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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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Determination of moisture content in electrical insulating materials
Šebesta, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work is based on determination of moisture content in electrical insulating materials materials and ways to measure the moisture. In the theoretical section describes the methods of thermal analysis, and subsequently described in detail Thermogravimetry method, which is used in the measurement. Measurements are made using the Moisture Analyzer RADWAG 60 W/H connected with a PC, using a variety of samples from inorganic to organic. A great variety of samples was chosen because of demonstrations thermogravimetric methods and a better understanding of wetting and drying of different materials.
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Microcalorimetric study of bacterial degradation of oil and its products
Bola, Tomáš ; Benešová, Pavla (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with a study of the oil degradation as one of the possible products of petroleum using bacterial stems Pseudomonas Putida a Pseudomonas Chlororaphis. The work is motivated by the research of usability of a method which has not been used for those purposes so far – calorimetric analysis. Using IČ spektrometry (ATR), calorimetry and UV-VIS spectrometry was studied a degree and a character of interactions. Calorimetric analysis showed that the Pseudomonas Putida has bigger abbility of the degradability than Pseudomonas Chlororaphis. There was also detected that the optimal concentration for more effective degradation of oil fuel is 5 g/l and 20 g/l. By measurement of the absorbance deppending on time was verified that the bigger is the concentration of the sample, the higher is the resulted absorbance. Using UV-VIS analysis was determined a quantity of biomass. Using IČ spectometry in the ATR mode (reduced reflectance) was detected structure of the sample and also verified that the bacterial cultures Pseudomonas Putida and Chlororaphis degradated entire amount of petroleum.
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Analysis of rubber materials of gas masks
Koporecová, Zuzana ; Tocháček, Jiří (referee) ; Bálková, Radka (advisor)
The thesis deals with determination the type, composition and structure of rubber materials comming from gas masks produced withing sixteen years. Rubber materials were tested to determine if storage conditions could influence or caused the change in composition and/or the structure. To judge it rubber specimens were exposed to termo-oxidative aging at 75 and 105 °C for 50 ad 20 days, respectively, to obtain data for comparison. Termogravimetry Fourie-transform Infrared Spectroscopy with Attenuated Total Reflection and Differential Scanning Calorimetry were used to characterize composition/structure of tested speciments. Thermo-oxidative aging at 75 °C led to degradation of additives in both types of rubber, at 150 °C also to chemical degradation of rubber network especially in case of NR (glass transition temperature increases with aging time). Neither additives or rubber network was degraded in original rubber specimens. Deterioration of mechanical and, thus, utility properties of gass masks are not supposed any they are recommended to safe usage.
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Influence of biodegradation of polyhydroxyalkanoates on soil properties and composition
Denková, Pavla ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
Biodegradable plastics are presented as a promising replacement for synthetic polymers. In soil, they are expected to be fully degraded by micro-organisms within a short time and to be inherently harmless to the environment. However, this assumption needs to be verified, and it is important to pay attention to the impact on soil´s biota as well as the effect of the biodegradation process could have on soil properties, composition and structure. In this work was studied the effect of biodegradation of poly(R-3-hydroxybutyrate), (P3HB), belonging to the group of polyhydroxyalkanoates, on the structure and physicochemical properties of soil. P3HB particles were mixed in different concentrations with soil in which biodegradation experiments were carried out under different conditions - i.e. with and without growing plant, with and without nitrogen fertilization. After 90 days, were soil analyzed. Thermogravimetry was used to determine the amount of residual non-degraded micro-bioplastics and to determine the effect of biodegradation on the properties of soil organic matter. Differential scanning calorimetry provided information on the effect of biodegradation on the evaporation enthalpy of adsorbed water from the soil, while the amount of water in the soil was also determined. Furthermore, the effect on field water holding capacity was determined and sieve analysis of individual samples was performed to characterize the effect of biodegradation on soil particle size distribution. Biodegradation conditions were shown to affect not only the rate of biodegradation but also some soil parameters. As expected, biodegradation of P3HB was proved to be faster in a nutrient-rich environment. In contrast, lack of nitrogen in soil with growing plant caused a decrease in the evaporation enthalpy of water and a reduction in the amount of water in soil, which can lead to easier soil drying and cause stress conditions for plant growth. Increased soil particle aggregation was observed in all sample series with P3HB compared to soils without P3HB addition.
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Identification of PET particles in soils and their influence on the environment
Šudomová, Lucie ; Svěrák, Tomáš (referee) ; Slovák, Václav (referee) ; Kučerík, Jiří (advisor)
This thesis is focused on several issues connected with plastics and their impact on the environment. Although plastics are produced for a relatively short time, they have taken a dominant position in almost all industries and aspects of everyday life. However, this causes significant challenges related especially to the waste management. If plastics are not handled properly, they can contaminate the environmental compartments where they are gradually defragmented and degraded, and macro and microplastics are formed. Both qualitative and quantitative analysis of microplastics in soil is a big challenge. In this work, it is introduced a new method based on mutual relationships between soil components called Soil Universal Model Method (SUMM). The method allowed to identify and quantify some types of microplastics in the untreated soil. It appeared to be effective in the analysis of PET, PVC and PP. A pilot study on the influence of PET microplastics on soil revealed negative effects, which include soil organic matter deterioration and faster desiccation. In addition, it was observed a gradual assimilation of PET into the soil matrix, and possible degradation, in particular at low pH values. To identify the origin of PET fragments occurring in nature it was developed a method based on PET thermophysical properties (determined using Differential Scanning Calorimetry, DSC) and advanced statistical methods. This method appeared to be effective also for the assessment of PET quality in recycling loop and classifies the PET into four groups. It was also found that controlled thermal degradation under laboratory conditions does not correlate with natural PET degradation (aging). A method based on spectroscopic parameters (FTIR) is also presented here, but it did not achieve such unambiguous results as using DSC, because it determines the molecular structure of the polymer, which proved to be insufficient for identifying changes during the PET recycling cycle.
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Influence of bioplastic biodegradation on soil properties
Stanislavová, Veronika ; Zlámalová Gargošová, Helena (referee) ; Kučerík, Jiří (advisor)
Biodegradabilné polyméry sa na trhu stávajú čoraz populárnejšími, a to najmä v poľnohospodárstve, kde sa vďaka svojim priaznivým vlastnostiam používajú ako nátery a mulčovacie fólie. V tejto štúdii bol skúmaný vplyv poly-3-hydroxybutyrátu (P3HB), vnútrobunkového bakteriálneho polyméru, na rôzne vlastnosti pôdy vrátane fyzikálnych, chemických a biologických parametrov s cieľom posúdiť jeho potenciálne využitie v poľnohospodárstve. Výsledky ukázali, že P3HB mal negatívny vplyv na obsah sušiny v pôde, nadzemnú biomasu a spôsobil mierne zníženie pH pôdy. Okrem toho sa aktivita vybraných enzýmov výrazne zvýšila, keď sa P3HB aplikoval samostatne alebo došlo k ešte väčšiemu nárastu v kombinácií s niektorými pôdnymi doplnkami. Výsledky sa líšili v závislosti od použitého pôdneho doplnku. Účinky boli buď negatívne, neutrálne alebo pozitívne. Na posúdenie miery biodegradácie P3HB, vplyvu P3HB na organickú hmotu a zadržiavanie vody sa použila termogravimetrická analýza. Bolo preukázané, že prítomnosť organických doplnkov ovplyvnila rýchlosť degradácie P3HB a iných organických látok v pôde. Okrem toho aplikácia P3HB do pôdy viedla k inhibícii rastu rastlín (Zea mays L.). Pridanie zmien do pôdy pred aplikáciou P3HB tento účinok zlepšilo len okrajovo. Dospelo sa k záveru, že biodegradácia P3HB podporovala mikrobiálnu aktivitu, čo mohlo v konečnom dôsledku negatívne ovplyvniť dostupnosť esenciálnych živín v pôde. Okrem toho výsledky z termogravimetrickej analýzy naznačujú, že kombinácia P3HB a biouhlia by mohla prispieť k lepšiemu zadržiavania vody v pôde.
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Influence of titanium dioxide nanoparticles on soil properties
Zoufalá, Anna ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
This masters thesis deals with the influence of TiO2 nanoparticles on soil properties. Even though synthetic nanoparticles pose potential environmental risk, their impact on the environment is not researched enough. TiO2 nanoparticles are one of the most used and widespread nanoparticles and contamination of the environment with these nanoparticles is inevitable. One of the properties, thanks to which these nanoparticles are used, is the possibility of photocatalysis when the nanoparticles are illuminated with light in the UV wavelength. During this process, especially in the presence of water, highly reactive radicals are formed, which can oxidize organic compounds, which is mainly used for the degradation of organic pollutants. Therefore it is possible that in soil contaminated with TiO2 nanoparticles photocatalytic degradation of soil organic matter could occur. On the other hand, it is possible that polymerization reactions occur too. Thus the aim of this work is to clarify which processes occur after irradiating soil contaminated with TiO2 nanoparticles. To asses the impact of TiO2 nanoparticles and UV irradiation were caried out experiments during which soil contaminated with TiO2 nanoparticles was irradiated at different humidities. These samples were analyzed using thermogravimetry and FTIR spectrometry. No changes caused by TiO2 nanoparticles and UV light were detectable using thermogravimetry. Data acquired from FTIR spectrometry were processed using two different statistical methods – correlation analysis and principal components analysis. Correlation analysis was found not to be suitable method of data evaluation for the purpose of this work. Principal components analysis proved, that higher concentration of nanoparticles (5 wt. %) in combination with UV light does have impact on the composition of soil organic matter and its decomposition occurs mainly.
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Study of hydration of biocolloids
Hývnarová, Lucie ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
The subject of this master’s thesis was to examine the hydration properties of selected biocolloids. Specifically, humic substances (fulvic and humic acids), hyaluronic acids in three molecular weights, dextran and chitosan were investigated. Hydration properties of selected biocolloid substances were studied by various methods. The influence of water content during the dissolution of substances and the different time for which water acted on biocolloids were studied. Differential scanning calorimetry DSC measurements resulted in enthalpies and crystallization and melting points. Heat fluxes resulted in the use of perfusion calorimetry. TGA thermogravimetric analysis was used to determine the moisture content of the bioolloids used, after measuring the perfusion calorimeter.
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Influence of soil pretreatment on the determination of its properties using thermogravimetry
Ragačová, Lucia ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
This diploma thesis focuses on the influence of soil pretreatment on the determination of its properties by the method of thermogravimetry, which allows the soil sample to be analyzed as a whole. The aim is to clarify how soil preparation affects the results of TG soil analysis. Soil preparation can have a major impact on its quality and thus disrupt the interrelationships of soil components that have been formed as a result of long-term pedogenesis. In this thesis, therefore, the original soils were compared with the soils, which were grinded using a ball mill before the analysis, which represented a very intensive intervention in the soil structure and was therefore a mechanically disturbed soil. A modified method of deriving weight loss has been used to evaluate the issue. The data obtained were divided into 10°C thermal intervals, in-between which the loss of weight of the individual intervals were identified. The impact of soil milling on its determinability in relation to the total carbon and nitrogen content in the soil have been compared through the correlation of data obtained from elemental analysis and TG data. Subsequently, we focused on comparing the interrelationships of the equations of ground and unground soil samples, based on the theoretical equations of the issue. As a final look, we chose autocorrelation of TG data for the obtained ground and unground samples. The results of the examination have shown that even though grinding of samples represents a very intensive intervention into the soil structure and thus the soil is mechanically disturbed, such sample preparation has only a minimal effect on the determinability of soil properties.
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