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Alkaloid decomposition by electric discharges in liquids
Jonisová, Lenka ; Kozáková, Zdenka (oponent) ; Krčma, František (vedoucí práce)
Plasmachemical processes are one of the methods used for wastewater treatment. Sewage and household wastewaters include a variety of organic substances that must be removed to reuse water in industry or households. The aim of this diploma thesisisthe observation of alkaloids decomposition by plasma chemical process. The theoretical part is focused on plasma generation in liquids and characterization of selected alkaloids. The decomposition of caffeine and quinine in direct current electrical discharge in liquid with diaphragm configuration is investigated in this work. The experiments were carried out in a batch reactor divided into two parts by a diaphragm made from ceramic material ShapalTM-M (thickness 3.0 mm, pin-hole diameter 1.0 mm). The stainless steel electrodes of 5×12 cm size were used. The mean electric power was set to 135 W for an operation time of 60 minutes in each experiment. Caffeine solutions (total volume of 4 L) were prepared in concentrations of 10, 25 and 50 ppm, quinine solutions in concentrations of 5, 10 and 15 ppm. The initial conductivity was adjusted by sodium chloride at three different values – 400, 750 or 1000 µS•cm-1. The experimental part consisted also of using analytical methods necessary for compound quantification. Hydrogen peroxide formation during the electrical discharge was determined by colorimetric method based on generation of yellow complex with titanium(IV) sulfate reagent. The caffeine concentration was measured by UV spectrometric method at wavelength 273 nmand thenHPLC/MS analysis was performed. Quinine degradation was monitored by UV-VIS spectrometry and fluorescent measurements. The plasma generation in water solutions induces formation of hydroxyl radical, hydrogen peroxide, oxygen, hydrogen and other reactive species. Hydrogen peroxide is produced and then utilized in degradation of organic compounds and thus lower concentration of H2O2was measured in solution with caffeine and quinine than in solution without alkaloids. However, the situation is different between cathode chamber and anode chamber. There is only negligible amount of H2O2used on degradation in cathode chamber. In contrary, the considerable degradation of caffeine and quinine and diminished concentration of H2O2 was observed in anode chamber.
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Alkaloid decomposition by electric discharges in liquids
Jonisová, Lenka ; Kozáková, Zdenka (oponent) ; Krčma, František (vedoucí práce)
Plasmachemical processes are one of the methods used for wastewater treatment. Sewage and household wastewaters include a variety of organic substances that must be removed to reuse water in industry or households. The aim of this diploma thesisisthe observation of alkaloids decomposition by plasma chemical process. The theoretical part is focused on plasma generation in liquids and characterization of selected alkaloids. The decomposition of caffeine and quinine in direct current electrical discharge in liquid with diaphragm configuration is investigated in this work. The experiments were carried out in a batch reactor divided into two parts by a diaphragm made from ceramic material ShapalTM-M (thickness 3.0 mm, pin-hole diameter 1.0 mm). The stainless steel electrodes of 5×12 cm size were used. The mean electric power was set to 135 W for an operation time of 60 minutes in each experiment. Caffeine solutions (total volume of 4 L) were prepared in concentrations of 10, 25 and 50 ppm, quinine solutions in concentrations of 5, 10 and 15 ppm. The initial conductivity was adjusted by sodium chloride at three different values – 400, 750 or 1000 µS•cm-1. The experimental part consisted also of using analytical methods necessary for compound quantification. Hydrogen peroxide formation during the electrical discharge was determined by colorimetric method based on generation of yellow complex with titanium(IV) sulfate reagent. The caffeine concentration was measured by UV spectrometric method at wavelength 273 nmand thenHPLC/MS analysis was performed. Quinine degradation was monitored by UV-VIS spectrometry and fluorescent measurements. The plasma generation in water solutions induces formation of hydroxyl radical, hydrogen peroxide, oxygen, hydrogen and other reactive species. Hydrogen peroxide is produced and then utilized in degradation of organic compounds and thus lower concentration of H2O2was measured in solution with caffeine and quinine than in solution without alkaloids. However, the situation is different between cathode chamber and anode chamber. There is only negligible amount of H2O2used on degradation in cathode chamber. In contrary, the considerable degradation of caffeine and quinine and diminished concentration of H2O2 was observed in anode chamber.
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