printed and thin-film dosimeters for galleries and museums. Kinetic color change of the two systems using two dyes and calibration components was examined. The composition for printing was optimized and dosimeters were prepared with a wide range of light exposure causing a significant color change of the dosimeter, and that from 1,7 klx•h to 200 klx•h.
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Catalytic oxidation of VOC on commercially available catalysts
Osička, Tomáš ; Jecha, David (referee) ; Brummer, Vladimír (advisor)
The main topic of this thesis is a catalytic oxidation which belongs to a group of modern technologies for removing emission of CO and VOC from waste air. In the introduction of this thesis, the basic concepts are defined. Further the legislative requirements associated with VOC emissions, emission limits and conditions are summarized. Described destructive and non-destructive methods for removing VOCs from waste gases are also briefly described. Increased attention is paid to the catalytic oxidation as the main theme of the thesis. It was searched for industrial applications where the catalytic oxidation is used. Another chapter is devoted to the theoretical analysis of kinetics of catalytic oxidation reactions. Firstly, the basic types of reactors are described and also material balance and reaction rate for the isothermal and adiabatic reactor. In the experimental part results of performed kinetic measurements on a pilot unit for catalytic commonly used organic solvents (VOCs) using commercially available catalysts were summarized. Pre-exponential factors and activation energies for sprinkling catalysts EnviCat VOC-5565 and EnviCat 55068 for substances ethanol, toluene and acetone were determined. "Light-off" curves for these substances and methane were measured and on sprinkled catalyst EnviCat 55068 and on monolithic catalyst Purelyst PH-304.
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Kinetics of Heterogeneous Processes in Silicate Technologies -Dehydroxylation and Disolution of Clay Minerals
Křečková, Magdaléna ; Kutzendörfer, Jaroslav (referee) ; Kuřitka, Ivo (referee) ; Havlica, Jaromír (advisor)
The first part of the thesis discuss general characterization of heterogeneous processes in silicates. This part is focused on kinetics of heterogeneous processes and mathematical description of reactions time behavior. The other part describes important technologies in silicate industry such as sintering, solid matter decomposition, transition modification, etc. Another chapter deals mineralogy, structure and properties of eminent silicate raw materials. Emphases is given to characterization of clay minerals and their utilising. The experimental part handle the analytic techniques used for investigation of thermal decompostion, dehydroxylation, crystalization of Al-Si spinel phase and sintering process of washed kaolin Sedlec Ia from the region Carlsbad (Czech Republic). Concluding chapter reports on results of experimental work.
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Kinetics of the Coordination Polymerization of -olefins Catalyzed by Nickel Diimine Complexes
Peleška, Jan ; Kratochvíla, Jan (referee) ; Pinkas,, Jiří (referee) ; Petrůj, Jaroslav (referee) ; Cihlář, Jaroslav (advisor)
This Ph.D. thesis is focused on kinetic study of propene and hex-1-ene coordination polymerizations initiated by complex [(2-tBuC6H4)N=C(1,8-naphtalenediyl)C=N(2-tBuC6H4)]NiBr2 activated by simple organoaluminium compounds and on product properties. In first three parts proper activators are chosen in model polymerizations. The attention is paid to the reproducibility of polymerizations and analytical methods. The fourth part is focused on propene polymerization kinetics with the aim to define optimal reaction conditions, especially polymerization temperature and time. The four part concerns also properties of polymers. The fifth and sixth parts deal with hex-1-ene polymerization kinetics conducted at various activator/initiator molar ratios and various catalytic precursor concentrations, to find out kinetic orders with respect to catalyst and cocatalyst concentration. Last part is oriented on detail mechanistic investigation of nickel diimine complexes activation process. Results of measurements in presence or absence of monomer enabled to propose new interpretation of UV-vis spectra based on concrete structures of absorbing species.
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Kinetics of photochromic reactions in thin polymeric layers
Zeman, Vojtěch ; Weiter, Martin (referee) ; Vala, Martin (advisor)
The thesis is aimed to the study of spiropyrane behavior in polymeric matrix of poly(N-vinylkarbazole) (PVK) and poly[2-methoxy-5-(3´,7´-dimethyloctyloxy)-1,4-fenylenvinylene)] (MDMO-PPV). The photochromic transformation of spiropyrane to its isomeric merocyanine form (SPMC) was studied by absorption and emission spectroscopy. It was found, that photochromic reaction is markedly dependent on the environment. In the PVK polymer, which don’t absorb in the visible region, a high yield of photochromic reaction was achieved. Both, absorption and emission spectrums were observed for this system. From the measurement of time dependencies of the fotochromic reaction, the activation energy of the reverse reaction was determined. A different behavior, particularly in emissive spectrums, was found for the MDMO-PPV polymer doped with spiropyrane. Instead of formation of new band of merocyanine, decrease of the polymer fluorescence was observed. Subsequently, we studied the interaction between the polymeric matrix and the photochromic spiropyrane using fluorescence quenching method. On the basis of energy transfer theory, a critical radius of the fluorescence quenching sphere in solution and in solid was determined.
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Automated measurement system for ethene polymerization
Janošík, Zdeněk ; Richtera, Lukáš (referee) ; Přikryl, Radek (advisor)
Thanks to macromolecular chemistry development polymers become essential materials for wide range of applications. Research of catalytic systems used for production of polymers plays a key role in development of new polymer-based materials. The aim of this work was to develop system providing automated kinetic measurement of catalytic systems used in ethylene solution polymerization. The theoretical part of the thesis provides basic overview on chemical process taking part in ethylene polymerization and technical instruments used for its automation. Description of the devised system, its technical solutions and performed experiments used for verification its proper function are presented in the experimental part. Acquired data were compared with published results obtained with the same catalytic systems. Texts are accompanied by schemes, screenshots and photos.
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Kinetics and temperature dependance of cellulose degrading enzymes in the Arctic soils
VAZAČ, Jan
Kinetics and temperature dependance of ?-glucosidase and cellobiosidase was investigated in Arctic soil. These enzymes are key in cellulose degradation, while ?-glucosidase produces the final product of cellulose degradation, the glucose, which si readily available to soil microbes and can influence the CO2 production. The enzymes activities was measured using fluorogenic substrates.
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