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Spectrometric Methods for Research of Humic Substances
Enev, Vojtěch ; Maršálek, Roman (referee) ; Sýkorová, Ivana (referee) ; Klučáková, Martina (advisor)
The main aim of doctoral thesis is the study on physicochemical properties of humic substances (HS) by modern instrumental techniques. The subject of the study were HS isolated from South Moravian lignite, South Bohemian peat, forest soil Humic Podzol and finally extract from brown sea algae Ascophyllum nodosum. With respect on determination of structure and reactivity of these unique “biocolloids”, standard samples (Leonardite HA, Elliott Soil HS and Pahokee Peat HS) were also studied. These samples were obtained from International Humic Substances Society (IHSS). All mentioned substances were characterized by elemental analysis (EA), molecular absorption spectroscopy in ultraviolet and visible region (UV/Vis), infrared spectroscopy with Fourier transformation (FTIR), nuclear magnetic resonance spectroscopy of carbon isotope 13C (LS 13C NMR), steady-state and time resolved fluorescence spectroscopy. Obtained fluorescence, UV/Vis and 13C NMR spectra were used for calculation of fluorescence and absorption indexes, values of specific absorbance and structural parameters respectively, which were used for fundamental characterization of these “biocolloidal” compounds. Infrared spectroscopy with Fourier transformation was utilized for the identification of functional groups and structural units of HS. Evaluation of infrared spectra is quiet complicated by overlapping of absorption bands especially in fingerprint region. This problem was overcome by Fourier self-deconvolution (FSD). Steady-state fluorescence spectroscopy was used for deeper characterization of HS with respect to origin, structural units, amount of substituents with electron-donor and electron-acceptor effects, content of reactive functional groups, “molecular” heterogeneity, the degree of humification, etc. Parameters of complexation of samples Elliott Soil with heavy metal ions (Cu2+, Pb2+ and Hg2+) were obtained by using modified Stern-Volmer equation. These ions were chosen purposefully, because the interaction of HS with these ions is one of the fundamental criteria for the assessment of the reactivity of HS. Key part of the whole doctoral thesis is time-resolved fluorescence spectroscopy. It is able to determine the origin of emission of HS by method Time-Resolved Area Normalized Emission Spectra (TRANES). The viscosity of micro medium about excited fluorophores of HS was determined by Time-Resolved Emission Spectra (TRES).
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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 compost application on properties of soil humic substances
Enev, Vojtěch ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
The aim of this diploma thesis is to study to the influence of compost addition to soil humic substances extracted from blackland luvicsol. Humic substances extracted from soil and from compost were characterized by titration with potentiometrical and conductival indication, UV-VIS, FT-IR and 3D EEM fluorescential spectroscopy. Compost in amount of 124, 239 and 478 t/ha was applicated and manured into dept of 150 mm at blackland luvicsol. The main aim of thesis was the appraisal of compost influence into fluorescent attributes of soil HS and localization of fluorescent peaks at excitation emission spectrums. Next part of diploma thesis was focused on the study of spectroscopic attributes of soil HS and compost by UV-VIS and infrared spectroscopy with Fourier transformation. Humic substances were characterized by humifical index E4/E6 and transmissional vibratile spectrums. The last aim of diploma thesis were the characterization of soil HS extracts and compost by acidimetral titration. For each sample was calculated value of H+ ionts amount of substance from measured titrational curves.
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Development and optimization of ointment preparation for burn healing
Müllerová, Kristýna ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
This bachelor's thesis aims to prepare ointments based on an ointment base with the addition of a bioactive component of chlorophyll according to a recipe from an unknow doctor. The basic characteristic of emulsions was performer in the theoretical part, their instability and possible methods of stabilization were described. Furthermore, the reader is acquainted with the bioactive substance of chlorophyll, selected ointments for the healing of burns and wounds and finally with the use in medicine. In the Experimental part, the preparation of emulsion bases of ointment was described. Based on a performed analysis of stability using analytical centrifuge, two ointments bases were selected, to which other components were added – chlorophyll, beeswax, and chamomile extract. The stability of completely prepared ointments was studied at 25 °C and 37 °C, this analysis was performed even after a longer time interval. Using ATR-FTIR spectrometry the present functional groups were identified at prepared ointments, individual components of the ointments base and chlorophyll. Based on the stability measurement of the prepared ointments and rheological measurements (oscillation and rotational measurements), it was evaluated that the best properties were shown by the prepared ointment with an ointment base consisting of 30 wt. % white vaseline and 70 wt. % synderman.
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Carbon nanoparticles from lignite
Kohoutková, Eliška ; Enev, Vojtěch (referee) ; Pekař, Miloslav (advisor)
These bachelor thesis focuses on lignite as a potential raw material for the carbon quantum dots extraction. There was proposed mechanochemical process of isolation these nanoparticles from lignite based on literature search. Lignite was mechanically stressed and subsequently oxidized to hydrogen peroxide. The results show that proposed method will have to be modified but lignite could be used as a feedstock for the carbon quantum dots extraction.
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Optimization of the Methodology for Assessment of Biochar Effect on the Growth of Model Plants
Štorková, Natálie ; Enev, Vojtěch (referee) ; Kalina, Michal (advisor)
This bachelor thesis is studying the effect of biochar on the growth of model plant and deals with the optimalization of the methods for assessing its impact. Theoretical part describes the properties and utilization of soil conditioners, special attention is focused on biochar. According to the literature research, maize (Zea mays) was chosen as a model plant for cultivation experiment and subsequently the application doses of biochar were also defined. The cultivation experiment took place in growing box under controlled illumination and irrigation. Plant dry weight weighing after cultivation, continuous measurement of plant height during the cultivation and also image analysis of the root system were used for evaluating the influence of biochar on quantitative and qualitative properties of model plants. From obtained data it can be summarized that the growth differences were influenced by the application dose, the type of biochar and also by type of soil, which was used for the cultivation experiment.
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Molecular organization of humic acids in solutions
Chytilová, Aneta ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
The diverse structure and content of the highly varied functional groups of humic acids determine these substances as a worthwhile study material for a number of scientific institutions. Above all, the structure causes a wide range of their interesting properties, especially spectral, colloidal, electrochemical, ion-exchange and adsorption properties. Humic acids have variety of utilization in the industry while they have been the subject of a range of further research and development. The character of these complex heterogeneous polydisperse substances is mainly cyclic and aromatic, which according to some studies results in their brown color. Generally, there are multiple theories assuming their potential secondary structure. The aim of this study is the analysis of structure and conformation of humic acids in aqueous solutions. For the purposes mentioned above a concentration series of humic acids have been prepared in four different mediums: 0,1 M NaOH, humic acids in water with pH modified to 12 (basic medium), 0,1 M NaOH + 0,1 M HCl, 0,1 M NaCl (neutral medium). In order to study conformations several analytic methods have been used: ultraviolet and visible spectroscopy, dynamic light scattering, electrophoretic light scattering, potentiometric determination of pH and direct conductimetry. Throughout the experimentation the emphasis was mainly on the purity of humic acids extracted from lignite.
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Application of thin layer chromatography (TLC) for fractionation of humic substances.
Hegrová, Nela ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
The main aim of this Bachelor thesis was to suggest and optimize a method of fractionation of organic matter of humic substances using thin-layer chromatography (TLC). HS Pahokee Peat standards have been characterized by thermochemical and spectrometric techniques such as thermogravimetry, elemental analysis, UV-Vis and Fourier-transform infrared spectrometry. Molecular absorption spectrometry in the ultraviolet and visible range of electromagnetic radiation and steady-state fluorescence spectrometry were used for physicochemical characterization of organic fractions. Using fluorescence spectrometry, humic substances were found to be composed of fluorophores of humic and non-humic (protein) character. Organic fractions corresponding to the humic fluorphores were characterized by a higher aromaticity, average molecular weight and higher content of oxygen substituents on the aromatic nucleus. In contrast, the organic fractions corresponding to the protein constitutional units were distinguished by low values of the humification index. These tell us about microbial origin of these organic substances during the genesis of HS Pahokee Peat.
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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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Interactions of pharmaceuticals with humic acids
Libiger, Jan ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
The bachelor thesis is focused on interaction of drugs with humic substances, which are part of organic soil matter. The results would help in understanding the behavior of drugs in soil and other natural systems. Three drugs were selected. Humic acid was selected as a sorbent, which was extracted from lignin, the lower one is assumed to be the same as that in organic soil. Based on a comparison of the measurement results using the UV-VIS method, it was determined how much the acid of the given drug is able to absorb and how much it is released back into the water. The theoretical part deals with the information about soil organic matter, with the information about humic substances, with the information about drugs such as ibuprofen, sulfamethoxazol or sulfapyridine. Furthermore, the theoretical part deals with methods of analysis.
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