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Soil is one of the natural habitats of microorganisms that are significantly involved in the continuous transformation of organic and inorganic substances. The issues currently faced by this area of research are based on the occurrence of extraneous synthetic substances (xenobiotics) in the environment. These xenobiotics do not have a natural origin but have been artificially synthesized by humans. The contamination of the xenobiotic environment occurs with the development of human economic activity (industry and agriculture); xenobiotics are resistant to degradation processes, accumulate in soil and act on microorganisms. Biogenic substances are, by way of exception, easily decomposable. Few studies have been conducted to analyze the relationship between the occurrence of biogenic and xenobiotic substances in soil and their effects on microorganisms. The aim of this dissertation was to gain knowledge about the influence of biogenic and xenobiotic substances on the metabolism of soil microorganisms and to improve the procedures used to evaluate the influence of chemicals applied to the soil. This dissertation is also devoted to the study of soil enzymes. The dissertation is divided into two parts. The first theoretical part is further divided into: a) a review article on adsorption of enzymes to the solid soil component and factors limiting their activity. This review article summarizes some of the important findings published in the scientific literature and provides information on adsorption of enzymes to the solid soil component and factors limiting their activity. The first part of this review article discusses in particular the problems of enzyme interactions with the solid soil component and enzyme adsorption kinetics. In the second part of this paper I deal with the issue of factors that can affect the activity of adsorbed enzymes (b) An overview on lignin. This review article summarizes the knowledge about the chemical composition of lignin and its content in forest soils, lignin biodegradation and microorganisms producing ligninolytic enzymes; lignin peroxidase, manganese-dependent peroxidase and other versatile peroxidases are amongst the most conspicuous ligninolytic enzymes. (c) An article on the influence of agrochemicals on soil and soil micro-organisms. The aim of this review article was to summarize the knowledge of the influence of agrochemicals on sustainability and soil health. The second experimental part contains knowledge about the effects of xenobiotic (chlortetracycline and sulfapyridine) and biogenic substances (ascorbic acid and amino acids) on soil microorganisms. The results obtained showed the effect of chlortetracycline and sulfapyridine on the activity of soil enzymes depending on the enzyme studied and the antibiotic used. Within this experimental part, the influence of oxytetracycline and sulfamethoxazole on the structure and function of the microbial community in the soil was also studied. The results obtained showed the different effects of both tested antibiotics on cumulative respiration and carbon microbial biomass in soil. In the framework of this dissertation, a study of respiration of forest soils after application of ascorbic acid and amino acids was also carried out. The results obtained from these experiments showed an increase in respiratory activity after administration of ascorbic acid or ascorbic acid in combination with amino acids, depending on the properties of the soil samples tested; maximum respiratory activity in acidic soils was induced after the addition of L-glutamic acid and alkaline soils after the addition of beta-alanine. The size of the mesh holes has a significant effect on soil disturbance that affects pore structure, fungal hyphae, fungal fraction and bacterial fraction. The effects are dependent on the soil type and the vegetation cover. Sifting through 2 mm sieve increases the mineralization of exogenously supplied carbohydrates and phenolic substances compared to 5 mm and the sieve of significant importance (p <0.05), especially in organic horizons, due to increased microbial metabolism and changes in other soil properties.

The main objective of this work was to evidence versatile applications of ordered siliceous mesoporous materials, especially in adsorption and catalysis. For these reasons four mesoporous molecular sieves (SBA-15, SBA-16, MCM-41, and MCM-48) with different structures and textural properties have been chosen. To show the possible application of mesoporous molecular sieves as a CO2 adsorbent, magnesium oxide, and potassium carbonate were incorporated into SBA-15, SBA-16, and MCM-48 silicas. In order to avoid destruction of silica supports, a novel procedure based on the precipitation of magnesium acetate on the silica surface was developed. Subsequent in situ chemical conversion of magnesium acetate provided magnesium oxalate, while magnesium oxide was formed by calcination. To introduce potassium carbonate, silica modified with MgO was impregnated with potassium oxalate followed by its conversion to carbonate. All prepared mesoporous adsorbents preserved characteristic features of mesoporous molecular sieve (large surface areas, narrow pore size distributions). The comparison of carbon dioxide isotherms obtained on prepared samples revealed that their adsorption properties are influenced by the type of mesoporous structure. The SBA-15 silica containing magnesium oxide and promoted by potassium...

1 Title: Interaction of group III and IV metals with Si(100) surface in temperature range from 20 to 800 K Author: Martin Setvín Department: Departement of Surface and Plasma Science Supervisor of the doctoral thesis: Doc. RNDr. Ivan Ošt'ádal CSc. Abstract: Interaction of group III and IV metals with Si(100) surface was studied by STM (Scanning Tunneling Microscopy) and AFM (Atomic Force Microscopy) in temperature range from 20 to 800 K. Adsorption and hopping of single metal adatoms on Si(100)-c(4×2) reconstruction can be observed by STM at low temperatures. Activation energies and frequency prefactors for hopping of single indium atoms were measured by two meth- ods - direct STM measurement at low temperature and Kinetic Monte Carlo simulations of layer growth at room temperature. Group III and IV atoms self-assemble into single atom wide chains on Si(100) surface at about room temperature. Atomic and electronic structure of the chains was investi- gated by means of STM and dynamic non-contact AFM. Keywords: Si(100), STM, AFM, adsorption, diffusion

Due to its toxicity, the Cr(VI) is known as a substance with negative effects on the environment. Understanding of Cr mobility, speciation and its toxicity helps to prevent negative impacts of this contaminant in soils, natural waters and atmosphere. This diploma thesis deals with a mechanism of Cr(VI) adsorption on to mixture of selected soil minerals as quartz, kaolinite and ferrihydrite based on mineralogical and chemical composition of the real contaminated soil. Main goal of diploma thesis is to test the selected surface complexation model, the DLM (diffuse layer model), which could be able to capture the process of Cr(VI) adsorption in natural heterogenic systems like soils. Component additivity approach (CA) was tested. The adsorption experiments were performed with three different concentrations of Cr(VI) (10-4, 10-5, 10-6) as a function of pH at different ionic strengths. Obtained data were used for modelling of adsorption edges and for DLM testing. Results confirmed, that Cr(VI) adsorption in synthetic mixture of enlarged soil minerals, is controlled mainly by presence of Fe-(oxy)hydroxides. The mechanistic surface complexation models used for modelling of Cr(VI) adsorption onto synthetic mineral mixtures, based on real mixed ratios of representative mineral phases in soils, can be useful for prediction of processes responsible for transport and retention of the Cr(VI) in soils.

In this work I briefly described the basic ideas of density functional theory (DFT) for calculations of an electronic structure of molecules, solids and surfaces. I also summarized the fundamentals of DFT based Fireball code that was used for calculations of the atomic and electronic structures of several models. Fur- ther I described theory of scanning tunnelling microscopy (STM) and mentioned some approaches of simulating STM maps by means of results of DFT calcula- tions. The studied models were reconstructions of a Si (111) surface, namely the 7×7, 2×1 Pandey chain and reconstructions with periodicity √ 3 × √ 3, where finding proper atomic structure, fitting to a new experimental observations, was required. I compared energetic favourableness of the reconstructions. I also stud- ied an adsorption of benzene on 7×7. I have analysed the atomic and electronic structure of all the models and made STM simulations using STM code. I com- pared the results with experimental STM maps in literature and with results of the STM experiments made by RNDr. Pavel Kocán, Ph.D. (reconstruction v √ 3 × √ 3) and by Prof. Alastair McLean (benzene on 7×7). Probable model of observed metastable reconstruction √ 3 × √ 3 was found. The proof that benzene chamisorbate in so called di-σ-bridge position was also made. 1

New procedures for preparation of polyacetylenes with highly luminescent naphthalimide groups that might be potentially utilized in optoelectronics and sensors are developed within the framework of present doctoral thesis. The procedures provide luminescent a) linear polyacetylenes that can be processed from solutions, and b) mesoporous network polyacetylenes with high pore volume. Two paths to soluble polyacetylenes are used: (i) copolymerization of ethynyl- functionalized naphthalimide (monomer PN) and a monoethynyl aromate catalyzed with [Rh(nbd)acac], and (ii) modification of poly(disubstituted acetylene)s carrying -chloroalkyl pendants involving the exchange of chlorine atoms for azido groups and subsequent "click"- reaction of Huisgen type of azido groups with ethynyl groups of PN. The PN does not homopolymerize but copolymerizes with ethynylaromates. The highest possible molar fraction of the PN units in copolymers is of 0.5, which suggests the absence of PN dyads or longer sequences in copolymers and the alternating arrangement of PN units in the copolymers of the composition of 0.5. Surprisingly, ethynylarenes that give insoluble homopolymers gave soluble copolymers with PN. The modification procedure requires knowledge on the effect of the monomer structure symmetry and substituent...

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.

To obtain accurate adsorption energies of molecules on surfaces is a challenging task as the methods with sufficient accuracy are too computationally demanding to be applied to the systems of interest. Embedding theories provide a natural remedy: focus the computation on a small region and incorporate the effects of the environment. In this thesis, embedding schemes and the response of many-electron systems to an adsorbed impurity are investigated. To this end, two approaches are used: tight-binding and ab initio. In the tight-binding method, the Green's function formalism is studied and explicit expressions for Green's functions of various one- and two-dimensional models are obtained. Using this formalism, we study qualitatively the local density of states and adsorption energies. In the second part of this thesis, state-of-the-art ab initio methods are employed to study convergence of the subtractive embedding scheme for adsorption energies of small closed-shell systems on two-dimensional graphene and hexagonal boron nitride. The efficiency and applicability of the scheme are assessed for neon and hydrogen fluoride as adsorbates. We found that the studied embedding method works better for neon compared to hydrogen fluoride, which may be explained by the use of a two-body dispersion correction.

In this work we present the results of the analysis of the surface structures and absorption properties with respect to the CO and O2 molecules of the Sn/Rh and Rh/SnO2 model systems. In the part dedicated to the Sn structures on Rh surfaces with two different orientations - Rh(110) and Rh(111) - we have investigated the development of the core electron levels and valence band during the development of surface reconstructions and absorption of CO molecules. The surface reconstructions of the Sn/Rh(110) systems were studied for the first time. Difference in behaviour w.r.t. Sn/Rh(111) was observed and explanation offered. Finally, on in-situ prepared epitaxial SnO2 layers, the surface reconstruction (4×1) was observed. The CO adsorp- tion properties of Rh on polycrystalline and epitaxial SnO2 layers were also studied and difference in behaviour explained.