|
|
Influence of biodegradable polymers microplastics on properties of soil organic matter
Denková, Pavla ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
The microplastics contamination is an issue observed in all environmental compartments. Currently, the trend is to replace the synthetic polymers by biodegradable ones, which are expected to degrade faster due to omnipresent microorganisms. However, this assumption may not correspond with the reality. In nature, biodegradation can last long or not whatsoever and the microparticles of biodegradable polymers can remain in soil the same way as particles of synthetic polymers. The effect of microparticles of biodegradable polymers on soil´s biota has already been studied, but the effect on the properties of soil and water in the soil has not been elucidated yet. This thesis deals with the influence of microparticles of biodegradable plastics on the physico-chemical properties of soil organic matter, especially on the behavior of water in the soil system under arid and semiarid conditions. Microparticles of poly(R-3-hydroxybutyrate), abbreviated as P3HB, were used as a model biodegradable polymer and were introduced into the soil in various concentrations. To determine the evaporation enthalpy of water and stability of water bridges that affect (stabilize) the physical and chemical structure of soil organic matter Differential Scanning Calorimetry (DSC) was used. Simultaneously was also measured their effect on water holding capacity of soil organic matter. Under experimental conditions, P3HB microplastics were found to reduce evaporation enthalpy, which facilitates drying of soil organic matter. Nevertheless, their effect on final water holding capacity was relatively low. Besides, we observed a negative effect on the stability of water molecule bridge that connect segments of soil´s organic components. Thus, P3HB microparticles in soil could pose a risk due to their influence on the water retention mechanism in soil under arid and semiarid conditions.
|
|
|
Water-cation bridges in soil organic matter
Starostová, Anna ; Komendová, Renata (referee) ; Kučerík, Jiří (advisor)
Degradace půdy zasolováním, zvyšující se teplota a následný úbytek mnonžství srážek v posledních letech vedou k rozšiřování aridních a semi-aridních oblastí (v současnosti pokrývají třetinu pevniny Země). Navíc představují globální environmentální problémy, které, pokud se nebudou správně řešit, můžou vést k vážné celosvětové krizi. V této diplomové práci jsme propojili tato témata a zaměřili se na lepší porozumění role sodných kationtů na vazbu vody v půdní organické hmotě v aridních a semi-aridních podmínkách. Náš cíl byl prozkoumat proces vzniku a stabilitu vodních molekulových můstků a vodních-kationických můstků v půdní organické hmotě, sílu vazby a množství vázáné vody v půdě za využití diferenční kompenzační kalorimetrie. Nasycení sodnými kationty bylo studováno ve dvou koncentračních oblastech. Na simulaci přirozených podmínek v půdách bylo použito nasycení vazebných míst sodnými kationty do 100% a nasycení nad 100% reprezentovalo vysoce zasolené půdy. Výsledky potvrdily význam schopnosti půdy získávat vodu ze vzdušné vlhkosti, podíl vody v půdě vzrůstal s relativní vlhkostí. Vyšší podíl vody v půdě pak způsoboval snížení síly vazebných interakcí, což bylo interpretováno jako fakt, že rovnováha mezi půdní a vzdušnou vlhkostí vede k optimální vlhkost půdy. Přítomnost sodných kationtů ve vzorcích do nasycení 100% měla na množství vody zanedbatelný vliv, ale v přesycených vzorcích umožňovala navázání většího množství vody. V přesycených vzorcích bylo také pozorováno zvýšení síly vazebných interakcí mezi půdou a vodou, což vede k její větší zádrži. Molekulové můstky byli stabilnější ve vzorcích, které obsahovaly Na+. Nejvyšší stabilita byla pozorována u 10% nasycených vzorcích, další zvyšování Na-saturace pak již vedlo k snižování stability molekulových můstků. Hlavním výstupem práce je, že tvorba vodních-kationických můstků stabilizuje půdní strukturu a že má vlyv na sílu a množství vody vázané v půdě, což představuje klíčové aspekty kvality půdy. Je potřebný rozsáhlejší výskum tohoto tématu, aby získané výsledky pomohli optimalizovat půdní manažment v aridních oblastech a také v ostatních oblastech, kde dochází k degradaci půdy.
|
|
|
Stability of soil organic matter and humic substances
Nováková, Šárka ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on changes of stability in organic matter by extraction in different agents. Two soils of a different type and isolated humic acids were used for stability determination. Extraction agents were selected usually used for soil metal extraction, and a changes in the structure of the organic matter was observed. Samples were characterized using FTIR analysis and elemental analysis, the extracts were measured by UV-VIS spectroscopy, absorption ratios E2/E3, E4/E6 were discovered, dynamic light scattering were determined for particle size distributions. Next part of the thesis was the assessment of the change of thermal stability using thermogravimetric analysis and differential scanning calorimetry, degradation temperatures of the extracted samples were discovered and compared with the original samples.
|
|
|
Relationship between thermo-oxidative stability and soil quality indicators
Svatoň, Karel ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
This diploma thesis focuses on the use of thermogravimetry as quick and low-cost method in the analysis of soil quality. Most of the currently used methods for analyzing some soil properties are, unlike thermogravimetry, demanding especially for pretreatment and analysis time. Previous research has shown an interesting correlation between thermogravimetry data and some soil properties, but to obtain these correlations, it is necessary to keep the analyzed soils at 76% relative humidity. The aim of this work was to determine whether similar correlations can also by achieved at lower relative humidities. Therefore, soil samples in this work were thermogravimetrically analyzed at 43% relative humidity. That humidity is closer to laboratory conditions and it is also easier to be reached by most of commercially available thermogravimeters. Next aim of this thesis was to find whether thermogravimetric data correlate with other soil properties, especially microbiological indicators of soil quality. Results showed that thermogravimetry of soil samples correlates with standard methods even at 43% humidity. Furthermore, it was found that they also correlate with selected microbiological parameters, such as anaerobic ammonification or urease activity. These results suggest the possibility of using thermogravimetry analysis at broader spectrum of soil properties, without the need for pretreatment of samples and at different (relevant) soil moisture.
|
|
|
Behaviour of diclofenac in soil systems
Šmerdová, Kateřina ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
In these days, a large amount of drugs are not completely removed in wastewater treatment plants, than it enters watercourses and then it leaks into soils. These substances are not natural in the environment, so they can have a negative effects here. This is very important to study the behavior of foreign substances in the environment. In this thesis the sorption and desorption behavior of the commonly used drug diclofenac in the soil system was monitored. The rate of sorption and desorption was determined from the change in diclofenac concentration analyzed by UV-VIS spectrometry. Changes in pH and conductivity were also monitored. Diclofenac showed good sorption properties in all the concentrations. There was no desorption or just a minimal desorption, that indicating a strong bond between diclofenac and soil and less leachability into the soil fusion. The results of this thesis showed, that even if diclofenac leaks into the environment, it is mostly adsorbed into the soil. This is largely positive, because diclofenac is practically harmless in the soil and due to the strong bond it also persist there.
|
|
|
Stability of Soil Organic Matter
Heldesová, Michaela ; Doskočil, Leoš (referee) ; Kalina, Michal (advisor)
This bachelor thesis summarizes available information about current research of soil organic matter stability and it divides them into two logical units. The first part includes environmental, physical and chemical factors, including human activities, which affect the stability or decomposition of soil organic matter. The methods used for the study of organic matter in the soil are summarized in the second part of this thesis. There the attention is paid to the accumulation of organic matter in specific pools, the ways of extraction of organic compounds and the use of quantitative and qualitative analytical methods to describe various characteristic of organic matter.
|
|
|
Interaction of drugs with soil organic matter - calorimetric study
Papko, Nadezhda ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focused on the study of the interaction of soil organic matter with selected drugs using isothermal titration calorimetry. Two fulvic acids and drugs were used in the experiment: ibuprofen, pyridine sulfate and diclofenac. The scope of the work was to test the method for studying the interactions between fulvic acids and drugs and to optimize it for specific humic substances and drugs. Isothermal titration calorimetry includes the possibility to determine very important thermodynamic parameters, which were determined during the measurement of the bachelor's thesis. The main goal was to measure and assess whether the interactions take place and what the thermal effects are.
|
|
|
Correlation of Thermoanalytical Data with Primary Properties of Humified Substrata
Kislinger, Jiří ; Šimon, Peter (referee) ; Tesařová, Marta (referee) ; Schaumann, Gabriele (referee) ; Pekař, Miloslav (advisor)
Tato dizertační práce je napsána jako termoanalytická studie humifikovaných substrátů, tj. huminových látek a půdních vzorků, získaných z několika různých zdrojů tak, aby byl pokryt co nejširší rozsah primárních charakteristik. Práce hledá lineární korelace (s využitím Pearsonova korelačního koeficientu) mezi kinetikou termo-oxidační degradace (sledovanou pomocí termogravimetrie (TGA) a vyjádřenou konverzním časem stanoveným neizotermickou izokonverzní metodou) a standardními charakteristikami, jako je množství aromatického a karboxylového uhlíku přítomného v huminových látkách stanoveného spektroskopií nukleární magnetické rezonance (NMR). Hlavním cílem této práce je objasnit proces termo-oxidační degradace humifikované části přírodní organické hmoty a hledat závislosti mezi primární a sekundární strukturou huminových látek. Dalším úkolem je nalezení korelace mezi termogravimetrickým úbytkem hmotnosti půdních vzorků a jejich mikrobiální stabilitou měřenou v laboratorních experimentech jakožto půdní respirace (tedy uvolňování oxidu uhličitého). Účelem je zjistit, zdali vzájemné propojení vůbec existuje, a objasnit jaké druhy procesů, které provázejí půdní respiraci, je možné jednoduše odhalit pomocí TGA. Výsledky práce skýtají detailnější pohled na termickou analýzu půdních vzorků a jiných humifikovaných materiálů. Hlavním přínosem této práce je prezentace vyskytujících se aplikací termické analýzy pro charakterizaci půdní organické hmoty a dále také příspěvek k rozvoji aplikací technik termické analýzy v půdní vědě.
|
|
|
Transport of pharmaceuticals in soil systems
Janebová, Denisa ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
Drugs have a negative effect on nature. If they do not degrade in wastewater treatment plants, they can contaminate lakes, rivers and even drinking water. However, the soil contains soil organic matter, which has chelating properties and can prevent the migration of the drug. The aim of this bachelor thesis was to map the transport of the selected drug in the soil column and try to determine its diffusivity. Sulfapyridine was chosen for transport. Sulfapyridine belongs to a group of sulfonamide antibiotics that are often detected in the environment. It is mainly used in veterinary medicine to treat various infections. The partial goal was to describe the basic properties of the soil depending on the depth of the soil layer. The drug concentration profile in the soil column was determined by UVVIS spectrometry in soil extracts. The following reagents were used for leaching: distilled water, as a pure solvent without the presence of other substances, tap water as a model reagent replacing the soil solution and magnesium chloride solution, which is used for soil extracts of freely moving and ionically bound substances in the soil.
|
|
|
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.
|
guest ::
