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Microrheology in systems of polymeric colloids
Bjalončíková, Petra ; Sedláček, Petr (referee) ; Venerová, Tereza (advisor)
My bachelor’s thesis was aimed to deal with evaluation of microrheology method in the research of polymer colloids. Used polymers were poly(sodium 4-styrenesulfonate) and sodium carboxymethyl celullose. For measuring of microrheology were used particles with different radius (1 m and 4 m). The results obtained with passive microrheology were compared with results obtained with clasical rheology. It was found, that both substances have viscous charakter. The values of polymer viscosity were similar for dilute solutions in both methods, but for concentrated solutions deviations were found. The reason are polymer nets, which do not allow sufficient movement of particles in concentrated solutions.
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Reactivity of modified humic gels
Lang, David ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis the adsorption of copper ions on humic gels was studied. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then by precipitating with hydrochloric acid or magnesium chloride. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, Thus the extracted amounts are bigger.
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Study on sorption of inorganic nutrients on lignite
Vahala, Jan ; Klučáková, Martina (referee) ; Sedláček, Petr (advisor)
Although lignit represents a valuable chemical substrate, it has been utilized mostly as a fuel in energetic industry. This application is not cost-effective at all and provides a negative ecological impact. Therefore, this bachelor thesis focuses on sorption properties of lignite utilizable in its alternative, mostly agricultural applications. Experimental part of the work deals with sorption and desorption of model inorganic nutrients (nitrates and phosphates as main components of standard inorganic fertilizers). Results of the experiments provides closer view on an application potential of lignite as a carrier of these nutrients or as an organic supplement to traditional NPK agricultural fertilizers.
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Optimalization of experimental method for study on penetration of humic acids into leaves.
Smilková, Marcela ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis is focused on the study of penetration of humic substances trough the plant cuticle. The main objective of the thesis aimed at a literature search on foliar fertilization and transport of substances in the plant leaves. According to the literature search, experimental technique was suggested and tested in order to study penetration of humic substances through the leaf cuticle. The method consists of observation of diffusion transport of humic acids between two inert agarose gels separated by the plant cuticle. Cuticles were prepared by the means of three different isolation procedures.
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Diffusion processes in modified humic gels
Grunt, Jakub ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis presents a study on diffusion of cupric ions in humic acid gels. A total of four types of samples were made during a modified preparation of gels. Humic acids were dissolved either in sodium hydroxide or in the solution of sodium triphosphate. Subsequently, hydrochloric acid and magnesium chlorid were used for "precipitation" of the gels. Gained samples differed particularly in the nature of interactions forming their gel structures. All the samples were subjected to diffusion experiments. Two different methods – constant-source diffusion and immediate planar source diffusion – were used to assign the diffusion coefficients. Both these methods were based on monitoring how the diffusion profiles of cupric ions in gels develop in time and on assigning the overall diffusion flow. The aim of the thesis was to assess the impact of gel preparation procedure and resultant structure on diffusion coefficients of cupric ions and their transport attributes in gels in general. Two different methods of diffusion inquiry were chosen particularly to assess the impact of cupric ion concentration on the diffusion coefficient.
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Development of non-energy use of lignite
Macháčková, Mirka ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis deals with the study of non-energetic use of lignite. The use as a sorbent is one of many possibilities. Sorption of chloride and sodium ions was carried out on natural lignite from the South Moravian, lignite washed with deionized water and lignite enriched with calcium ions. The experiments were realized monitoring pH, electrical conductivity, amounts of sodium and chloride ions in the prepared samples. Chemical oxygen demand was determined in the extract of lignite. This measurement was carried out in accordance with norm ČSN 83 0540-8 Chemical and physical analysis of waste water: Determination of dichromate oxidability. For use in agriculture were investigating the possibility of preparation of humic hydrocolloids by high speed dispergator and planetary mill. The ideal ratio of lignite and water was determined. The liquid and solid humic hydrocolloids were prepared by mechanochemical activation the lignite. These were characterized - particle size, UV-VIS spectroscopy of prepared extracts and sedimentation.
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Preparation of humic hydrogels with incorporated metal ions
Palková, Michaela ; Kislinger, Jiří (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis deals with the study of interaction of cupric ions as a model heavy metal with humic-substances in a hydrogel form. Main objective of the work was to suggest and optimize methods of preparing hydrogel forms of humic acids with the cupric ions and to study the influence of the ions on the properties of the prepared hydrogels while using analytical and physic-chemical methods. The investigated parameters for the characterization of prepared hydrogels were inner pH of the hydrogels and the pH of the solution at different stages of preparation, the quantity of copper ions in the hydrogels, the possibility of extraction and characterization of the structure of resulting hydrogel forms. The experimental results have conformed the expected influence of metal contact in the hydrogel forms of humic substances
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Preparation and characterization of novel application forms of humic substances in combination with water sorbents
Nováčková, Táňa ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis discusses an applicability of hydrogel forms-based composite materials of humic acids and commercial water sorbent. According to the literature review, methods of incorporation of humic acids into commercial sorbents of water under various conditions and the resulting materials were subsequently characterized. In the characterization, major attention was paid to the determination of the water content and the swelling characteristics. Preparation of the composite materials was directed to use their sorption abilities and ability to control the release of humic substances in agriculture.
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Preparation and characterization of novel materials based on combination of humic acids and chitosan
Kozelková, Aneta ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with an application potential of newly developed forms of mixed composites of humic acids, chitosan and commercial granulated inorganic fertilizer.. The main aim was to test some preparation methods selected on the basis of literature search. The experimental part focused on characterization of prepared composite materials, the main attention was paid to the sorption of water, release of humic acid and mineral nutrients into solution, and last but not least, on the mechanical properties of resulting materials. The motivation of this work comes from the potential of agricultural and environmental applications of such composites resulting in a renewal of previously exhausted organic content of soils and consequent interruption of substantial soil degradation.
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Bond strength of metal ions in humic gels
Potočková, Jana ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This thesis deals with the study of bond strength of Cu2+ ions in humic gels. Two methods of extraction were used during the study, sequential and fractional extractions. During the fractional extraction leaching of copper proceeds in single agents, whereas during the sequential extraction leaching proceeds gradually in all extraction agents. Destilled water, 1M MgCl2, 1M HCl and 0,025M NH4EDTA were applied like extraction reagents. Amounts of Cu2+ ions in leaches after extraction were measured by UV-VIS spectrometry. By using extractions was obtained the fractionation of Cu2+ ions according to bond strength in humic gel.
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