National Repository of Grey Literature 136 records found  beginprevious31 - 40nextend  jump to record: Search took 0.00 seconds. 
Cleaning of biogas by the PSA (pressure swing adsorption)
Navrátil, Petr ; Houdková, Lucie (referee) ; Leštinský, Pavel (advisor)
The topic of this master thesis is upgrading of biogas. As a mixture of gases produced during anaerobic digestion, contains methane which is highly energy valuable gas. But also other substances that we want to remove. We will present the motivation for upgrading biogas and the possibility of separation, generally the pressure swing adsorption method. The key parameter of this technique is the choice of a suitable adsorbent. This is possible based on the knowledge of adsorption processes, therefore, is also described below. The objective of this thesis is to determine the parameters of the pressure swing adsorption metod. To do this it is necessary to determine the adsorption capacity of the adsorbent, measure breakthrough curves of carbon dioxide and methane, and determine the pressure drop of solid bed, etc. As a result we can finally make a balance and evaluate the applicability in practice.
Interactions of humic hydrogels with cupric ions
Lang, David ; Gregorová, Eva (referee) ; Klučáková, Martina (advisor)
This diploma thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis, there was studied the adsorption of copper ions on the provided gels. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then precipitated with hydrochloric acid or metal chlorides. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, thus in the case of gels sequestered metal ions extracted higher.
Sorption heat pump
Veselý, Josef ; Štelcl, Otakar (referee) ; Pospíšil, Jiří (advisor)
This thesis deals with the issue of sorption heat pumps. The theoretical part is devoted to a detailed description of the function of adsorption and absorption heat pumps. For a better understanding of the adsorption cycle is computed theoretical thermal cycle and the heating factor of zeolite adsorption heat pump are computed. The practical part is focused on the design absorption heat pump that works in conjunction with a natural gas boiler. The pump is designed for cooling flue gas condensing boiler and the possible use of thermal energy from other low-temperature source. The thesis contains a thermal calculations, engineering design and structural design of the heat pump.
Developement and validation of method for ferulic acid isolation from wheat bran
Nábělek, Jakub ; Obruča, Stanislav (referee) ; Pořízka, Jaromír (advisor)
This master thesis deals with an optimization of processes of isolation of ferulic acid from wheat bran. Process of isolation based on alkaline hydrolysis from the substance and its adsorption was tested. In the theoretical part were described wheat bran, adsorption proces and used methods. For adsorption were tested five types of adsorbents. Especially these adsorbents: activation carbon (2,53 ± 1,16 mg.l-1), Amberlyst A-21 (105,73 ± 11,87 mg.l-1, Amberlit XAD-16 (241,55 ± 10,42 mg.l-1), Amberlit IRA-900Cl (5,90 ± 0,68 mg.l-1) and Amberlit IRA-96 (189,16 ± 6,49 mg.l-1). As the most efficient adsorbent was determine Amberlit XAD-16. The whole process has underwent detailed optimization in order to maximize the purity of the final product. The isolate was characterized by HPLC and FTIR techniques for ferulic acid and related phenolic acids. Based on FTIR analysis was discovered that the isolate was contamined by proteins. A purification procedure based on deproteination of the raw material before the hydrolysis itself was proposed. As the ultimate solution that eliminated the presence of proteins in the isolate was determine ultrafiltration with capture of molecules with Mw > 10 KDa. Ferulic acid yield from one kilo of wheat bran was 1,00 ± 0,22 g.
The Study of Aditives and Admixture Influence on High-Performance Concrete Properties
Šiler, Pavel ; Bílek, Vlastimil (referee) ; Brandštetr, Jiří (referee) ; Havlica, Jaromír (advisor)
The aim of this work was to develop the method for the determination of the superperplasticizers (SP) content in the water solution. The method developed was then applied to study the SP adsorption on the individual components used for high-performance concrete and the influence of the temperature and pH values over this adsorption. Furthermore the influence of the water to binder ratio, SP, finely grounded granulated blast furnace slag, fly ash, silica fume, finely ground silica sand and bauxite on the hydration process was studied by means of isoperibolic, isothermal and solution calorimetry. The compressive and flexural strength of most samples used in calorimetric experiments was also determined.
Utilization of flow-through coulometry for study of reactivity of humic acids
Pavlíková, Marcela ; Sýkorová,, Ivana (referee) ; Klučáková, Martina (advisor)
Humic acids are part of humus material abounded in nature. Humic acids are generally aromatic stuffs with sidechains and there can be linked various functional groups as carboxylic and fenolic mainly. This functional groups are able to form transitions elements ions and complexes of different stability. This property can be used in the environment, because certain polutants should be imobilized in nature. Diploma thesis studies adsorption of metal ions Cu2+, Cd2+, Zn2+ and Pb2+ on humic acids by electroanalytical method called flow – through coulometry.
Interaction of Ibuprofen with Humic Substances and Stability of Formed Complexes
Vlašicová, Silvie ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
Nowadays, huge amounts of drugs get into watercourses and soil due to wrong disposal in sewage treatment plants. In this work, the sorption and desorption behavior of Ibuprofen in the soil system was studied, especially in relation to humic acids. The degree of sorption and desorption was defined from the change in ibuprofen concentration analyzed by UV-VIS spectrometry, changes in conductivity and pH were also observed. Ibuprofen shows good sorption properties, desorption was really minimal. It can be assumed that there is a strong bond between ibuprofen and both soil and lignite humic acids and therefore there is no risk of leaching back into solutions. Therefore, if ibuprofen entered the environment, it would be sorbed into the humic acids contained in lignite or soil, which means that it should not be harmful in any way.
Utilization of biogas in gas distribution system
Frühbauer, Zdeněk ; Niesner, Jakub (referee) ; Dvořák, Radek (advisor)
The thesis deals with the technologies upgrading the biogas to the quality of the natural gas for the following use in the gas distribution system. The main concern of the thesis is the pressure swing adsorption (PSA), which is nowadays one of the most exploited technologies. For a certain flow and composition of the biogas, completely new PSA technology was designed. Technological schema was created and the main technological devices (adsorbers) were drawn up together with the design documentation for this new technology. The important part of the thesis is also the model of the whole PSA technology in the ChemCAD programme and the evaluation of the operating and investment costs.
Adsorption of metal ions on humic acids
Pokorná, Markéta ; Mgr. Martina Havelcová, Ph.D (referee) ; Klučáková, Martina (advisor)
The Bachelor´s thesis deals with humic acids and their ability to bind metal ions on their surface. Humic acids are generally aromatic polycyclic compounds, which contain phenolic and carboxylic functional groups on their sidechains. Because of their functional groups, they are able to form stable complex compounds. In this thesis, the adsorption of lead ions was studied by electroanalytical method called flow-through coulometry.
Reactivity of modified humic gels
Lang, David ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis the adsorption of copper ions on humic gels was studied. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then by precipitating with hydrochloric acid or magnesium chloride. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, Thus the extracted amounts are bigger.

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