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Development of New Application Forms of Humic Substances for Agricultural and Environmental application
Kratochvílová, Romana ; Kráčalík, Milan (referee) ; Salaš, Petr (referee) ; Klučáková, Martina (advisor)
The new forms of superabsorbent polymers (SAP) on the base of acrylic acid were developed and studied in this thesis. The SAP are focused on agricultural and environmental applications. While they are applied to the soil, SAP can prevent water losing and they become a reservoir of humidity in case of dry season, moreover in combination with fertiliser they play role of controlled release medium. Eight various samples of SAP were experimentally prepared by networking of partially neutralized acrylic acid. Potassium peroxydisulfate was used as the initiator and N,N–methylenebisacrylamide as the crossing agent. Some of samples contained addition of second monomer of acrylamide. All of them were enriched by fertilisers – natural lignohumate or synthetic NPK or combination of both. The swelling characteristics of prepared samples were investigated in conditions of various ionic strength. The influence of xerogels’ particles size on swelling properties was also observed. The viscoelastic characteristics of hydrogel form of all SAP were determined by using of rotation rheometer. The changing of viscoelastic properties were studied in dependence on time, on freezing and on repeating swelling cycles. On top of that the controlled releasing ability of SAP was tested due to three modelling experiments. The biological activity of all polymer products was tested at the end of the thesis. All samples of SAP were incorporated into the artificial soil and the ability of the water retention in the soil was observed. The growing experiments were running by using of corn plants. The size and the mass of each plant were measured and branching of the root was objectively evaluated by programme Harmonic and Fractal Image Analyzer.
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The behavior of superabsorbent polymers in artificial soils
Männlová, Adriana ; Smilek, Jiří (referee) ; Kratochvílová, Romana (advisor)
This bachelor thesis deals with the study of superabsorbent polymers for environmental and agricultural applications. Generally thessis preparations are to perform the funciton of irrigation ,so that thanks to its unique properties , can absorb water in tha rainy season and keep it arend the root system as long as possible. Superabsorbent polymers can also perform the fiction of fertilizer carries and thus ensure its gradual release. These gel structures were subjected to testing of their swelling in environments with different ionic strenght. Subsequently, in the long term monitored thein ability to trap water in the soil environment model.
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Interactions of metal ions with humic substances
Obručová, Kateřina ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focused on humic substances, especially fulvic and humic acids. It deals with their genesis and subsequent extraction from nature materials. There are described not only physical and chemicals properties, structure of humic and fulvic acid, but also their reactivity. There is also described the method od isothermal titration calorimetry, which was subsequently used to study of interaction fulvic acid with selected metal ions (Cu2+, Ca2+, Mg2+). From the resulting titration data were determined values of reaction enthalpy, which was then compared with model complexes. From the resulting graphs, it was possible to determine when the reaction reached its maximum, the state when all the binding sites were full. Heat values were determined for this condition.
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Experimental study and modelling of the transdermal penetration of active species from gels
Palanová, Veronika ; Opatřilová, Radka (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with design and experimental study of transdermal transport of pharmaceutically active agents from gel matrices, which contain humic substance in its structure. A model absorption membrane was represented by the skin of pig´s earlobes. The study of the release of active substances and Lignohumte was performed due to the vertical diffusion cells. The amount of released humic substance was characterized by UV-VIS method and the amount of released active agent from gel matrix was determined by HPLC-DAD. The most interesting finding of this diploma thesis was that Lignohumate enhances transdermal transport of active agents and supports their release from gel samples to the particular environment.
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Humic substances as transport medium for plant nutrition
Vlková, Markéta ; Solná, Irena (referee) ; Klučáková, Martina (advisor)
This bachelor thesis treats about humic matters and their application in agriculture by means of hydrogels transport medium. It studies progressive releasing of substances, which could be used as more common nutrition for plants, prepared from superabsorbent polymers. Research was implemented in collaboration with industrial partners. The substances are synthetically made of sodium Lignohumate and mixture of industrial fertilizer called NPK. Released substances were characterized by using some methods. First, there were measured qualities, which didn’t specify released compounds, like swelling, conductivity, pH and absorption of hydrogels with different wavelengths. More details came with methods ICP-OES and ion chromatography. Hydrogels which contained both mixtures of matters written up, were studied in water solution for 5 weeks and every week all characterization were measured. From the results we can see that both of the mixtures decrease ability of hydrogel’s swelling, mainly NPK. Measuring of absorption showed that the most of the substances released from sodium Lignohumate were from hydrogels without NPK. By other measuring, we noticed realizing of potassium and phosphorus elements. The most of them were from hydrogels containing NPK. By measuring ion chromatography, we found chloride, phosphoric, sulfuric and nitric ions in solution.
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The Study of Aggregation of Humic Acids in Different Xenobiotic Environments
Hronová, Aneta ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
Theme of the presented bachelor thesis is the study of the aggregation behavior of the humic acids (HA) in the environment of extraneous substances. As extraneous substances, three cationic surfactants were selected (CTAB, TTAB and Septonex). In the experimental part of the thesis, the humic acids were characterized in detail using different methods (elemental analysis, ash content determination, titration acidity determination). The experimental part of the thesis is dealing with the structure of created HA-surfactant systems. These systems were characterized using the results of the elemental analysis and FT-IR spectroscopy. The key part of the experimental part of the study is represented by the selection of proper methods and by determination of the critical aggregation concentration of the humic acids in the surfactant environment. For these purposes, two key methods were selected in the frame of the presented bachelor thesis: isothermal titration calorimetry and dynamic light scattering. The first method is sensitive owing to the energetic fluctuations, in the case of the dynamic light scattering we are able to detect well the changes in the particle size caused by mutual interactions of particular substances in the system.
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Humic substances as active or auxiliary pharmaceutical component
Blahuš, Petr ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
This thesis examines the effect of the potassium lignohumate on the transfer speeds of analgesic drugs through the synthetic Strat-M® membrane. In order to examine the transfer of these substances, vertical diffusion cells were used and the final samples were analysed using UV-VIS spectrometer and HLPC. The intention of this thesis was to optimise the process of preparing diffusion cells, to compare the transfer speeds of pure active substances and active substances with the potassium lignohumate, and to compare the permeability of Strat-M® membranes, by using pig skin membranes which were used in the previous study that this thesis continues from. The primary discovery was that the lignohumate slowed down the transfer of active substances through the membrane.
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Hydrogels made of biopolymers for agricultural and environmental applications
Ondruch, Pavel ; Záhora, Jaroslav (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on development and characterization of hydrogel materials for agricultural use. In the experimental section, different methods of preparing these materials were designed and optimized according to previous literature review. In the characterization of resulting materials, the main attention was paid to the kinetics of swelling, to the solubility, the leaching of nitrate and of humic compounds. Thermogravimetric analysis represented another important characterization technique, which provided information about the content and form of water bound in the material. The development of the material aimed mainly at an agricultural application providing the delivery of nutrients to soil and regulation of water content in soil.
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Complex physicochemical analysis of natural medicinal water
Machátová, Nikol ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis is focused on the study of the content humic substances in natural medicinal water. Humic substances extracted from this water were characterized by UV-VIS and FTIR spectroscopy, hereafter microbiological tests were performed. The main aim was determine the content HS using the norm ČSN 75 7536 and the calibration curves of standard fulvic acid Suwannee River. Another part of this bachelor thesis was focused on spectrometric characterization HS after different degree of purification. Humic substances were characterized by absorption coefficients and FTIR spectroscopy.
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Conformation and molecular organization of humic acids in aqueous solutions
Věžníková, Kateřina ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
This diploma thesis deals with the conformation and molecular organization of humic acids in aqueous solutions. Humic substances have heterogeneous and polydisperse nature, therefore their secondary chemical structure has not yet been defined properly, neither has their conformational arrangement. The conformation of humic substances in the solutions is mainly stabilized by weak disperse forces, such as Van der Waals, -, CH- interactions and hydrogen bonds. Humic substances in the solutions tend to form aggregates that are held together mostly by the intermolecular hydrophobic interactions. Concentration series of humic acids were prepared in three different mediums of constant ionic strength: NaOH and NaCl (prepared either by neutralization NaOH by HCl or direct dilution by solution of NaCl). Several analytical methods have been used to determine conformation and molecular organization of humic acids: potentiometric determination of pH, direct conductometry, ultraviolet and visible spectroscopy, density measurement, dynamic light scattering, laser Doppler velocimetry and high resolution ultrasound spectrometry. It was confirmed that the conformation and molecular organization of humic acids in aqueous solutions depend not only on pH of medium, but they also depend on chemical nature and concentration with the same pH. Results showed that hydrodynamic diameter of particles is significantly increasing in NaCl medium prepared by neutralization NaOH by HCl, particularly at low concentrations, which corresponds to higher values of zeta potential obtained. Concentration dependencies of ultrasonic velocity and compressibility also indicate the changes in conformation and molecular organization corresponding with results from other methods used.
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