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Study of volatile hydrocarbon decomposition in non-thermal plasma of gliding arc at atmospheric pressure
Töröková, Lucie ; Rašková, Zuzana (referee) ; Kozáková, Zdenka (advisor)
Diploma thesis deals with gliding arc discharge in non-equilibrium plasma, its properties and usage for dissociation of volatile organic compounds. Plasma techniques create a perspective alternative to classical methods such as adsorption, biofilters, thermal processes, freezing and condensation. The method used for analysis of dissociation products is described in the theoretical part as well. Method is gas chromatography and it is combined with mass spectroscopy. The experimental part contains the overall description of GlidArc reactor where volatile organic compounds were dissociated. The volatile organic compound is brought into the reactor from the reservoir by carrier gas (nitrogen); synthetic air was used as working gas. The reactor is connected to the device for sampling. This device has several openings for sampling by SPME fibre method, sorption tubes method and a special opening for probe entry from the device Testo 350 M/XL, which enables instant analysis of low-molecular compounds. GC-MS was used for determination of high-molecular products of dissociation. Products sorbed on SPME fibres were analysed directly, compounds sorbed by active carbon were extracted by carbon disulphide. Samples obtained using SPME fibres were analysed. The major products of the dissociaton were found due to this analysis, those major products are in the case of hexane: pentanal, 4 methyl-3-pentanal, 2-butoxy-ethanol, pentane a 2-hexene. Major products detected when dissociating cyclohexane were: l,3-dimethyl-butane, propanal, cyklohexanone, 5-hexenal a 2-pentyn-1-ol. Major products of xylene dissociation were methyl-benzene, benzaldehyde, 4-methyl-benzaldehyde, 1-nitroethyl-benzene a benzenmethanol. After analysis obtained using sorption tubes showed that mainly the dissociated compound was sorbed, but the products of the dissociation were presented in too low concentration for an adequate analysis. For that reason the sorption tubes were used only for quantitative determination of the compounds depending on the power supply. The dependence of the dissociation of the compounds on the power supply was observed using SPME fibres which were used for quantitative determination. The Results obtained by both obtained techniques were almost in accordance. Speaking of low-molecular compounds, dissociation of all compounds gave the same products, i.e. carbon dioxide, hydrogen, nitrogen oxide, nitrogen dioxide and water. The results show that the dissociation of VOC gives - besides many potentially dangerous dissociation products - significant amounts of nitrogen oxides which is harmful to the environment. Hence it is necessary to be concerned with problems studied in the future mainly with respect to limitation of NOx generation. It will be possible to optimalize the conditions of the VOC dissociation on the basis of future kinetic analysis.
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Study of chemical processes in the gliding arc discharge by optical emission spectroscopy
Maďarová, Štefánia ; Töröková, Lucie (referee) ; Mazánková, Věra (advisor)
The aim of the bachelor thesis is to study the chemical processes of the glow discharge and the sliding arc under the post discharge conditions. The post discharge or afterglow plasma means that the external source of energy is removed from the system and the relaxation process can start. The experiments in bachelor work were performed under the different experimental conditions, for various pressures and gas mixtures. The theoretical part briefly describes term plasma and kinetic processes occurring in plasma generated by electrical discharges. Also there is described the problem of Titan’s atmosphere and possibility of mimic it by the gliding arc discharge. In the experiments, pure nitrogen and a gaseous mixture of nitrogen and methane were used at the same flow rate and different pressures. Optical Emission Spectroscopy (OES) and Gas Chromatography-Mass Spectrometry (GC-MS) were used to analyze chemical reaction products. The glow discharge was generated by a DC voltage source and the measurement was in flow mode. The total gas pressure ranged from 1 000-4 000 Pa at a nitrogen flow rate of 400 ml / min and methane of 0.025 ml / min. The current was in the range of 85-150 mA. In all experimental conditions, a well-known phenomenon called “pink afterglow” was observed. This phenomenon corresponds to the maximum intensity of radiation in a stagnant discharge, exhibiting a significant increase in characteristic pink radiation. The optical emission spectra of the discharging discharge were scanned in the wavelength range 540-640 nm. Three spectral nitrogen systems (the first and the second positive and the first negative ones) have been identified in the measured spectra, they have maximum values in the so-called " "Pink-afterglow". These maxims dropped with increasing pressure and shifted to a later decay time.
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Surface treatment of biocompatible materials
Kováč, Ján ; Kučera, František (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the study of the influence of plasma discharge on changes in the surface properties of the biomaterial. Surface treatements were performed using three types of plasma discharge: gliding arc, dielectric barrier discharge (DBD) and microwave surface wave discharge. Various gaseous mixtures in plasma discharges and their effect on the surface treatment of the biomaterial were investigated. The selected biomaterial was aliphatic biopolymer polycaprolactone (PCL). It is a suitable surface treatment material, thanks to its biodegradability and easy processability. The PCL supplied by Sigma-Aldrich was in the form of pellets, witch had been converted to foil. The film samples were subsequentely exposed to plasma discharges. To characterize the surface properties of the polymer, surface energy was measured using a sissle drop method, a See System from Advex Instrumnets was used to measure. Based on experimental results, we can confirm that the surface has been modified. However, the plasma discharge modifications have led to hydrophilic and not hydrophobic properties of the biomaterial, with the best results in terms of hydrophilicity being achieved by microwave discharge with surface wave. Due to the negative results of the experiment, bactericidal effects were not investigated.
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Study of chemical reactions products in the prebiotic atmospheres
Manduchová, Ivana ; Slavíček,, Pavel (referee) ; Mazánková, Věra (advisor)
The diploma thesis is focused on the study of chemical reaction products in prebiotic atmospheres. The theoretical part deals with the main theories of composing the atmosphere of the early Earth, hypotheses of the origin of life and genetic code in the form of RNA, the atmosphere of the moon Titan and the basic characteristics of the gliding arc discharge, and the analytical techniques used in the diploma thesis. In the experimental part, study of products was carried out by experimental atmospheric simulations in a special stainless steel reactor in various mixtures of gases N2, CH4, CO2 and O2. The electrical discharge for atmospheric simulation was generated by an electrode configuration for the gliding arc discharge and glow discharge. Detection and identification of chemical reaction products was performed by Gas Chromatography with Mass Spectrometry (GC-MS) and Flame Ionization Detector (GC-FID), Testo 350 M/XL and Proton Transfer Reaction Mass Spectrometry (PTR-MS). A theoretical kinetic model was created to predict and confirm the detected products. During the experiments, the dependence of the product intensity on changes in the composition of the gaseous mixture and the applied value of the electric current was also observed.
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Study of plasma effects on quinine solutions
Procházková, Michaela ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis focuses on quinine solutions and quality of these solutions after applying plasma discharge. These electric discharges can be used to destroy some substances from the water. The theoretical part is focused on description of electric discharges in liquids and on the properties of quinine. In the experimental part, the properties of quinine solutions containing different electrolytes were analysed by UV-VIS spectrophotometer and fluorescence spectroscopy. Two different types of configurations of plasma discharges in liquids were used. Solutions were compared on the base of different concentration of quinine, different electrolytes, different configurations of plasma discharges and pH values of the solutions. Furthermore, the experimental work focuses on quinine solutions with the sodium nitrate. The time instability of the solutions was analysed. Also, the influence of the solution age and different types of the plasma discharge on the excitation and emission spectra of quinine were investigated.
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Study of plasma effects on quinine solutions
Procházková, Michaela ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis focuses on quinine solutions and quality of these solutions after applying plasma discharge. These electric discharges can be used to destroy some substances from the water. The theoretical part is focused on description of electric discharges in liquids and on the properties of quinine. In the experimental part, the properties of quinine solutions containing different electrolytes were analysed by UV-VIS spectrophotometer and fluorescence spectroscopy. Two different types of configurations of plasma discharges in liquids were used. Solutions were compared on the base of different concentration of quinine, different electrolytes, different configurations of plasma discharges and pH values of the solutions. Furthermore, the experimental work focuses on quinine solutions with the sodium nitrate. The time instability of the solutions was analysed. Also, the influence of the solution age and different types of the plasma discharge on the excitation and emission spectra of quinine were investigated.
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Surface treatment of biocompatible materials
Kováč, Ján ; Kučera, František (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the study of the influence of plasma discharge on changes in the surface properties of the biomaterial. Surface treatements were performed using three types of plasma discharge: gliding arc, dielectric barrier discharge (DBD) and microwave surface wave discharge. Various gaseous mixtures in plasma discharges and their effect on the surface treatment of the biomaterial were investigated. The selected biomaterial was aliphatic biopolymer polycaprolactone (PCL). It is a suitable surface treatment material, thanks to its biodegradability and easy processability. The PCL supplied by Sigma-Aldrich was in the form of pellets, witch had been converted to foil. The film samples were subsequentely exposed to plasma discharges. To characterize the surface properties of the polymer, surface energy was measured using a sissle drop method, a See System from Advex Instrumnets was used to measure. Based on experimental results, we can confirm that the surface has been modified. However, the plasma discharge modifications have led to hydrophilic and not hydrophobic properties of the biomaterial, with the best results in terms of hydrophilicity being achieved by microwave discharge with surface wave. Due to the negative results of the experiment, bactericidal effects were not investigated.
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Study of chemical reactions products in the prebiotic atmospheres
Manduchová, Ivana ; Slavíček,, Pavel (referee) ; Mazánková, Věra (advisor)
The diploma thesis is focused on the study of chemical reaction products in prebiotic atmospheres. The theoretical part deals with the main theories of composing the atmosphere of the early Earth, hypotheses of the origin of life and genetic code in the form of RNA, the atmosphere of the moon Titan and the basic characteristics of the gliding arc discharge, and the analytical techniques used in the diploma thesis. In the experimental part, study of products was carried out by experimental atmospheric simulations in a special stainless steel reactor in various mixtures of gases N2, CH4, CO2 and O2. The electrical discharge for atmospheric simulation was generated by an electrode configuration for the gliding arc discharge and glow discharge. Detection and identification of chemical reaction products was performed by Gas Chromatography with Mass Spectrometry (GC-MS) and Flame Ionization Detector (GC-FID), Testo 350 M/XL and Proton Transfer Reaction Mass Spectrometry (PTR-MS). A theoretical kinetic model was created to predict and confirm the detected products. During the experiments, the dependence of the product intensity on changes in the composition of the gaseous mixture and the applied value of the electric current was also observed.
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Study of chemical processes in the gliding arc discharge by optical emission spectroscopy
Maďarová, Štefánia ; Töröková, Lucie (referee) ; Mazánková, Věra (advisor)
The aim of the bachelor thesis is to study the chemical processes of the glow discharge and the sliding arc under the post discharge conditions. The post discharge or afterglow plasma means that the external source of energy is removed from the system and the relaxation process can start. The experiments in bachelor work were performed under the different experimental conditions, for various pressures and gas mixtures. The theoretical part briefly describes term plasma and kinetic processes occurring in plasma generated by electrical discharges. Also there is described the problem of Titan’s atmosphere and possibility of mimic it by the gliding arc discharge. In the experiments, pure nitrogen and a gaseous mixture of nitrogen and methane were used at the same flow rate and different pressures. Optical Emission Spectroscopy (OES) and Gas Chromatography-Mass Spectrometry (GC-MS) were used to analyze chemical reaction products. The glow discharge was generated by a DC voltage source and the measurement was in flow mode. The total gas pressure ranged from 1 000-4 000 Pa at a nitrogen flow rate of 400 ml / min and methane of 0.025 ml / min. The current was in the range of 85-150 mA. In all experimental conditions, a well-known phenomenon called “pink afterglow” was observed. This phenomenon corresponds to the maximum intensity of radiation in a stagnant discharge, exhibiting a significant increase in characteristic pink radiation. The optical emission spectra of the discharging discharge were scanned in the wavelength range 540-640 nm. Three spectral nitrogen systems (the first and the second positive and the first negative ones) have been identified in the measured spectra, they have maximum values in the so-called " "Pink-afterglow". These maxims dropped with increasing pressure and shifted to a later decay time.
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Study of volatile hydrocarbon decomposition in non-thermal plasma of gliding arc at atmospheric pressure
Töröková, Lucie ; Rašková, Zuzana (referee) ; Kozáková, Zdenka (advisor)
Diploma thesis deals with gliding arc discharge in non-equilibrium plasma, its properties and usage for dissociation of volatile organic compounds. Plasma techniques create a perspective alternative to classical methods such as adsorption, biofilters, thermal processes, freezing and condensation. The method used for analysis of dissociation products is described in the theoretical part as well. Method is gas chromatography and it is combined with mass spectroscopy. The experimental part contains the overall description of GlidArc reactor where volatile organic compounds were dissociated. The volatile organic compound is brought into the reactor from the reservoir by carrier gas (nitrogen); synthetic air was used as working gas. The reactor is connected to the device for sampling. This device has several openings for sampling by SPME fibre method, sorption tubes method and a special opening for probe entry from the device Testo 350 M/XL, which enables instant analysis of low-molecular compounds. GC-MS was used for determination of high-molecular products of dissociation. Products sorbed on SPME fibres were analysed directly, compounds sorbed by active carbon were extracted by carbon disulphide. Samples obtained using SPME fibres were analysed. The major products of the dissociaton were found due to this analysis, those major products are in the case of hexane: pentanal, 4 methyl-3-pentanal, 2-butoxy-ethanol, pentane a 2-hexene. Major products detected when dissociating cyclohexane were: l,3-dimethyl-butane, propanal, cyklohexanone, 5-hexenal a 2-pentyn-1-ol. Major products of xylene dissociation were methyl-benzene, benzaldehyde, 4-methyl-benzaldehyde, 1-nitroethyl-benzene a benzenmethanol. After analysis obtained using sorption tubes showed that mainly the dissociated compound was sorbed, but the products of the dissociation were presented in too low concentration for an adequate analysis. For that reason the sorption tubes were used only for quantitative determination of the compounds depending on the power supply. The dependence of the dissociation of the compounds on the power supply was observed using SPME fibres which were used for quantitative determination. The Results obtained by both obtained techniques were almost in accordance. Speaking of low-molecular compounds, dissociation of all compounds gave the same products, i.e. carbon dioxide, hydrogen, nitrogen oxide, nitrogen dioxide and water. The results show that the dissociation of VOC gives - besides many potentially dangerous dissociation products - significant amounts of nitrogen oxides which is harmful to the environment. Hence it is necessary to be concerned with problems studied in the future mainly with respect to limitation of NOx generation. It will be possible to optimalize the conditions of the VOC dissociation on the basis of future kinetic analysis.
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