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Involvement of vibrational spectroscopy in the study on interactions of natural organic matter with model environmental pollutants.
Stehlíková, Kristína ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The main objective of this diploma thesis was to verify the potential of using advanced infrared spectra processing techniques – specifically the principal component analysis (PCA) – in order to monitor the interaction of natural organic matter with organic pollutants. Natural organic matter was represented by standard IHSS Leonardite humic acid, while the aromatic dyes methylene blue and Rhodamine 6G and the aliphatic substance Septonex were chosen as representatives of organic ions. Their interactions were monitored using Fourier-transform infrared spectroscopy, the use of which for this purpose was verified in my bachelor's thesis. Principal component analysis was finally applied to the obtained infrared spectra of the formed complexes and prepared blank samples, which helped to reveal spectral changes at first glance unrecognizable in the spectra themselves. It was found out that the most likely mechanism of humic acid interaction with aromatic pollutants is a - interaction, while the electrostatic nature of the interaction is assumed for the binding of aliphatic substances.
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Study of plasma activated water application on the soil enzyme activity
Lungová, Tereza ; Enev, Vojtěch (referee) ; Krčma, František (advisor)
The aim of this thesis was the characterization of plasma activated water (PAW) prepared by dielectric barrier discharge under atmospheric pressure and the evaluation of its effect on soil enzymatic activity in a black soil sample, which contains chemically active substances so-called long life species. For this purpose, the pot experiment was chosen based on literature research. Dehydrogenase (DHA) enzyme activity was investigated to determine total soil microbial activity in soil samples watered with plasma activated water with different activation times. Dehydrogenase belongs to the group of oxidoreductases and its activity is a suitable indicator of active biological activity in the soil. In this work, the values of dehydrogenase activity were determined for PAW with 2 minute treatment 2,3 g/gh, for PAW with 5 minutes treatment 2,7 g/gh and for PAW treated with plasma discharge for 10 minutes 3,5 g/gh. In the comparative sample, which was watered with distilled water, the value of dehydrogenase activity was determined to be 2,5 g/gh. Based on the overall analysis, it was found that there is no negative influence on the enzymatic activity in the soil despite the wide range of confirmation of the antimicrobial effects of PAW.
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Characterization of microfludic chips
Vejrosta, Jakub ; Enev, Vojtěch (referee) ; Venerová, Tereza (advisor)
Nowadays, when we are moving to smaller and smaller scales, microfluidics is being used, which helps us to move from fluid devices to the dimensions of microfluidics, which may have a great application in the future. This work deals with the correct preparation and production of a microfluidic chip. Which consist of two parts. One part is the polydimethylsiloxane (PDMS) part of the chip, and the other is the coverslip. In this work, the production process of this chip is improved. The functionality of these chips and the time dependence of the age of the chip and the polydimethylsiloxane from which the chips are made were tested using fluorescence microscopy.
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Transport of pharmaceuticals in soil systems
Janebová, Denisa ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
Drugs have a negative effect on nature. If they do not degrade in wastewater treatment plants, they can contaminate lakes, rivers and even drinking water. However, the soil contains soil organic matter, which has chelating properties and can prevent the migration of the drug. The aim of this bachelor thesis was to map the transport of the selected drug in the soil column and try to determine its diffusivity. Sulfapyridine was chosen for transport. Sulfapyridine belongs to a group of sulfonamide antibiotics that are often detected in the environment. It is mainly used in veterinary medicine to treat various infections. The partial goal was to describe the basic properties of the soil depending on the depth of the soil layer. The drug concentration profile in the soil column was determined by UVVIS spectrometry in soil extracts. The following reagents were used for leaching: distilled water, as a pure solvent without the presence of other substances, tap water as a model reagent replacing the soil solution and magnesium chloride solution, which is used for soil extracts of freely moving and ionically bound substances in the soil.
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Use of Hofmeister series of ions for fractionation of soil humic acids
Kebabová, Mona ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
The bachelor thesis deals with the study of the structure and behaviour of humic acids (HA) in the presence of salts of the Hofmeister series of ions. Haplic Luvisol and sodium humate extracted from it were characterized by elemental analysis (EA) and thermogravimetric analysis (TGA) to determine the percentage of elements and ash. Fourier Transform Infrared Spectroscopy (FT-IR) was used to determine the functional groups in the sample. UV-VIS was used to investigate the effect of the Hofmeister salts. From its results were calculated the absorption coefficients EET/EBZ, E2/E3, E2/E4 and E2/E6, and the specific absorbance values SUVA254 and SUVA280. Other methods like Dynamic Light Scattering (DLS) and fluorescence spectroscopy were used to better understand HA's structure. The main goal of this bachelor thesis was to find a simple experimental method based on which we would be able to study supramolecular associations of HK, which are preferentially linked to the formation of weak intra- and intermolecular interactions in aqueous solutions.
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Bioactive substances for face cream: Determination of stability of face cream incorporated with goat's milk
Dostálová, Tereza ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
The aim of this bachelor thesis is a stability trial of a skin cream incorporated with goat milk lyophilizates prepared in usual laboratory conditions. Firstly, the goat milk was denatured, to be further analysed via FTIR, elemental analysis and thermogravimetry. To compare the denaturation effect, measurements with native goat milk sample were performed as well. Next, an emulsion was prepared. First stability tests were performed using analytical centrifuge and the cream preparation procedure and component ratio was optimized. Stability trials were carried out at specified time intervals. Rheological properties – especially yield stress values and structure strength, determined by linear viscoelastic region and complex modulus – thermal endurance measured via differential scanning calorimetry and visual validation via optical microscopy and sample observation were tested and performed. Skin cream stability of sample stored at laboratory temperature was demonstrated, showing moderate sings of structure destabilisation. Product suitability for dry skin was proved by sensory analysis. The skin feeling was pleasant, and the cream moisturized the surface area, that it was applied to, according to evaluators. Visually, the emulsion appeared to maintain its properties during the experiment time range, it did not undergo a complete degradation of separation into two original phases, nor it was degraded, for example by mold.
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Utilization of physico-chemical and spectroscopical methods in study on microbial extremofiles
Dobešová, Kateřina ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is the determination od polyhydroxyalkanoates in the cells of extremophille bacterie, preformed by several methods. The chosen bacterium was Schlegelella thermodepolymerans DSM 15 344 Thermogravimetric analysis, infrared spectroscopy with Fourier transformation, and Raman spectroscopy were used in this thesis. The TGA method was used for the determination of extracellular and intracellular water in samples. The FTIR method was used in order to observe the amount od PHA, but aslo to observe the physical properties of the polymer in the sample, specifically to determine either amorphous or crystalline featuers of this polymer. Raman spectroscopy was used in oder to confirm the presence of PHA in the samples. All results e´were compared eith the results accomplished by gas chromatografy.
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Preparation and characterization of magnetic nanoparticles modified by surfactants
Solnička, Ondřej ; Másilko, Jiří (referee) ; Enev, Vojtěch (advisor)
Theme of this bachelors thesis was preparation and characterization of iron(II, III) oxide nanoparticles. Those nanoparticles were modified by surfactants. The surfactants which were used for modifiation were CTAB, TTAB and Septonex. Prepared and modified nanoparticles were taken for characterization by using methods of elemental analysis, thermogravimetry, dynamic light scattering and transmission electron microscopy (TEM). Results from each measurement shows that nanoparticles modified by CTAB had on average 85.9 nm in diameter, TTAB size was on average 108.3 nm and the last nanoparticles with Septonex had 246.6 nm in diameter on average. Prepared modified nanoparticles except the Septonex ones were stable enough to not aggregate. Septonex modified nanoparticles had greater tendenty to aggregate.
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Physicochemical characterization of soil humic substances isolated from Fluvisol
Šátková, Eliška ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis is focused on the physicochemical characterization of humic substances that are isolated from fluvisol. Humic substances were isolated by a standard procedure according to the International Humic Substances Society (IHSS). Extracted humic substances were further characterized by thermal and spectrometric methods, which include elemental (EA) and thermogravimetric analysis (TGA), UV/Vis, and FTIR spectrometry. Potentiometric titration was an important contribution to characterization. Based on the obtained data obtained from the EA and TGA, the content of biogenic elements and the thermal stability of HL were determined. Absorption coefficients were calculated from the measured UV/Vis spectra to determine the aromaticity and average molecular weight of HL. The HL functional groups were determined by FTIR spectra, and the acidity was determined by potentiometric titrations. The obtained results very well characterized the individual humic substances isolated from fluvisol.
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Use of thin layer chromatography for fractionation of humic substances isolated from oxyhumolite
Hegrová, Nela ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
The main goal of this thesis was to optimize the fractionation of humic substances (HS) using the method of Thin-layer chromatography, so that it can be used for physico-chemical characterization of the obtained individual organic fractions. Due to the high content of HS in the natural oxyhumolite matrix this oxidized brown coal was selected as a source of these biocolloid compounds which were isolated according to the international IHSS procedure. The sample of native oxyhumolite and oxyhumolite after extraction was characterized by thermal techniques such as thermogravimetric (TGA) and elemental analysis (EA). The above-mentioned oxyhumolite samples were further analyzed by Fourier transform infrared spectroscopy, mainly for deeper understanding of their structure in terms of an organic matrix containing HS. Characterization of isolated HSs was performed by the following thermochemical and spectrometric techniques, elemental analysis, thermogravimetry, ultraviolet and visible electromagnetic absorption (UV/Vis) molecular spectroscopy, Fourier transform infrared spectroscopy and steady-state fluorescence spectroscopy. Molecular absorption spectroscopy (UV/Vis) and steady-state fluorescence spectroscopy were used for physicochemical characterization of individual organic fractions.
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