|
|
Influence of content of organic matter and calcium on immobilization of pharmaceuticals in soil
Kotradyová, Viktória ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This thesis aimed to highlight the problem of antibiotics and their presence in nature, particularly tetracycline. High global consumption, limited metabolism in the body and incomplete degradation in wastewater treatment plants represent the reasons why pharmaceuticals have been found in the environment. Their presence might have a negative impact on the natural ecosystem, including humans. Therefore, addressing their behaviour and finding solutions for their removal from nature seems important. The soil itself has a self-cleaning capacity, which may immobilise these pollutants into organic structures to prevent their subsequent migration. The presence of inorganic cations in soil plays an essential role in the sorption process of antibiotics. Calcium ions from the soil with whom the tetracycline forms chelate complexes, should be also taken into account. Regarding the practical part, tetracycline interactions with soil systems were studied in both sorption and desorption experiments. Four soils with different amounts of organic matter and calcium have been examined. Tetracycline was extensively adsorbed to all four soils. Desorption processes showed low efficiency and refer to stable adsorption onto soil. The experimental data were fitted by Freundlich and Langmuir isotherms, where the second mentioned is suitable for three of the four soils. Subsequently, sorption and desorption experiments were conducted in four different pH buffers (3, 5, 7 and 10). The effect of pH on sorption was not significant, however during desorption at lower pH higher desorbed levels of tetracycline were observed. Photodegradation of tetracycline in solution was investigated to determine the rate of degradation of tetracycline on light, where the results indicated that the concentration decreased by 22 % after 29 days compared to the applied concentration. Quantitative analysis was carried out using UV-VIS spectroscopy and liquid chromatography. In addition, the soil spectra of the FTIR were measured to obtain information on the sorption mechanism
|
|
|
Determination of the penetration of the active substances
Blažejová, Natálie ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This thesis is focused on the simulation of penetration of active ingredients used in cosmetic products. A theoretical part was written which focused on the basic characteristics of active ingredients used in the cosmetic and pharmaceutical industry. A method for the determination of these actives by means of Franz diffusion cells, which are used to determine the concentration of actives passed through the skin using different skin models, was described. The experimental part focused on the simulation of the penetration of two active ingredients, bisabolol and ectoine, which were provided by the cosmetic company Nobilis Tilia for this work. The amount of these actives was determined through Franz diffusion cells, using a synthetic Strat-M® membrane and a membrane prepared from pig ear skin. Furthermore, the tape-stripping method was used to determine the active substance in the skin layers. All samples were then analysed by UV-VIS spectrometry and liquid chromatography.
|
|
|
Transport of pharmaceuticals in model hydrogels
Horváth, Michal ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
This thesis was devoted to the transport properties of diclofenac in model hydrogels. Gels were prepared from agarose and some were enriched with IHSS Elliott Soil humic acid. The addition of humic acid to the hydrogel should mimic the soil environment. And it was the soil environment that was chosen to observe the transport and transfer of diclofenac. Diffusion was observed in diffusion cells, where one part contained diclofenac solution and the other MQ water. And there was a hydrogel between the cells. Samples were taken from both cells and measured spectrophotometrically at different time intervals until equilibrium was established. These measurements were finally used to describe the movement of diclofenac in the hydrogels.
|
|
|
Migration of pharmaceuticals in soil systems
Janebová, Denisa ; Pekař, Miloslav (referee) ; Klučáková, Martina (advisor)
The increasing use of drugs leads to their frequent occurrence in the environment, which poses a risk not only because it can lead to the proliferation of antibiotic-resistant bacterial strains, but also because it can threaten human health. Therefore, this work focuses on the issue of the occurrence and behaviour of two antibiotics in soil, specifically tetracycline and sulfamethoxazole. Due to the presence of soil organic matter, it is believed that the soil can partially prevent the spread of drugs that enter the environment. The diploma thesis involved conducting diffusion experiments in soil columns under real conditions to determine the effective diffusion coefficients of tetracycline and sulfamethoxazole in three extraction agents. Sorption and desorption processes were also conducted in the individual layers of the soil column. The concentrations of the leachates were measured using UVVis spectrometry and liquid chromatography, while FTIR spectrometry was used to confirm the presence of the bound drug in the soil column.
|
|
|
Interactions of pharmaceuticals with humic substances in model hydrogels
Fleischhackerová, Claudia ; Krouská, Jitka (referee) ; Klučáková, Martina (advisor)
This bachelor's thesis is focused on the study of drug diffusion in humic acid hydrogels. The instantaneous surface source diffusion method was used for this study. This method was based on the observation of emerging diffusion profiles of drugs which diffused in the humic gel at certain time intervals. Then, this method was used to determine the diffusion coefficients of the drugs used in the gels. The main aim of the experimental part was to study the influence of the interaction of drugs with humic acids that diffused through the humic gel. Two drugs were used as a diffusing medium, i.e. ibuprofen and tetracycline. They are pharmaceuticals, the consumption has been increasing in humans and animals in recent years, that's why they are often detected in the environment. The concentration profile of these drugs in humic acid hydrogels was determined by UV–VIS spectrometry.
|
|
|
Application of superabsorbents in soil and its influence on plant growth
Závodská, Petra ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This thesis is focused on description of superabsorbents with controlled released of nutrients, specifically macronutrients nitrogen, phosphorus and kalium. Superabsorbents are polymers, mostly acrylic acid polymers, that can absorb huge amount of water without dissolving in it. In its structure they can hold water and thanks to this they are very perspective materials for agricultural usage. Experimental part was focused on growing corn with use of superabsorbents and control samples without use of superabsorbents. Plants were growth for 3 time periods, specifically 46, 60 and 74 days. During the experiments, plats were growth without water stress and in controlled conditions in growing box under UV lamp that simulated day and night by turning on and off after 12 hours. At the end, an image analysis was performed in HARFA program, from which we got information about branching of the roots. Results were supplemented by soil and plants analysis.
|
|
|
Fractional composition of metal ions in humic gels
Potočková, Jana ; Gregorová, Eva (referee) ; Klučáková, Martina (advisor)
This thesis deals with bond strength of metal ions in humic gels. Several samples of humic acids were studied to consider influence of samples isolation process and their consequent characteristics on bond strength of metal ions in their complexes. Some functional groups was blocked by methylation at some samples. Amount of active functional groups in individual samples was determined by standard titration methods. Metal ions bound in humic complexes were divided into several fractions by extraction with different reagents (distilled water, 1M MgCl2, 1M HCl and 0,025M NH4EDTA). Two extraction methods were used: sequential and fractional. During the fractional extraction leaching of metal ions always proceeds in single agents from original komplex, whereas during the sequential extraction leaching proceeds gradually in all extraction agents in order according to rising afinity of agents, i.e. bond strength of metal ions in samples. Amount of metal ions in leaches after extractions was analysed by UV-VIS spektrometry.
|
|
|
Study on relaxation properties of hydrogels using rheological techniques
Lorenc, Pavel ; Klučáková, Martina (referee) ; Smilek, Jiří (advisor)
Submitted bachelor’s thesis deals with the study of relaxation and time stress of viscoelastic substances (hydrogels) using selected rheological techniques, especially with regard to oscillation tests. Hydrogels with different types of crosslinking were prepared and their properties were compared during the measurement. Agarose hydrogels (physically), alginate hydrogels (physicochemically), polyvinyl alcohol hydrogels (chemically) and hyaluronic acid hydrogels (ionically). In this bachelor's thesis, methods for measuring the relaxation properties of these hydrogels using a rheometer were designed and subsequently applied. We examined the relaxation properties of hydrogels using time-dependent tests that examined changes in amplitude over time. We performed a test that had 3 intervals, in which we monitored the response of hydrogels to the changes by changing the amplitudes of deformation with time. The relaxation properties of these hydrogels were studied, which showed significant differences in the behavior of hydrogels in measurements.By these methods, it was found that the structure of hydrogels and concentrations have an influence on relaxation. From the measured results, it was shown that the best relaxing properties have chemically crosslinked polyvinyl alcohol hydrogel, the lowest ability to relax was shown by physico-chemically crosslinked alginate hydrogel.The results from the measured data were finally compared, assessed and commented on the differences between the individual hydrogels.
|
|
|
Sorption ability of humic acids
Pokorná, Markéta ; Havelcová, Martina (referee) ; Klučáková, Martina (advisor)
The Diploma thesis deals with humic acids and their ability to adsorb metal ions on their surface. Humic acids are aromatic polycyclic compounds which contain carboxylic and fenolic functional groups on their sidechains. Thanks to these functional groups humic acids can form complexes with metal ions of different stability and assist the partial immobilization of pollutants in the nature. In this thesis, the sorption of Pb2+ and Zn2+ ions on humic acids was studied by relatively new electroanalytic method called galvanostatic stripping chronopotentiometry. Experimental data were described by Freundlich and Langmuir isotherms. The results show that the amount of examined metal ions increases with their increasing concentration. Furthermore it was determined that Pb2+ ions are adsorbed better on humic acids than Zn2+ ions. Both metals are adsorbed better from solution containing only one metal ion than in presence of four metals at the same time (Cd, Cu, Zn and Pb) where the sorption of these metals is not influenced by the presence of other metals.
|
|
|
Characterization of hydrogels based on photocross-linked derivative of hyaluronan
Hekrlová, Veronika ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This bachelor thesis focuses on characterization of hydrogels based on photocross-linked Tyramine-modified hyaluronan (HA-Tyr). In the first part of the work, swelling of gels in saline and porcine plasma was examined, in which the hydrogels swell significantly less. The second part of the thesis is focused on rheology. First, dependence of the apparent viscosity of precursor solutions on shear rate was tested. The apparent viscosity increases with the concentration of derivative and Mw. This trend can also be observed when measuring viscoelastic properties (the elastic modulus) in oscillation mode (strain sweep test). The elastic modulus can also be affected by using a higher concentration of the photoinitiator riboflavin (RF), higher radiation intensity or by longer exposure times, although the material can be degraded. The work also includes an ATP bioluminescence method cytotoxicity test, which proved that the methods used are safe for in situ application.
|
guest ::
RSS feed.