National Repository of Grey Literature 91 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Removal of emerging contaminants from water by a hybrid membrane-catalytic oxidation process
Bourassi, Mahdi ; Klusoň, Petr (advisor) ; Bendová, Magdalena (referee) ; Granger, Pascal (referee)
Emerging contaminants were detected in different surface waters around the globe. These active molecules affect the environment even at trace concentrations. They are sourced mainly from wastewater treatment plants. These contaminants persist the conventional wastewater treatments and gain their way to the environment. This can cause different complications: bioaccumulation, antibiotic resistance, and environmental degradation. The presented Ph.D. thesis is focused on the treatment of wastewater loaded with persistent pollutants. This thesis aimed to evaluate the membrane separation technology and the catalytic wet air oxidation (CWAO) process to associate them in a hybrid process to address this issue. The first part of the hybrid process is focused on challenges faced with the membrane separation process, mainly fouling and selectivity. This part gathers 6 publications all focused on wastewater treatment with membrane separation. As a starter, the review covers the issue presented by the emerging contaminants and the potential of the membrane process for water recovery. The review highlighted the advantages and challenges (fouling and selectivity) of the membrane process. The chapter about membrane fouling gathers two publications: "Removal of ibuprofen from water by different types of...
Removing of organic dyes from water using polyacrylamide hydrogel nanocomposites
Špalová, Anna ; Klusoň, Petr (advisor) ; Krystyník, Pavel (referee)
The unavailability and pollution of water resources have become significant global challenges. Hydrogels composed of cross-linked polymers have emerged as advanced adsorbents for wastewater treatment, owing to their convenient handling and high efficiency. By incorporating appropriate components into the hydrogel structure, the affinity of a specific pollutant to the hydrogel can be modified. Consequently, the resulting hydrogel nanocomposite can display enhanced adsorption capacity, specific selectivity, and other desirable properties. In this thesis, the efficiency of polyacrylamide hydrogel nanocomposites in the removal of organic dyes from water was investigated. Various composites were synthesized, incorporating graphene, kaolin, and laponite. The composition of these composites varied, employing different ratios of monomer to water and monomer to additive. The physicochemical properties of the synthesized hydrogels and their nanocomposites were examined. It was observed that the nanocomposites displayed reduced water-holding capacity compared to pure polyacrylamide hydrogels. The inclusion of additives led to a decrease in nanocomposite rigidity for graphene, minimal alteration in the case of kaolin, and an increase in rigidity for laponite. The compressibility modulus of the samples ranged...
Priority pharmaceutical micropollutants in the context of the Czech Republic and the Water Framework Directive draft
Stonawski, Eva ; Cajthaml, Tomáš (advisor) ; Klusoň, Petr (referee)
One of the major global environmental problems is the pollution by priority micropollutants. These are substances that can have a negative impact on the environment and human health even at relatively low concentrations. Their identification and subsequent regulation on an international level is essential for prevention of the negative effects of these substances. This thesis focused on the assessment of relevance of the proposal of Water Framework Directive in relation to pharmaceuticals and related substances in the context of the situation in the Czech Republic. The analysed input data comprised of results of data monitoring from the Vltava River Basin and information on the distribution of pharmaceuticals from the State Institute for Drug Control between years 2016 and 2022. The data was collected from two sampling points that are situated right before the confluence with the Elbe River. The average of the concentrations above the limit of quantification (LOQ) and without outliers was considered, thus creating a model considering the maximum contamination load. On the basis of this model and information about individual substances, the relevance of the draft WFD for the Czech Republic was assessed. The result of the monitoring showed that during the monitoring period, none of the NECs of the...
Complex identification of N-methylation reaction products in the synthesis of selected pharmaceuticals
Malíková, Sára ; Klusoň, Petr (advisor) ; Cuřínová, Petra (referee)
This thesis studied the process of the N-alkylation reaction of an ergoline derivative in a flow-through microreactor using phase transfer catalysis, which provides a faster exchange of substances at the phase interface and thus accelerates the reaction. Specifically, this reaction involved the N-methylation of LUME (10--methoxy-dihydrolysergic acid methyl ester) to the product MeLUME (1-methyl 10--methoxydihydrolysergic acid methyl ester). Dimethyl sulfate served as the alkylating agent and tetraethylammonium hydroxide as the phase transfer catalyst. Several side products are formed during this reaction. These are mainly LUME acid, which is formed by hydrolysis of the starting substance LUME, as well as the quaternary ammonium salt of the starting substance and the quaternary ammonium salt of the reaction product (MeLUME), which is formed by quaternization of the ergoline skeleton nitrogen due to used excess of the alkylating agent. The aim of this work was to develop an analytical method for the quantitative determination of the starting substance LUME and the products of the investigated N-alkylation reaction, including the most important side products. For this purpose, it was necessary to selectively prepare the above-mentioned side products and, on this basis, to determine their reaction...
Mixture toxicity of estrogenic endocrine disruptors in samples from the Czech Republic
Černá, Tereza ; Cajthaml, Tomáš (advisor) ; Klusoň, Petr (referee) ; Šváb, Marek (referee)
The environment is contaminated by countless toxic chemicals of mainly anthropogenic origin; therefore, elucidating the impact of chemical mixtures is one of the biggest challenges of current research. Endocrine disruptors (EDs) acting through the oestrogenic nuclear receptor are typical representatives of the mixture toxicity concept of concentration addition, which can be accurately predicted using the latest mathematical models. Oestrogenic activity and oestrogenic EDs have been detected in many matrices across the globe in biologically relevant concentrations; therefore, they are considered a high risk. The presence of synthetic steroids in the aquatic environment in units of ng/l can disrupt the hormonal pathways of individuals and subsequently cause fatal changes in whole populations. However, if the exposure is terminated, the ecosystem will recover in a few years. Wastewater treatment plants (WWTPs) are able to remove a large number of chemicals, including synthetic and natural oestrogenically active compounds; nevertheless, their occurrence in WWTP effluents and in sewage sludges is frequent. Therefore, WWTPs are considered significant sources of agricultural and water ecosystem pollution. This dissertation thesis focuses on the mixture toxicity of oestrogenic EDs and their occurrence in...
Ecotoxicity of herbicidal ionic liquids
Müllerová, Tereza ; Cajthaml, Tomáš (advisor) ; Klusoň, Petr (referee)
Herbicidal ionic liquids (HILs) are organic salts with herbicidal properties. Their anions are usually derived from traditional herbicides, and they are paired with cations of a synthetic or natural origin. Because of their hydrophobic nature and lower volatility, HILs are considered an environmentally friendlier alternative to traditional herbicides, which often persist in the environment, contaminate groundwater and are toxic even to non-targeted organisms. Nevertheless, the scientific research on HILs is mainly focused on their effects on plants. In this thesis, the hormonal activity of selected HILs was tested using human cell lines. In addition, the ecotoxic effect of HILs on soil microorganisms was assessed using the analysis of phospholipid fatty acids (PLFA). To study the ecotoxic effect, two different types of soil were incubated with HILs in a 28-day experiment. The soils were characterized by a different management approach - the soils were treated or untreated with pesticides in the past. The effect of the content of soil organic matter and clay minerals on how HILs interact with soil microorganisms was evaluated. The residual concentrations of HILs were quantified during the soil experiment to assess the effect of the management approach applied in the past on the degradation rate of...
Measurement and toxicity of combustion generated nanoparticles
Sikorová, Jitka ; Topinka, Jan (advisor) ; Klusoň, Petr (referee) ; Bláha, Luděk (referee)
This thesis is focused on nanoparticles produced by internal combustion engines utilized in vehicles. It deals with spatial distribution of nanoparticles within urban areas, impact of alternative fuels usage on particle production and toxicity, and a particle toxicological testing methodology. Monitoring of airborne nanoparticles identified traffic as the main source of airborne nanoparticles in places with heavy traffic load (Prague), as well as in a small city with only local traffic (Čelákovice). Most particles were likely emitted during short episodes of high emissions (e.g. uphill acceleration). During the measurements, high-emission vehicles responsible for a large fraction of the air pollution were also identified. On the other hand, small non-road internal combustion engines, which are not subject to any limit on particle emissions, such as a lawn mower, were operated during the measurement and generated a large number of nanoparticles. The amount and characteristics of the particles produced by combustion depend on the combustion technology and the fuel composition. A large part of the thesis deals with alternative fuels and their effects on the quantity of produced particles and toxicity of organic matter adsorbed on the particles. Hydrotreated vegetable oil (HVO) exhibited the lowest...
Electrocoagulation method for treatment of polluted waters
Krušinová, Zuzana ; Klusoň, Petr (advisor) ; Mašín, Pavel (referee)
Many drinking water treatment facilities face problems with algal organic matter (AOM) due to eutrophication of the environment and frequent occurrence of algal blooms. AOM can cause deterioration of water organoleptic properties, but the main threat is the potential for acting as a precursor of toxic disinfection by-products (DBPs). The presented master thesis deals with the possibility of using electrocoagulation (EC) - an innovative electrochemical method - to remove cellular organic matter (COM) produced by cyanobacteria Microcystis aeruginosa from drinking water. EC is similar to widely used chemical coagulation, the difference is that during EC the coagulant is produced by electrochemical dissolution of an iron or an aluminum electrode. Synthetic water with COM concentration of 5.5 and 8.5 mg/L of TOC was used for the experiments. The target value of conductivity (4.5 mS/cm) was reached by addition of NaCl. pH of the solution was adjusted by HCl and NaOH. During some of the experiments, NaHCO3 was added to increase the ANC4.5. The experiments were conducted in a batch mode with a stainless-steel cathode and an aluminum or an iron anode. The coagulant dosage was regulated by applied electric current passing through the electrodes. Flocs were separated by sedimentation and centrifugation. COM...
Microfluidic reactors for chemical synthesis
Jaklová, Natalie ; Klusoň, Petr (advisor) ; Cvak, Ladislav (referee)
The main topic of the Diploma Thesis is the conversion of the batch N-alkylation reaction into a continuous regime. It is the reaction of 10α-methoxydihydrolysergic acid methyl ester to 1-methyl-10α-methoxydihydrolysergic acid methyl ester. It represents one step in the industrial synthesis of Nicergoline, a pharmaceutical used for senile dementia treatment. This methylation reaction is performed in two immiscible liquid phases. Phase-transfer catalysis is used to increase the efficiency of the reaction, which allows the reaction to proceed in the entire volume of the organic solvent, not only at the phase interface. The reaction is rapid, with an exothermic character. The advantages of continuous arrangement are better control of the reaction, increased operational safety due to handling smaller volumes of reaction components, and more intensive removal of heat of the reaction. The Thesis deals with the influence of reaction conditions on the course of the reaction in a microfluidic reactor. The glass microchip reactor was chosen to perform the reaction in a flow arrangement. This reactor could produce up to grams of the product per hour. Several series of experiments were performed on this apparatus. The conversion of the starting material, and selectivities to the product and the side products...
Measurement and toxicity of combustion generated nanoparticles
Sikorová, Jitka ; Topinka, Jan (advisor) ; Klusoň, Petr (referee) ; Bláha, Luděk (referee)
This thesis is focused on nanoparticles produced by internal combustion engines utilized in vehicles. It deals with spatial distribution of nanoparticles within urban areas, impact of alternative fuels usage on particle production and toxicity, and a particle toxicological testing methodology. Monitoring of airborne nanoparticles identified traffic as the main source of airborne nanoparticles in places with heavy traffic load (Prague), as well as in a small city with only local traffic (Čelákovice). Most particles were likely emitted during short episodes of high emissions (e.g. uphill acceleration). During the measurements, high-emission vehicles responsible for a large fraction of the air pollution were also identified. On the other hand, small non-road internal combustion engines, which are not subject to any limit on particle emissions, such as a lawn mower, were operated during the measurement and generated a large number of nanoparticles. The amount and characteristics of the particles produced by combustion depend on the combustion technology and the fuel composition. A large part of the thesis deals with alternative fuels and their effects on the quantity of produced particles and toxicity of organic matter adsorbed on the particles. Hydrotreated vegetable oil (HVO) exhibited the lowest...

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