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Environmental characteristics of mineral waste from metallurgy
Vítková, Martina ; Ettler, Vojtěch (advisor) ; Bollinger, Jean-Claude (referee) ; Dijkstra, Joris J (referee)
Mineralogical and geochemical characteristics of metallurgical wastes from the Cu-Co smelters situated in the Zambian Copperbelt have been investigated. A number of instrumental analytical methods (XRD, SEM/EDS, EPMA, TEM/EDS) has been used to identify primary and secondary phases in smelter slags and dusts. A set of leaching experiments (CEN/TS 14997 pH-static test, EN 12457 batch test) in combination with geochemical modelling has been performed, with the emphasis on the leaching behaviour of potential contaminants and their release as a function of the pH. The effect of sample preparation on metal leachability from slag was also evaluated, considering the grain size reduction required by the standardised leaching protocols. Environmental and health risk assessments of the dust samples have been performed. It was shown that the main carriers of metals in the studied slags were Cu sulphides (bornite, digenite, chalcocite), Co sulphides (cobaltpentlandite), Co-bearing intermetallic phases and alloys. Copper and cobalt were detected in major silicates and spinels, substituting for Fe or Mg in their structures, and in glass. The presence of secondary metal-bearing phases observed on the slag surfaces indicated the reactivity of the slags on contact with water/atmosphere. It was reported that in...
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Interaction of 7,8-dihydroxyflavone with physiological metals
Streďanská, Aneta ; Mladěnka, Přemysl (advisor) ; Červený, Lukáš (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Aneta Streďanská Supervisor: prof. Přemysl Mladěnka, Pharm.D., PhD. Consultant: Zuzana Lomozová, Pharm.D., PhD. Title of thesis: Interactions of 7,8-dihydroxyflavone with physiological metals 7,8-dihydroxyflavone belongs to the phenolic substances collectively referred to as flavonoids. Flavonoids are bioactive components abundantly distributed in the daily diet with the ability to modulate health and disease through miscellaneous mechanisms including their antioxidant activity. However, they can also exhibit prooxidative effects under certain conditions. Due to this fact, which is related to individual factors, i.e. presence of various substitutions on the flavonoid come, it is therefore essential to understand the redox behavior based on the relationship between structure and effect and to understand their physiological, pharmacological and thus also potential toxic properties. The interaction with physiological metals is determined by the structure of the molecule through the dihydroxy moiety in positions 7 and 8. These mentioned metals are essential for many biochemical processes in biological systems. Their homeostasis is strictly regulated in the human body and disruption of this...
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Analysis of locally modified surfaces for selective growth of cobalt
Krajňák, Tomáš ; Bábor, Petr (referee) ; Čechal, Jan (advisor)
In this thesis the chemical composition of silicon substrates locally modified by focused gallium ion beam by X-ray photoelectron spectroscopy is determined. In order to determine the influence of focused ion beam, the sample comprising sputtered square areas with nominal depths in range of 1 to 10 nm was prepared. Next, the sample was heated to elevated temperatures (500 - 700 °C) to reveal changes in the sputtered areas induced by annealing. In this work by X-ray photoelectron spectrometer Kratos Supra and electron microscope Tescan LYRA3 with focused ion beam were used. From the measured spectra of the Si 2p and Ga 2p3/2 peaks measured as a function of nominal sputtering depth and annealing temperature the following main observations were obtained. First, there is the additional peak component in the Si 2p peak, which can be assigned to the amorphous silicon. The second important finding is that gallium can be removed from near surface volume by annealing at temperatures beyond 700 °C.
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The circulation of cobalt in the environment
Charuza, Martin ; Mládková, Zuzana (referee) ; Sommer, Lumír (advisor)
This bachelor thesis deals with importance of cobalt in the environment, especially as a component of B12 vitamin. Vitamin B12 is a complex, that is necessary for proper formation of blood corpuscules and DNA, except that affects many others procesess in the body. Cobalt forms many complex compounds, which are discussed in this work. The most common oxidation number in compounds are +II and +III. The second part describes spectrophotometric determination of cobalt with suitable reagents. There are a lot of spectrophotmetric reagents for cobalt determination in a sample. The most widely used spectrophotometric reagents for determination of cobalt are 4-(2-pyridylazo)resorcinol (PAR), 1-(2-pyridylazo)-2-naphtol (PAN), 2-(5-Brom-2-pyridylazo)-5-diethylaminophenol (5-Brom-PADAP), 4-(2-thiazolylazo)resorcinol (TAR) a 2-(2-thiazolylazo)-4-methoxyphenol (TAMP). All of theese reagents are heterocyclic azodyes. Cobalt is bonded on this azodyes by coordination covalent bond and forms stable complex.
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Ellipsometry of Thin Films
Novotný, Zbyněk ; Navrátil, Karel (referee) ; Nebojsa, Alois (advisor)
Diploma thesis deals with ageing process of thin films of Co and Cu on Si substrate, prepared by the IBAD method. The process of film ageing, which depends on time of exposition to the atmosphere at room conditions, was investigated with spectroscopic ellipsometry (VIS+UV) and atomic force microscopy. In case of thin Co films, approximately four days long incubation period was observed. During this time period, a change in the optical parameters of the film occurs without a measurable change of the film topography. Using non-contact atomic force microscopy, a growth of the transitional film in the island growth regime was observed. During the ageing of thin Cu films, two stages of growth of the transitional layer were observed - nucleation stage and growth stage. Both of these time periods of the transitional layer growth show direct logarithmic dependence. Using non-contact atomic force microscopy, the growth of the transitional film was observed. Using atomic force microscopy in non-contact regime, time dependent measurement was done and the process of forming of one monolayer of the transitional layer was documented. Within the diploma thesis, a series of experiments on ultra high vacuum system were performed in order to investigate phase transformation of thin Fe films (22 monolayers) on Cu(100) stabilized by CO absorption. The transformation from fcc phase to bcc phase was induced by Ar+ ion beam bombardment with the ion energy in the range (0.5-4) keV. The process of phase transformation was observed by surface magneto-optic Kerr effect, Auger electron spectroscopy and low energy electron diffraction.
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Epitaxial growth of cobalt islands via oxide mediated epitaxy
Stará, Veronika ; Kolíbal, Miroslav (referee) ; Čechal, Jan (advisor)
This bachelor thesis deals with preparation, growth and analysis of cobalt thin films. The films are formed on silicon (111) samples covered with a thin layer of native oxide SiO2. Cobalt thin films were prepared using oxide mediated epitaxy method with the effusion cell as a source of cobalt atoms. Composition and morphology of the resulting Co system was studied as a function of the annealing temperature. Another goal of this research was to determine the dependence of the final island shape on the amount of deposited material and substrate orientation. The prepared structures were analyzed using X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. To determine the thickness of subsurface islands the samples were etched in buffered hydrofluoric acid and analyzed using above mentioned methods.
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Leachability of Cu, Ni and Co from alkali-activated matrices
Janíčková, Vlasta ; Kalina, Lukáš (referee) ; Koplík, Jan (advisor)
The work deals with the determination and comparison of leaching of heavy metals from two types of alkali activated systems based on blast furnace slag and high-temperature fly ash. These systems are capable in their structure encapsulate heavy metals, toxic substances or radioactive substances, which can be harmful for the environment. The aim of this work is to prepare a mixture with acceptable mechanical properties. Leachibility from matrix was tested according to ČSN EN 12457–4, followed by analyses Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Structure of matrix was analysed using Scanning electron microscope (SEM).
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Deposition of magnetic nanostructures using EBID and optimalization of their chemical composition and morphology
Vyroubal, Ondřej ; Kolíbalová, Eva (referee) ; Kolíbal, Miroslav (advisor)
This master's thesis deals with deposition of cobalt nanostructures using Electron Beam Induced Depositon (EBID). The thesis firstly describes theoretical background regarding EBID. In the following experimental part, the deposition process is optimized via analysis of exposition parameters and their influence on the final shape of nanostructures. These are analyzed via Atomic Force Microscopy (AFM). Optimized exposure parameters are then applied to the deposition of functional 3-dimensional nanostrucutres. In particular, the deposition of cobalt spheres. The elemental composition is analyzed by the means of element composition using Energy-dispersive X-ray Spectroscopy (EDX) and the nanostructures of desired morphologies are studied with Magnetic Force Microscopy (MFM) and Magneto-Optical Kerr Microscope).
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