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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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Interaction in ionic surfactant/non-ionic surfactant/polyelectrolyte system
Pihíková, Dominika ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
The interactions in an ionic surfactant/non-ionic surfactant/polyelectrolyte system have been studied in this bachelor thesis. The value of critical micelle concentration of cationic didecyldimethylammonium chloride (DDAC) has been determined in three different mediums by fluorescence spectroscopy using Pyrene, Perylene and Nile red as probes. The CMC value of non-ionic octylphenol ethoxylate (Triton X-100) has been determined using Pyrene and Perylene as probes. The aggregation behavior of non-ionic and ionic surfactant with addition of polyelectrolyte poly(sodium4-styrensulfonate) (PSS) and native hyaluronan in aqueous solution has been investigated using Pyrene as a probe. Aggregation number in system of ionic/non-ionic surfactant has been determined by a fluorescence quenching with cetylpyridium (CPC) as a quencher and Pyrene as a fluorescence probe. Interactions in ionic surfactant/non-ionic surfactant/polyelectrolyte system were observed. This result was proved by double sigmoid Boltzman´s type curve. The addition of low molecular as well as high molecular hyaluronan had no significant effect on CMC value of the system.
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