|
|
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.
|
|
|
Nanoparticles of platinum metals in the environment
Berka, Michal ; Kučerík, Jiří (referee) ; Komendová, Renata (advisor)
Platinum nanoparticles, mainly released from automotive catalysts, pose a potential risk to the environment. The aim of this bachelor thesis is to investigate the effect of platinum nanoparticles on soil properties at different humidities. Specifically, how nanoparticles affect the stability of hydrogen bridges, the stability of aliphatic crystals, and water retention in soil. For the analysis of relations between platinum nanoparticles, water and soil, a method of thermal analysis was used, namely differential scanning calorimetry. The theoretical part is devoted to the general introduction to platinum metals and nanoparticles. And the preparation of nanoparticles, their characterization and their properties. The result of the experiments is that platinum nanoparticles affect the soil properties relatively significantly.
|
|
|
Optimizing of Polymer Surface Treatment for Microscopic Examination
Horská, Pavlína ; Poláček, Petr (referee) ; Bálková, Radka (advisor)
Supramolecular structure of eight commercial types of iPP, its blends with poly(L-lactide) (PP-PLLA) and copolymers with ethylene-propylene rubber (PP-EPR) together with four types of polyethylene (LDPE, HDPE) was uncovered and observed in this work. The spherulitic structure of iPP and PE homopolymers and PP copolymers was uncovered by etching of six different solutions of mineral acids with KMnO4 and by dissolution in four selected solvents. The latter was found to be ineffective. The structure of PP-PLLA blends was uncovered only after recrystallization (the change of structure by annealing and cooling rate). The uncovered crystalline structure was observed directly by confocal laser scanning microscope (CLSM) and SEM. Crystallinity together with a size distribution of crystallites was determined by DSC. It was proved that spherulitic supramolecular structure was easy to uncover by chemical etching only for molded samples and for fracture surfaces of injected samples. The efficiency of etchants varied but, generally, the samples with high degree of crystallinity were etched earlier. The etchants containing nitric acid and high content of sulphuric acid uncovered fine details of shperulites with respect to mixtures containing orthophosporic acid. It was also observed that not only the etchant (especially with nitric acid) itself but also its vapors were effective. The structure was revealed later but the appearance was plastic (3D) and the structure was very fine. The supramolecular structure of PP-PLLA blends differed with amount of each component. The ethylene-rubber phase came forth with increasing time of etching while PP spherulites disappeared in PP-EPR samples. CLSM was shown to be very good tool for observing supramolecular structure of studied samples with respect to SEM, which was proved to be entirely unsuitable for polyolefines. DSC is recommended to be performe before uncovering supramolecular structure for basic information about proportion of amorphous/crystalline phase and size of crystallites.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
Nanoparticles of platinum metals in the environment
Berka, Michal ; Kučerík, Jiří (referee) ; Komendová, Renata (advisor)
Platinum nanoparticles, mainly released from automotive catalysts, pose a potential risk to the environment. The aim of this bachelor thesis is to investigate the effect of platinum nanoparticles on soil properties at different humidities. Specifically, how nanoparticles affect the stability of hydrogen bridges, the stability of aliphatic crystals, and water retention in soil. For the analysis of relations between platinum nanoparticles, water and soil, a method of thermal analysis was used, namely differential scanning calorimetry. The theoretical part is devoted to the general introduction to platinum metals and nanoparticles. And the preparation of nanoparticles, their characterization and their properties. The result of the experiments is that platinum nanoparticles affect the soil properties relatively significantly.
|
|
|
Optimizing of Polymer Surface Treatment for Microscopic Examination
Horská, Pavlína ; Poláček, Petr (referee) ; Bálková, Radka (advisor)
Supramolecular structure of eight commercial types of iPP, its blends with poly(L-lactide) (PP-PLLA) and copolymers with ethylene-propylene rubber (PP-EPR) together with four types of polyethylene (LDPE, HDPE) was uncovered and observed in this work. The spherulitic structure of iPP and PE homopolymers and PP copolymers was uncovered by etching of six different solutions of mineral acids with KMnO4 and by dissolution in four selected solvents. The latter was found to be ineffective. The structure of PP-PLLA blends was uncovered only after recrystallization (the change of structure by annealing and cooling rate). The uncovered crystalline structure was observed directly by confocal laser scanning microscope (CLSM) and SEM. Crystallinity together with a size distribution of crystallites was determined by DSC. It was proved that spherulitic supramolecular structure was easy to uncover by chemical etching only for molded samples and for fracture surfaces of injected samples. The efficiency of etchants varied but, generally, the samples with high degree of crystallinity were etched earlier. The etchants containing nitric acid and high content of sulphuric acid uncovered fine details of shperulites with respect to mixtures containing orthophosporic acid. It was also observed that not only the etchant (especially with nitric acid) itself but also its vapors were effective. The structure was revealed later but the appearance was plastic (3D) and the structure was very fine. The supramolecular structure of PP-PLLA blends differed with amount of each component. The ethylene-rubber phase came forth with increasing time of etching while PP spherulites disappeared in PP-EPR samples. CLSM was shown to be very good tool for observing supramolecular structure of studied samples with respect to SEM, which was proved to be entirely unsuitable for polyolefines. DSC is recommended to be performe before uncovering supramolecular structure for basic information about proportion of amorphous/crystalline phase and size of crystallites.
|
guest ::
