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Isolation and fractionation methods for determination of humic substances content in South Moravian lignite
Černý, Pavol ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis focuses on isolation and fractionation of humic substances (HS) from the natural matrix of lignite, which comes from southern Moravia from the mine Mír Mikulčice. In the theoretical part, it informs the reader about the issue, starting with information about lignite and HS. In this work, the standard procedure of isolation and fractionation of HS was used as according to the International Humic Substances Society (IHSS). The content of HS in the natural matrix of lignite was determined, and then isolated HS were subjected to physicochemical characterization – elemental analysis (EA), thermogravimetric analysis (TGA), UV/Vis spectrometry, infrared spectrometry with Fourier transformation (FTIR) and the acidity of humic acids (HA) was determined by potentiometric titration. EA was used to detemine the content of biogenic elements, moisture and ash content were determined by TGA. By using FTIR, various functional groups and building blocks that are present in supramolecules of HS were indentified and absorption coefficients EET/EBT, E2/E4, E2/E3 a E4/E6 were determined by UV/Vis spectrometry. Results represent good characterization of HS isolated from lignite and are in agreement with scientific literature.
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Distribution of the Organic Matter in a Sample of Biochar
Novotný, Maximilián ; Enev, Vojtěch (referee) ; Kalina, Michal (advisor)
This bachelor’s thesis is focused on characterization of the content and distribution of organic matter in a sample of biochar. For these purposes, the organic matter from a biochar sample was isolated using two procedures, specifically sequential chemical fractionation, and alkali extraction. Prepared samples were characterized by elemental analysis and thermogravimetry. Analysis results showed that sequential chemical fractionation brings higher yields than alkali extraction, moreover, it provides more detailed image of organic matter in biochar thanks to obtained separated fractions according to their linkage to the original biochar matrix. Secondly, studied biochar has a great potential as soil supplement, it contains almost 70 % of organic carbon, whilst isolated amount, which is available represent only small amount, the rest is strongly bound. On the other hand, the study showed that this specific biochar has rigid structure, which brings benefits in the context of using biochar in agriculture in long-term consideration.
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Determination of Paracetamol content in selected drugs using ATR-FTIR spectrometry
Waczulíková, Kristína ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis deals with determination of paracetamol content in selected drugs by ATR-FTIR spectrometry and aims to design and optimize determination of paracetamol in dosage forms by a direct measurement of the sample, called ‘dry way’. Tablets of three drugs containing paracetamol have been studied. Wavelength ranges were determined from the measured FTIR spectra as regions where the absorptions of fillers (microcrystal cellulose, starch and magnesium stearate) were minimal. Absorption bands of paracetamol were selected at the wavenumbers of 1 503 cm-1 and 1 224 cm-1 in order to construct a calibration curve. The contents of paracetamol in the drug tablets were calculated using calibration curves obtained by the method of simple regression analysis. The lowest deviation from the amount of 500 mg paracetamol per tablet as reported by the manufacturer was from the calibration curve for paracetamol with microcrystalline cellulose. The determined amounts of paracetamol per tablet in the selected drugs lied within range 493.5–505.5 mg. These results point to the conclusion that the ATR-FTIR spectrometry method can be used for the quantitative determination of paracetamol in drugs using direct measurement, as deviations from the reference value of 500 mg did not exceed 1.5 % for cellulose and 3.85 % for magnesium stearate and therefore are within acceptable limits for the exploratory study.
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Carbon nanoparticles from South Moravian lignite
Drozdová, Miroslava ; Enev, Vojtěch (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis deals with the issue of isolation of carbon nanoparticles from lignite, which seems to be their cheap source. The aim of this work is to elaborate a research on the use of coal matrices as a source of carbon nanoparticles and also to design and perform further experiments testing the usability of South Moravian lignite. Based on the literature search, a simple mechanochemical procedure was proposed to obtain carbon nanoparticles from lignite. The lignite was mechanically stressed by the ultrasonic disintegrator with simultaneous action of water or hydrogen peroxide. Lignite has been able to isolate particles fluorescing in the blue visible light, but the process will need to be further modified. However, South Moravian lignite could be a source of carbon nanoparticles.
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Influence of pH on Extraction of Matter from Biochar-Soil Complex
Jakubčeková, Kristína ; Enev, Vojtěch (referee) ; Kalina, Michal (advisor)
Biochar is one of the possible solutions to improve the soil fertility, therefore it is necessary to investigate both its composition and the impact on the soil under various conditions. The aim of this bachelor thesis is to focus on the description of the influence of pH on the amount and type of substances (molecules, ions) that are leached from the biochar into the soil and thus consequently influence its properties. As a soil model it was chosen cambisol which is the most widespread soil in the Czech Republic. The selected pH values have been defined in such a way to cover the pH range that is common for various soil types in natural conditions. In the experimental part of this thesis the extracts from the used sample of biochar and soil were characterized first. These characteristics obtained in this way were subsequently compared with the data obtained for the biochar-soil complex extracts that was obtained after a defined period of cultivation of the mixture. For the characterization of extracts the basic physico-chemical methods (pH, conductivity, elemental and thermogravimetric analysis, UV-VIS) and also the analysis of leached ions and molecules by means of ICP/OES, GC-MS were used. Evaluated experimental data show that under the condition of cultivation experiments, the influence of biochar was observed only on the basic physico-chemical characteristics of the soil (mainly pH). On the other hand, there was no significant tendency of the impact of biochar on the representation of selected elements and on the content of organic matter in the soil. Long-term biochar-soil cultivation experiments could be a suitable solution.
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Physicochemical and structural analysis for characterization of native and modified humic acids
Solanský, Pavel ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis is focused on structural and physicochemical characterization of native and methylated humic acid. These samples of humic acids, which were isolated from oxidized brown coal Leonardite, were characterized by thermal and spectrometric methods. The following analytical techniques were selected to determine the structural and physico-chemical changes between native and methylated humic acid: thermogravimetry (TGA), elemental analysis (EA), molecular absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy and last but not least nuclear magnetic resonance (13C NMR). The aim of this bachelor thesis was to find the differences in the structure of selected humic acids and also to verify the suitability of the techniques, which were used to characterize these biocolloid substances.
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Sorption of charged organic compounds on humic acids
Krist, Tomáš ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
Bachelor thesis deals with a sorption properties and physical-chemical characterization of humic acids before and after the adsorption. Sorption experiments with a methylene blue and a rhodamin 6G were performed. Adsorption isotherms were obtain via UV/VIS spectrometry. The Langmuir isotherm was used to evaluate the experimental data. Standard of HA isolated from Leonardite was characterized by an elemental and thermogravimetric analysis, by a Fourier-transform infrared spectroscopy, a surface area analysis and also by a potentiometric titration.
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Isolation and fractionation methods for determination of humic substances content in Leonardite
Lišková, Kateřina ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
The main aim of this thesis was to isolate humic substances (HA and FA) from the natural sample of Leonardite, to characterize their structure and physical and chemical properties. Among other things, the humic acid standard supplied by IHSS, isolated from Leonardite, originally from Dakota, USA, was also studied. The following thermal and spectrometric methods were used to characterize the samples of isolated humic substances: thermogravimetric analysis (TGA), elemental analysis (EA), ultraviolet-visible spectrometry (UV / Vis) and infrared spectrometry with Fourier transformation (FTIR). The atomic ratios were determined from the results of the elemental analysis. Absorption coefficients were calculated from the measured UV/Vis spectra and were used for the physicochemical characterization of these biocolloid compounds. The measured infrared spectra were used to identify the individual functional groups.
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Utilization of Raman spectroscopy and Raman tweezers for analysis and isolation of PHA producing bacteria
Beránková, Barbora ; Enev, Vojtěch (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with the study of the utilization of Raman spectroscopy and Raman tweezers for analysis and isolation of polyhydroxyalkanoates (PHA) producing bacteria. Using gas chromatography with FID detection, we determined the polyhydroxybutyrate (P(3HB)) content of the PHA biomass of bacterial strains Burkholderia cepacia, Halomonas halophila, Cupriavidus necator H16 and its mutant strain Cupriavidus necator H16/PHB-4 and Lactobacillus delbrueckii, which is not a producer of polyhydroxyalkanoates but this bactrea was selected as representative of Gram-positive bacteria. Subsequently, thanks to Raman microspectroscopy, Raman tweezers and FT-IR spectrometer in combination with Raman FT-module, we were able to confirm or disprove the presence of P(3HB) in bacteria. Furthermore, the thesis describes Cupriavidus necator H16, which is a model organism for the production of P(3HB), and his mutant strain Cupriavidus necator H16/PHB-4. The bacterial strain Cupriavidus necator H16 was cultivated in a production mineral medium of various nitrogen contents, while cultivation was also carried out in liquid Nutrient Broth. By this cultivation we were able to reach various P(3HB) content in bacterial biomass, the spectra were subsequently compared with the spectrum of the bacterial strain Cupriavidus necator H16/PHB-4. Raman spectroscopy is well used to characterize the composition of individual bacterial cells, is a fast, versatile, and virtually non-invasive tool for studying cells.
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Interactions of hormones and drugs with soil organic matter
Krajňáková, Soňa ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
This thesis is focused on the problem of interaction of hormones and drugs with a soil organic matter. The most commonly occurring drugs are described, as well as their features, behaviour and possible factors influencing this behaviour. These substances are frequently transported to the soil through a sewage treatment plant, as the cleaning process of wastewater is not effective enough to ensure complete removal of these substances. Once in the soil, the life of organisms in this environment can be negatively influenced. The soil used in experiments was not contaminated with any of these substances as it was used as a matrix for sorption and desorption. Two experiments were conducted using Ibuprofen, where its sorption and desorption on the soil was observed. The intention was to ensure detection of changes which occurred in the concentration of Ibuprofen after concluding these processes. Liquid chromatography method with mass spectrometric detection was used for a final analysis.
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