čas: 23.4.2021 00:05:50
Obnovit | RAW
Department of Solid State Chemistry
List of available PhD theses
Bioaccesibility of antimony in urban traffic-loaded areas
Antimony (Sb) has not been well known and widely cited toxic elements yet, but it can posed a serious environmental risk in future. Sb compounds are used in industrial sphere as fire-resistant agents, hence the increased Sb concentration represents a challenge for geochemical and material research. The aim of this work is to study the stability of Sb compounds incoming to the environment and their subsequent behaviour in the soil-groundwater-surface water system. Geochemical properties of antimony and arsenic will be compared in term of their environmental stability and bioaccesibility. Next part of the work will be focused on the monitoring of selected heavily contaminated locality.
Environmental accessibility of selenium in power plant fly ashes
Selenium belongs both to esential and toxic elements, where the boundary between them is very thin. Power plant fly ashes deposited in landfills represent an important antrhropognic sourse of selenium. The stability of selenium in fly ashes is primarily affected by the quality of burned coal and actual combustion technology. In addition, the age of fly ash and the geochemistry of landfill area can play important role in selenium mobility at the place of its occurrence. The aim of the PhD Thesis will be to characterize the structure, mineralogical and chemical composition and surface properties of different types of fly ash. The next step will be to determine the amount and major forms of Se in fly ash (by sequential leaching), and to study their stabilty and interaction with surrounding environment, i.e. with soils, sediments, surface water and groundwater. The obtained results should help to estimate the gradient of environmental availability of selenium, together with its potential ecological risk.
Growing Single Crystals and Structure Analysis of Multiple Component Crystals
API's multiple-component crystals are a valuable option in modfying pharmacokinetic profile, stability of API etc. The application properties of any particular active compound are often rendered by means of the component is built in the structure. This work aims to prepare single crystals of salts, solvates, co-crystals and polymorphs of selected compounds, study potentional temperature dependent phase transitions, their complex characterization using a bundle of analytical methods accenting X-ray structure analysis and consequent correlation of parameters and solvent occupied voids.
Hydratation and adsorption properties of waste aluminosilicates in water management
Aluminosilicates, together with e.g. powdered building waste, biochar, lignin are able to adsorb and keep a large amount of water compare to soils and sediments. The mixing of these materials with selected soils in controlled dosages can support water retention in soils, which is significant due to more and more often "dry periods" and generally lower precipitation. A controlled dosage of the material with high water retention to soil ecosystems can improve markedly a water regime and hydrological cycle.
Inorganic carriers of active pharmaceutical ingredients
The work is focused on development of new solid dosage forms. Release of active pharmaceutical ingredient and its stability against degradation can be considerably affected after its incorporation into a carrier. Inorganic compounds with layered structure, namely the layered double hydroxides suitable for intercalation of negatively charged anionic species, will be used as the host structures. Methods for preparation of intercalates, interactions between the host structure and drugs intercalated in interlayer, stability of intercalated drugs, and their back release in simulated body fluids will be studied.
Pharmaceutical substances chirality identification from powder diffraction data
Pharmaceutically interesting compounds are often not available in a form of crystals suitable for single crystal X-ray structure determination. The structure can be determined from powder - unfortunately standard experiment make chirality determination impossible. The main aim of this work will be to calibrate the crystal structure by adding an ion or cocrystallization partner with known chirality.
Pharmaceutical substances crystal structure solution by combination of data from ss-NMR, structure prediction and powder diffraction
When we have no singe crystal diffraction data available we can solve the structure from alternative experiments. We can predict the structure and confirm the prediction by experimental and theoretical ss-NMR data comparison. The process can be combined with data obtained by powder diffraction. The target of this work is to test this synthetic approach for crystal structure solution.
Preparation of organic single crystals based on pharmaceutical materials and characterization of their properties
Topic of this work will be focused on preparation and crystal growth of volatile and subliming organic compounds with accent on active pharmaceutical ingredients (polymorhps, solvates, salts or cocrystals) from gaseous phase and solution in order to prepare large-volume crystals thereof. The work will be focused on sublimation apparatus design and optimization of the crystal growth procedure of organic compounds from gaseous state using horizontal two section resistive furnace with separate temperature regulation. This method is based on transferring (subliming) the starting material into gaseous state in the storage part of the growth system and its subsequent crystallization (desublimation) in the dedicated coolest place of the system. Setting of suitable temperature regime in both furnace sections defines and controls the growth rate of growing crystal. An integral part of the work comprises: (i) a new crystallization container divided into storage and crystallization stages will be designed, (ii) growth conditions (temperature gradient in the furnace, temperature regimes) will be optimized, and (iii) the physical, structural and optical properties of the prepared crystals will be characterized. Second part of this work will be focused on preparation of crystals of model organic compounds grown from solution. The solvents influence on the crystallization process and final crystal quality will be evaluated. Results of characterizations performed on crystals obtained from diverse procedures as well as of used procedures will be compared.
Stability of soil ternary complexes with toxic oxyanion (As/Sb/Se). Effect of iron and organic carbon.
In soil profiles several toxic elements (arsenic, antimony, selenium) occur as oxyanions primarily bound to HFO phases, forming stable surface complexes. This process runs as the balanced adsorption of oxyanions from a soil solution to active adsorption sites of soil particles, in the presence of another anions and dissolved organic matter. During this process the binary and/or ternary soil complexes of HFO, organic matter and oxyanion have been formed. The adsorption and complexation proceed in a colloid environment, which is susceptible to the ionic strength of soil solution (stabilization or aggregation of particles). According to recent results the stability of formed ternary complexes is critical for the long-term stability of binding oxyanions. The aim of this work will be to qualify the formation of organic matter – ferric oxide – anionic particle ternary komplexes, to describe their structure and binding properties, and to estimate the environmental impact to the stability of complex components, particularly the toxic oxyanionic forms.
Supported catalysts with active layer of mixed transition metal oxides
The work is focused on preparation of catalytically active mixed oxides of transition metals deposited on preformed metal and ceramic supports. Modification of supports surface, coating with oxide interlayers for active components anchoring, and subsequent deposition of the catalytically active binary and ternary Ni, Cu, Co, and Mn mixed oxides will be studied to achieve good adhesion of the deposited oxides to the supports. The aim of the work is to obtain a complex information about the role of supports surface pretreatment, procedure of precursors deposition, and following thermal treatment on the composition, physical chemical properties, and catalytic activity of the deposited mixed oxide catalysts.