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The influence of humic acids methylation on the interaction of surface active agents
Bělušová, Anna ; Weidlich, Tomáš (referee) ; Smilek, Jiří (advisor)
The presented diploma thesis deals with the study of interactions between humic acids as the main component of soil organic matter with a model organic pollutant presented by cationic surfactant Septonex (which was expected to interact positively with humic acids due to its charge) through unconventional combination of dialysis and diffusion techniques realized in diffusion cells together with isothermal titration calorimetry capable of elucidating the nature of ongoing reactions from a thermodynamic point of view. The experiments were performed with a humic acid isolated by standard isolation procedure from Leonardite (1S104H) purchased from the International Society for Humic Substances, with humic acids isolated from lignite as well as modal chernozem. The aim of the submited diploma thesis is to assess the influence of carboxyl functional groups in the structure of humic acids to interactions with Septonex. For this reason, said samples of humic acids have been modified by selective methylation of their carboxyl functional groups, which can no longer participate in interactions with ionic substances. Results from diffusion cells and isothermal titration calorimetry confirmed the assumption that Septonex interacted with all types of unmodified humic acids more than with their methylated derivatives. Despite the available literature, it was surprising that the differences in the interaction of humic acids with Septonex were not diametrically different when comparing unmodified humic acids with their methylated derivatives. The extent of these interactions was assessed through the apparent equilibrium constant Kapp determined in the diffusion (dialysis) experiments and from the course of enthalpy curves from isothermal titration calorimetry. After the experiments and their evaluation, it can be concluded that humic acids and Septonex in their interactions, due to their structures, probably apply not only electrostatic interactions, especially through available carboxyl functional groups of humic acids and positively charged hydrophilic parts of Septonex molecules, but also a significant role have a hydrophobic effect, hydrogen bonds and Van der Waals forces.
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Modeling the Impacts of Changes in Waste Management on Key Technologies
Jadrný, Josef ; Suzová, Jana (referee) ; Weidlich, Tomáš (referee) ; Pavlas, Martin (advisor)
The doctoral thesis focuses on waste management planning in the Czech Republic with regard to key technologies. The operation of processing facilities is influenced by strategic documents that reflect the legislative framework of the EU and the Czech Republic. Due to the introduction of new principles and evaluation criteria, it is necessary to regularly update the Waste Management Plan at the state and regional level, according to the Waste Act No. 541/2020 Coll. When creating new strategic documents, emphasis should be placed on the use of available computing tools, inter-regional cooperation and the specific formulation of goals and measures. The individual goals of waste management must be taken into account when operating existing facilities and also when planning the necessary infrastructure. The attention in this text is devoted to the analysis of the current state of waste management in the Liberec Region with a focus on key technologies. The mentioned approaches and recommendations can be further applied to any region of the Czech Republic.
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Effect of chemical modification of humic acids on their interactions with organic ions
Fryšová, Eva ; Weidlich, Tomáš (referee) ; Sedláček, Petr (advisor)
This master thesis deals with the interaction of humic acids with organic ions and effect of chemical modification of humic acids on this interaction. Rhodamine 6G was used as a model organic ion. The interaction were studied by fluorescence quenching, dialysis in diffusion cells and differential UV-VIS spectroscopy. Results showed that the bond between the reactants was not primarily dependent on carboxylic functional groups of humic acids. Fluorescence experiments indicated static quenching mechanism and differential UV-VIS spectroscopy demonstrated the existence of - interactions.
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Transport of humic substances through plant cuticle
Smilková, Marcela ; Salaš, Petr (referee) ; Weidlich, Tomáš (referee) ; Klučáková, Martina (advisor)
Doctoral Thesis is aimed on the transport of liquid preparations chemically based on potassium lignohumate through plant cuticles commonly utilized in agricultural applications. Firstly, the thesis deals with optimization and correct mathematical description of diffusion experiments. Transport (diffusion) experiments have been realized in model hydrogel media based on linear polysaccharide – chemically inert agarose. Diffusion experiments have been realized by two independent approaches (diffusion models) – free diffusion of lignohumate in hydrogel and diffusion pair (hydrogel-hydrogel), where one of these was enriched by lignohumate in contrast with the second one. Plant cuticle, as the major barrier on the leaves, isolated from Prunus laurocerasus, was used as porous membrane in diffusion experiments. The main aim of Ph.D. thesis was the characterization of barrier properties of cuticles, which are the most limiting barrier regulating the transport of lignohumate in/out the leaves during foliar fertilization. These experimental problems have been solved by diffusion experiments and by their proper mathematical description, especially by the determination of fundamental diffusion parameters such as effective diffusion coefficients. These parameters have been used for the modelling of concentration profiles in hydrogels and comparison with experimental data. Significant part of thesis is aimed on the determination of physico-chemical properties of plant cuticles and hydrogels matrixes utilized as model diffusion environment. These characteristics are subsequently correlated with transport (diffusion) parameters. Plant cuticles have been isolated from Prunus laurocerasus leaves and then were characterized by relevant instrumentation notably with respect to their structure and penetration through of lignohumate. Hydrogels have been characterized with respect to mechanical (viscoelastic) (rheology), morphological e.g. porosimetry) and structural (scanning electron microscopy) properties. Mentioned properties have direct link to transport processes ongoing in these materials. Next part of doctoral thesis is aimed on the proper and correct interpretation of experimental results obtained from glass-house experiments. During these experiments, hydrogels based on superabsorbent polymers developed on Faculty of Chemistry, Brno University of Technology, have been used together with commercial preparation – potassium lignohumate kindly provided by co-working commercial subject – Amagro s.r.o. The main aim was the application of lignohumate directly on plants through root system. Results of these experiments should confirm the positive effect on plant growth as well as their positive development. Results obtained from transport/diffusion experiments confirm that the penetration of active compounds (lignohumate) is more efficient in comparison with adaxial cuticles. The kinetics of lignohumate transport is faster for abaxial cuticles. From superabsorbent experiments it is obvious that these play significant role in growth and development of plant and simultaneously positively contribute to creation of suitable conditions for proper microbiological and bacterial activity, which is essential for health soil.
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Material characterization of novel hydrogels containing humic substances intended for pharmaceutical and cosmetic applications
Pavlicová, Renata ; Weidlich, Tomáš (referee) ; Sedláček, Petr (advisor)
This thesis is focused on the development and characterization of hydrogels containing humic substances with possible use in cosmetic and pharmaceutical industries. This work follows on the bachelor thesis, theoretical and experimental part is based on already acquired knowledge. The aim of this work was to develop a literature review focusing on the potential use humic gels in practice and also to enhance the consistency of other active ingredients. Based on this literature review, the main aim was to prepare model humic hydrogels with selected active ingredients and their characterization by basic methods of material analysis. These basic methods were especially rheology and visual assessment of consistency during the preparation, then the samples were subjected process of drying and swelling. Experimental results showed considerable influences during the preparation and composition of each sample, which then reflected in their structure and consistency. Furthermore, it was found that the suitable composition and combination of ingredients form hydrogels acceptable characteristics for further use in cosmetic or pharmaceutical applications.
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The Influence of Microbial Degradation of Biochar in Soil on its Physico-chemical Properties
Kurková, Marie ; Weidlich, Tomáš (referee) ; Kalina, Michal (advisor)
This master‘s thesis studies the different factors that can affect biochar in soil and cause its degradation. These factors include irrigation, root exudates and the action of microorganisms. In the experimental part, the degradation of biochar in the soil environment was studied in two ways, firstly without the action of microorganisms, where the effect of irrigation was simulated by leaching biochar in ultrapure distilled water and model rainwater, and the effect of root exudates was simulated by extracting of biochar in citric acid as a model root exudate of maize sown. The extracted biochar solutions without prior cultivation in soil were characterized by pH, conductivity, UV-VIS analysis and elemental analysis. The biochar residues after extractions were characterized for morphology by SEM, structural differences by FTIR, and organic and mineral content by TGA analysis. The biochar samples after cultivation in soil were subjected to extractions under the same conditions and the same analyses were performed. The effect of cultivation in soil on biochar resulted in a change in elemental composition, a decrease in biochar alkalinity and changes in the ratio of organic matter and mineral fraction were observed. The decrease in pH and conductivity of biochar was mainly related to potassium leaching. The structural and morphological analysis indicated that there is no significant degradation of the structure of the biochar due to washing or cultivation in soil, but there is a partial fouling of the biochar pores by low molecular weight impurities from the soil. These results suggest a short-term action of biochar in soils as a source of nutrients (potassium, phosphorus) and, conversely, a long-term action as a soil conditioner.
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Study on transport of liquid lignohumates through plant leaves and plant cuticles
Rampáčková, Eliška ; Weidlich, Tomáš (referee) ; Smilek, Jiří (advisor)
This thesis deals with the study of transport commercial solution of pottasium lignohumate through the plant cuticles, as the main barriers in transport of active ingredience to plant tissues. The problematics has been studied to obtain the informations about ability of transport liquid active ingredience during foliar fertilization, which became popular in theme of efective utilization fertilizers and reduction their negative impact to enviroment. The aim of this thesis was to optimize technics of diffusion for demanded purposes in the Stokes diffusion cells. As the transport barriers have been used the plant cuticles, that have been isolated by various methods. The ultraviolet and visible spectrometry (UV-VIS) was the analytical method for determination of transported volume of lignohumate and to the mentioned experiments the cuticles of Prunus laurocerasus and cuticles of tomato fruit have been used. The isolated cuticles have been analyzed by optical microscopy, scanning electron microscopy and profilometry. The characterisation of the used solution of lignohumate was also important part of this thesis. It has been used the basic physico-chemical methods and also the advanced methods as tensiometry, size exclusion chromatography with UV detector and differential refractive index detector (SEC-UV-dRI) and thermogravimetry (TGA).
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The Influence of Microbial Degradation of Biochar in Soil on its Physico-chemical Properties
Kurková, Marie ; Weidlich, Tomáš (referee) ; Kalina, Michal (advisor)
This master‘s thesis studies the different factors that can affect biochar in soil and cause its degradation. These factors include irrigation, root exudates and the action of microorganisms. In the experimental part, the degradation of biochar in the soil environment was studied in two ways, firstly without the action of microorganisms, where the effect of irrigation was simulated by leaching biochar in ultrapure distilled water and model rainwater, and the effect of root exudates was simulated by extracting of biochar in citric acid as a model root exudate of maize sown. The extracted biochar solutions without prior cultivation in soil were characterized by pH, conductivity, UV-VIS analysis and elemental analysis. The biochar residues after extractions were characterized for morphology by SEM, structural differences by FTIR, and organic and mineral content by TGA analysis. The biochar samples after cultivation in soil were subjected to extractions under the same conditions and the same analyses were performed. The effect of cultivation in soil on biochar resulted in a change in elemental composition, a decrease in biochar alkalinity and changes in the ratio of organic matter and mineral fraction were observed. The decrease in pH and conductivity of biochar was mainly related to potassium leaching. The structural and morphological analysis indicated that there is no significant degradation of the structure of the biochar due to washing or cultivation in soil, but there is a partial fouling of the biochar pores by low molecular weight impurities from the soil. These results suggest a short-term action of biochar in soils as a source of nutrients (potassium, phosphorus) and, conversely, a long-term action as a soil conditioner.
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Transport of humic substances through plant cuticle
Smilková, Marcela ; Salaš, Petr (referee) ; Weidlich, Tomáš (referee) ; Klučáková, Martina (advisor)
Doctoral Thesis is aimed on the transport of liquid preparations chemically based on potassium lignohumate through plant cuticles commonly utilized in agricultural applications. Firstly, the thesis deals with optimization and correct mathematical description of diffusion experiments. Transport (diffusion) experiments have been realized in model hydrogel media based on linear polysaccharide – chemically inert agarose. Diffusion experiments have been realized by two independent approaches (diffusion models) – free diffusion of lignohumate in hydrogel and diffusion pair (hydrogel-hydrogel), where one of these was enriched by lignohumate in contrast with the second one. Plant cuticle, as the major barrier on the leaves, isolated from Prunus laurocerasus, was used as porous membrane in diffusion experiments. The main aim of Ph.D. thesis was the characterization of barrier properties of cuticles, which are the most limiting barrier regulating the transport of lignohumate in/out the leaves during foliar fertilization. These experimental problems have been solved by diffusion experiments and by their proper mathematical description, especially by the determination of fundamental diffusion parameters such as effective diffusion coefficients. These parameters have been used for the modelling of concentration profiles in hydrogels and comparison with experimental data. Significant part of thesis is aimed on the determination of physico-chemical properties of plant cuticles and hydrogels matrixes utilized as model diffusion environment. These characteristics are subsequently correlated with transport (diffusion) parameters. Plant cuticles have been isolated from Prunus laurocerasus leaves and then were characterized by relevant instrumentation notably with respect to their structure and penetration through of lignohumate. Hydrogels have been characterized with respect to mechanical (viscoelastic) (rheology), morphological e.g. porosimetry) and structural (scanning electron microscopy) properties. Mentioned properties have direct link to transport processes ongoing in these materials. Next part of doctoral thesis is aimed on the proper and correct interpretation of experimental results obtained from glass-house experiments. During these experiments, hydrogels based on superabsorbent polymers developed on Faculty of Chemistry, Brno University of Technology, have been used together with commercial preparation – potassium lignohumate kindly provided by co-working commercial subject – Amagro s.r.o. The main aim was the application of lignohumate directly on plants through root system. Results of these experiments should confirm the positive effect on plant growth as well as their positive development. Results obtained from transport/diffusion experiments confirm that the penetration of active compounds (lignohumate) is more efficient in comparison with adaxial cuticles. The kinetics of lignohumate transport is faster for abaxial cuticles. From superabsorbent experiments it is obvious that these play significant role in growth and development of plant and simultaneously positively contribute to creation of suitable conditions for proper microbiological and bacterial activity, which is essential for health soil.
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The influence of humic acids methylation on the interaction of surface active agents
Bělušová, Anna ; Weidlich, Tomáš (referee) ; Smilek, Jiří (advisor)
The presented diploma thesis deals with the study of interactions between humic acids as the main component of soil organic matter with a model organic pollutant presented by cationic surfactant Septonex (which was expected to interact positively with humic acids due to its charge) through unconventional combination of dialysis and diffusion techniques realized in diffusion cells together with isothermal titration calorimetry capable of elucidating the nature of ongoing reactions from a thermodynamic point of view. The experiments were performed with a humic acid isolated by standard isolation procedure from Leonardite (1S104H) purchased from the International Society for Humic Substances, with humic acids isolated from lignite as well as modal chernozem. The aim of the submited diploma thesis is to assess the influence of carboxyl functional groups in the structure of humic acids to interactions with Septonex. For this reason, said samples of humic acids have been modified by selective methylation of their carboxyl functional groups, which can no longer participate in interactions with ionic substances. Results from diffusion cells and isothermal titration calorimetry confirmed the assumption that Septonex interacted with all types of unmodified humic acids more than with their methylated derivatives. Despite the available literature, it was surprising that the differences in the interaction of humic acids with Septonex were not diametrically different when comparing unmodified humic acids with their methylated derivatives. The extent of these interactions was assessed through the apparent equilibrium constant Kapp determined in the diffusion (dialysis) experiments and from the course of enthalpy curves from isothermal titration calorimetry. After the experiments and their evaluation, it can be concluded that humic acids and Septonex in their interactions, due to their structures, probably apply not only electrostatic interactions, especially through available carboxyl functional groups of humic acids and positively charged hydrophilic parts of Septonex molecules, but also a significant role have a hydrophobic effect, hydrogen bonds and Van der Waals forces.
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