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Development of methods for fast soil analysis
Křivánková, Zuzana ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
The submitted diploma thesis aims to extend the use of thermogravimetry for the analysis of organic C and total N contents in soils. The advantages of thermogravimetry in comparison to conventional analytical methods are that it is a versatile technique that provides fast analysis, does not require sample pretreatment and chemicals– and can be used for the analysis of various soil types. The research work performed so far showed correlations between thermogravimetric data and some soil properties. In the past, intact soils exposed to 76% relative humidity (RH) were analyzed by thermogravimetry for these purposes. However, this humidity is problematic to achieve and maintain for most thermogravimeters. Recent work has shown that correlations can be observed in agricultural land exposed to lower RH. Therefore, it can be assumed that a correlation between TG data exists in soils exposed to any RH. TG could then be used to analyze soil properties under any known RH conditions. The aim of this work was to verify this hypothesis and try to incorporate knowledge of RH into the relationships between TG and soil properties. For this reason, intact soils exposed to the relative humidity of 30, 55, and 76% were analyzed in this work. It was demonstrated the dependence between organic C content and mass loss between 320 and 330°C as well as total nitrogen content and mass loss between 410 and 420°C independently of relative humidity. Based on that knowledge, we have derived equations enabling determination of the content of organic C and total N for RH ranging 43% - 76% using mass losses and knowledge of RH. Nevertheless, due to the low number of tested RH, the equations are still only preliminary and need to be improved by analyzing soil samples at a larger number of RH.
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Development and testing of a laboratory unit of membrane distillation
Plachý, Petr ; Repková, Martina (referee) ; Kučerík, Jiří (advisor)
This thesis describes the development and testing of a membrane distillation laboratory unit based on microporous membranes made of polypropylene hollow fibers. For this purpose, a membrane module has been developed that allows easy and fast exchange of membrane bundles. Theoretically, this module enables direct (DCMD), air gap (AGMD), sweeping gas (SGMD) and vacuum (VMD) membrane distillation. The module was used in a laboratory unit that has been designed for testing of the membrane distillation process. This unit has been succesfully used for water distillation. In this work the influence of several operating parameters on distillate production in VMD and SGMD modes has been tested. In addition, the combined effect of feed temperature and flow and module pressure on distillate production has been described.
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Water retention capacity of humic substances
Cihlář, Zdeněk ; Šmejkalová, Daniela (referee) ; Kučerík, Jiří (advisor)
Humic acids were extracted from South Moravian lignit. That humic sample was oxidized by either H2O2 or HNO3. In next step, oxidized humic acids were polymerized by formaldehyde in order to obtain cross-linked structures with improved water retention capacity. Affinity to water and water retention capacity of obtained products were studied by thermal analysis (DSC – differential scanning calorimetry and TGA – thermogravimetric analysis). In order to study above-mentioned parameters two different methods were used. First approach represented sorption of water to humic acids from three controlled humidities, for description of those processes TGA measurement was used. Second study was based on the DSC monitoring of water excess sorption. Results obtained from TGA measurements showed an increasing sorption ability with increasing relative humidity of the environment. DSC measurerents in hermetically sealed containers resulted in an increasing content of water bound by humic acids structures. All the modified samples of humic acids (oxidized as well as oxidized and modified by formaldehyde) gave higher retention capacity in comparion with the parental humic sample.
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Hydration of biochar prepared by using microwave pyrolysis of municipal sludge
Miklasová, Marta ; Komendová, Renata (referee) ; Kučerík, Jiří (advisor)
Microwave pyrolysis represents a possible solution of municipal sludge disposal. One of the final products of pyrolysis is amorphous porous carbon material called biochar, which can be used in agriculture as a soil amendment. As a rule, biochar is hydrophobic, but its addition can lead to an increase in water holding capacity. However, reasons of this improvement cannot be explained only by its high porosity. This thesis aims to contribute to the understanding the interactions between biochar and water under various environmental-relevant conditions such as direct water addition method and water adsorption from ambient air at different relative humidity. The thermo-analytical methods are common for investigation of the relationship between water and organic materials. One of these methods, differential scanning calorimetry, was used in this thesis. The first experiment was focused on measuring of melting enthalpy of freezable water in biochar pores. The results reflect the influence of pore size and properties of ice structure. The extrapolation of concentration dependence to zero enthalpy was used to determine non-freezing water (0,13–0,15 mg·mg-1 biochar), which reflects microporosity of the biochar. The second experiment was focused on the determination of evaporation enthalpy of water from biochar, which is a measure of the strength of water binding in biochar. This value indirectly reflects the mechanisms of the intake and release of water by biochar. Comparing the results for bound and pure water showed that in biochar is water bound weaker about 10–20 %. This led to conclusion that biochar binds water relatively weakly and the water exchange between biochar and soil is fast, despite the biochar hydrophobicity.
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Production and characterization of regenerated humic acids
Uhrová, Anna ; Daniela,, Šmejkalová (referee) ; Kučerík, Jiří (advisor)
Jihomoravský lignit pocházející z dolu Mír v Mikulčicích, Lignit s.r.o. byl přesítován a vybraná frakce byla modifikována tzv. mokrou cestou pomocí dvou oxidačních (HNO3, H2O2) a dvou „amfifilních“ (kyselina octová, kyselina citronová) činidel. Alkalickou extrakcí byly získány jak huminové kyseliny z neupraveného tak předupraveného lignitu (tzv. regenerované huminové kyseliny). Na základě výsledku elementární analýzy byly vypočítány C/O a C/H poměry, které společně s FTIR spektry podaly informaci o stupni alifaticity/aromaticity a dále o stupni oxidace organického uhlíku. Pomocí vysokoúčinné vylučovací chromatografie byla stanovena distribuce velikosti huminových agregátů. K objasnění procesů probíhajících v povrchové vrstvě bylo proměřeno povrchové napětí studovaných roztoků vzorků. Získaná data byla proložena Szyszkowského rovnicí a obdržené parametry poukázaly jak na povrchovou aktivitu jednotlivých huminových kyselin tak i na povahu molekul zodpovědných za snižování povrchového napětí. Pro vzájemnou korelaci dat získaných výše zmíněnými metodami byl použit Pearsonův korelační koeficient.
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Identification of the lables used on the PET bottles for recycling
Zoufalá, Anna ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
Among the most significant sources of contamination in PET recycling belong their labels. The labels of PET bottles are composed of various materials, but the manufacturers are not obligated to declare the labels materials. From the point of view of PET recycling, PVC and PETG labels represent the biggest problem, because they cannot easily be separated from PET, and even a small amount can compromise the end-product of recycling. Therefore, this thesis deals with the identification of labels from PET bottles designated for recycling. For their identification was used FTIR-ATR spectrometer. The analysis revealed that PVC and PETG are frequently used as label materials. In many cases the analysis failed and only used additives could be identified.
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Development of a catalyst for epoxidation of methyl esters
Pham, Tien Thanh ; Krajčovič, Jozef (referee) ; Kučerík, Jiří (advisor)
The diploma thesis is focused on the study of heterogeneous catalysts in the epoxidation of rapeseed oil methyl ester. Epoxides of these components have applications in cutting oils, where they could replace hitherto used oils from fossil sources. Epoxidation is a catalyzed reaction using homogeneous catalysts based on mineral acids. However, they have corrosive properties and they are poorly separated after the reaction. However, this work is focused on the study of heterogeneous catalysts in epoxidation. The reaction products were analyzed by GC, SIMDIS and ATR-FTIR. Advanced analytical methods such as ICP-OES, XRF, XRD, SEM, mercury porosimetry and TPR-H2 were used to determine the composition, structural, textural and reducing properties of the catalysts.
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The development of a TGA-MS based method for determination of microplastics in soils
Šilhánková, Lenka ; Mravcová, Ludmila (referee) ; Kučerík, Jiří (advisor)
Plasty, pronikající do životního prostředí ať už neúmyslně či záměrně, mohou být fragmentovány za vzniku částic v řádu mikrometrů (tzv. mikroplastů) a znečišťovat tak půdní systémy. Doposud vyvinuté analýzy pro stanovení mikroplastů v půdách jsou především zaměřeny na kvalitativní stanovení, nicméně i jejich provedení se zatím stále potýká s různými úskalími. Navíc, téměř všechny tyto analýzy vyžadují časově náročnou předúpravu vzorku. V této studii jsme se zaměřili na vývoj nové analytické metody pro kvantitativní stanovení mikroplastů polyvinylchloridu (PVC) a polystyrenu (PS) v půdách bez předchozí úpravy vzorku pomocí termogravimetrické analýzy spojené s hmotnostní spektrometrií (TGA-MS). Pro analýzu byly použity vzorky modelové půdy s nízkým obsahem organického uhlíku, které byly spikovány na výslednou koncentraci 0,23–7 hm% PVC či PS. Vzorky byly pyrolyzovány s teplotním krokem 5 K min–1 až na teplotu 1000 °C. Pyrolýzní plynné produkty byly následně analyzovány s využitím hmotnostního spektrometru. Získaná data byla normalizována pomocí externího standardu (šťavelan vápenatý). Limity detekce se pohybovaly v rozmezí 0,08–5,3 hm% pro PVC a 0,005–0,7 hm% pro PS v závislosti na zvoleném m/z. Limity kvantifikace pak byly 0,3–17,7 hm% pro PVC a 0,002–2,2 hm% pro PS. Výsledky dokazují, že spojení TGA-MS může být konkurující semikvantitativní metodou pro stanovení mikro-PVC a mikro-PS v půdě s nízkým obsahem organického uhlíku.
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Characterization of regenerated humic acids
Ivancová, Anna ; Ing. Daniela Šmejkalová,Ph.D. (referee) ; Kučerík, Jiří (advisor)
The work deals with the physical characterization of humic substances, namely potassium and ammonium salts of regenerated humic acids extracted from South-Moravian lignite. The regeneration of lignite was based on the oxidation of lignite by means of nitric acid and hydrogen peroxide. Obtained samples of humic acids were analyzed by elemental analysis, which confirmed that the regeneration changed the distribution of elements in respective humic acids. Diluted aqueous solutions of humates were further analyzed by densitometer and high resolution ultrasonic spectroscopy. Obtained data were used for the determination of the compressibility and hydration. The relationship between those two parameters and way of humic acids preparation was discussed.
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The forensic analysis of soil by FTIR and NIR with multivariate analysis
Nawrath, Pavel ; Kučerík, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This diploma thesis is about forensic multivariate soil analysis in the localities Ostrava and Třinec. A total of 52 samples were taken in the areas near metallurgical companies. These samples were measured for concentrations of chromium, manganese, copper, nickel, lead, mercury and zinc. Mercury concentration was analysed using AMA 254 device. The remaining metals were determined by flame atomic absorption spectrometry (F–AAS). Additionally, IR spectra were acquired by Fourier transform infrared spectroscopy (FTIR) using diffusion reflectance technique (DRIFT). In the end the results were used to create correlation models and statistical models of PCA (principal component analysis) methods with CA (correlation analysis).
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