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Transport properties of humic gels
Sárová, Michaela ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
This bachelor’s thesis is focused on study of transport properties of humic gels. For research of these properties was used diffusion method of organic dyes in diffusion cells which is based on spectrophotometric monitoring of concentration changes depending on time. Dyes used in the experiment were specifically methylene blue and rhodamine 6G and diffusion experiments were performed on an agarose hydrogel without the addition of humic acid, with the addition of unmethylated humic acid and then with the addition of methylated humic acid. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. It has been found that the presence of humic acid in agarose hydrogel greatly influences the transport of dyes.
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Preparation of humic hydrogels for appliaction in cosmetics
Pavlicová, Renata ; Mravec, Filip (referee) ; Sedláček, Petr (advisor)
This bachelor´s thesis is focused on the preparation and characterization of hydrogels containing humic substances and assessment of their potential usefulness in cosmetic practice. Main objective of the work was to develop a literature review focusing on the potential use of humic substances in the cosmetics and pharmaceutical industries. Furthermore, the aim was to prepare model hydrogels addition of soluble humic substances in traditional cosmetic compositions and their characterization by basic methods of analysis parameters. The main investigated parameters were consistency resulting gels (assessed subjectively and subsequently by rheology), their internal pH and dry matter. The experimental results showed that incorporation of humic substances into hydrogels resulting gels acceptable characteristics for further use in cosmetic applications.
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Influence of pH and ionic strength on barrier abilities of humic substances
Přítulová, Marie ; Kratochvílová, Romana (referee) ; Klučáková, Martina (advisor)
The main aim of this bachelor thesis is the study of humic acids and their barrier properties. The reactivity of humic acids was studied by simple laboratory diffusion techniques in plastic diffusion cells. This thesis is mainly focused on the through-diffusion processes in hydrogel media. Hydrogel media were based on the thermoreversible polysaccharide (agarose) with or without addition of humic acids. The rate of reactivity of humic acids was compared by the interactions with organic cationic dye – methylene blue. The influence of ionic strength and pH was tested as well.
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Using diffusion techniques in the study of hydrogels
Holubová, Anna ; Žitňan, Michal (referee) ; Mravec, Filip (advisor)
Properties of colloidal systems, especially hydrogels, were studied using the method of fluorescence correlation spectroscopy (FCS). Hydrogels were prepared based on hyaluronan and cationic surfactant CTAB interactions. The proposed hydrophilic fluorescent probe, suitable for the study of phase-separated hydrogels in polymer-surfactant systems, was chosen ATTO 488 due to the suppression of triplet state. As a hydrophobic probe was chosen Nile Red. Individually were examined micellar systems of 10 mM CTAB and 0,5% sodium hyaluronate in water and 0,15 M NaCl in different concentrations of selected fluorescent probes. Subsequently the hydrogel systems were studied. The results showed that the measurement of hydrogels by this method is realizable. Short lifetimes were created by a complex probe and CTAB causing quenching and low levels of diffusion coefficients characterize the viscous environment of study system.
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Study on Sol-gel Process of Agarose by Classical Rheology and Dynamic Light Scattering
Krňávková, Šárka ; Hnyluchová, Zuzana (referee) ; Smilek, Jiří (advisor)
The main aim of the bachelor thesis was characterization of hydrogels from rheological point of view and by dynamic light scattering. Rheological part of research relates with the determination of the influence of temperature on mechanical properties, gelation temperature and temperature of solidification as well as the effect of aging on mechanical properties of hydrogel. The influence of the particle size on diffusion coefficient was investigated by scattering techniques. The positive correlation between the data obtained by both types of measurement and the potencial usage of dynamic light scattering method for the characterization of hydrogels was discussed as well.
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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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Rheology of humic gel
Smilek, Jiří ; Gregorová, Eva (referee) ; Klučáková, Martina (advisor)
The main aim of the bachelor thesis was to test several modifications of humic hydrogels’ preparation method and to discuss their effects on mainly viscoelastic properties of resulting materials. Main conditions, tested in the experimental part, were presence of acidic impurities from the gelation step in the gel and an addition of cations with a higher valence during or after the preparation step. The most important evaluated parameters of the materials were inner pH, solid content and mainly basic viscoelastic characteristics.
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