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Simultaneous online determination of nitric acid and nitrates in ambient air
Alexa, Lukáš ; Čmelíková, D. ; Cigánková, Hana ; Mikuška, Pavel
The innovated method for the simultaneous online determination of HNO3/NO3- in ambient air was developed. Due to high sensitivity of CLD (LOD = 5.1 nM in water solution, 3 s/n) no preconcentration method is required. The online methods were compared with the results obtained with the offline method based on sampling using filters and dry denuders (DD) covered by 0.5% NaF with subsequent analysis by ion chromatography (model ICS-2100, Dionex, USA) and capillary electrophoresis (model Agilent 7100, Agilent Technologies, USA).
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Water quality analysis using colorimetry
Kovaldová, Eliška ; Zumberg, Inna (referee) ; Čmiel, Vratislav (advisor)
This bachelor's thesis deals with the analysis of water quality using colorimetry. Part of the work is an introduction to the physical and chemical parameters of water, as well as optical methods, which include photometry, spectrophotometry and colorimetry, and an introduction to regression analysis. These methods and analysis are followed by a practical part by measuring pH, nitrate and water hardness using a spectrophotometer and an AS7262 visible light sensor with a SparkFun development board. At the end of the work there is a comparison of absorption spectra, calibration curves and linear regression parameters of both methods.
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Study of decontamination effects of plasma and plasma activated water
Kovaříková, Kateřina ; Krouská, Jitka (referee) ; Kozáková, Zdenka (advisor)
The theoretical part of this Diploma’s thesis describes the use of plasma in decontamination processes. The experimental part of the thesis focuses on the preparation and characterization of model samples of organic dyes by appropriate analytical methods. The model samples were treated by direct exposure to plasma or plasma activated water. For both treatments, two different plasma sources were used - a dielectric barrier discharge in an ozonizer with subsequent bubbling of its gaseous products into the solution, and a microwave plasma jet applied to the liquid surface. The aim of the work was to evaluate the decontamination rate of the samples and to compare the performance of the different systems.
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Simultaneous determination of ultratrace concentration of nitric acid and nitrates in air using chemiluminescent online analysers
Čmelíková, Dorota ; Řezáčová, Veronika (referee) ; Alexa,, Lukáš (advisor)
The diploma thesis is focused on the development, optimization and real use of a continuous flow analyser for online determination of nitric acid and nitrates in air. The principle of analysis is photolytic conversion of nitrate in solution to peroxynitrite with subsequent detection by chemiluminescence reaction with luminol. The main aim of this thesis was to optimize parameters of analyser followed by practical use for analysis of urban air. The detection limit of gaseous nitric acid was 0,13 g·m3, resp. 0,10 g·m3 for nitrates in aerosol. The measured online concentrations were compared with reference offline analysis. The analysis of urban air was realized in two campaigns (September 2022 and February 2023) at Institute of Analytical Chemistry of CAS in Brno. The apparatus was placed in laboratory on the second floor and samples were collected from the window at Veveří street.
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Start-up phase of a denitrifying sulphur reactor
Marková, Jana ; Hrich, Karel (referee) ; Malá, Jitka (advisor)
The diploma thesis deals with the start-up phase of the denitrification sulfur reactor, which is used to remove nitrogenous substances from water. The main content of this work was the investigation of the influence of various parameters on the progress of the start-up phase with the aim of their optimization. For this research, three column reactors with different operating parameters were developed at the Institute of Chemistry, Brno University of Technology. The reactors were operated throughout the start-up phase, and samples were taken regularly during the run-up phase for subsequent analysis. It was evident from the measurement results that the appropriate setting of the input parameters of the column test, which was the HRT 15 h and a filling ratio of S:CaCO3 1:2, a high removal efficiency of nitrates from the model water exceeding 93% was achieved in just 15 days. Furthermore, it was found that the HRT of 10 h is not sufficient for the course of autotrophic denitrification and caused a prolongation of the start-up phase, which is economically less favorable.
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Quality of selected meat products produced in standard and organic quality
JAROŠOVÁ, Martina
The aim of this Master thesis was to compare the presence of used preservation substances and basic ingredients in meat products made in regular and bio-quality. In practical part of the thesis, a polarization measurement was done with the aim to determine whether there is a quality difference between these two production qualities. The obtained data were subsequently processed and statistically evaluated. The statistical evaluation showed that the basic composition of meat products in regular and bio-quality is basically identical in percentage. Furthermore, the frequency of used preservation additives in different foods was statistically evaluated as well. In conclusion, food products in bio-quality showed 0.7 less additive content compared to regular food product, however, the difference was still weighed as statistically insignificant.
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Vlastnosti povrchových vod v závislosti na charakteru krajinného pokryvu v malém povodí
VONDRÁŠEK, Vít
The present thesis covered statistical evaluation of the effect of the management method and the landscape cover on selected hydrochemical parameters of surface water. To obtain and evaluate the necessary data, a model zone was selected, located in the mountains of Novohradské hory. It consists of the upper and lower sub-basins of the stream of Bedřichovský potok, which is the left-hand tributary of the River Stropnice. The sub-basins differ in how management methods are practised locally. While the upper sub-basin generally consists of forests and permanent grasslands, the lower sub-basin has primarily arable land and, in some part, built-up areas. For this reason, it is possible to compare the two sub-basins and evaluate their effect on the selected parameters of surface water; these involved conductivity, concentration of unsuspended solids, total organic carbon concentration, total nitrogen, nitrate nitrogen and phosphate phosphorus. The results show and support a conclusion that surface waters in the lower sub basin, one that is utilised for agriculture, exhibit higher values of the parameters monitored than surface waters present in the upper sub-basin, one that features forest/grassland vegetation cover. It can be noted that arable land has a reduced retention capacity and is more prone to erosion due to its vegetation cover of lesser size; this is also the reason why it is not able to completely retain the desired substances on the agriculturally managed land. This results in deterioration of individual hydrochemical parameters in surface water, such as conductivity or nitrate nitrogen. The thesis is generally indicative of the importance of vegetation cover for the management of water in the landscape.
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The evaluation of nitrate concentrations in linkage with precipitation and water runoff in particular subcatchments of the Kopaninský stream.
HUDCOVÁ, Ivana
Diploma work deals with evaluation of nitrate concentration on trial on rainfall and runoff on partial profiles of Kopaninsky stream. From chemical point of view nitrates are nitric acid salts (e.g. potassium or soda salts) and forms natural part of vegetable and animal masses (metabolism product). At common concentration is not harmful. Nitrates in bodies they can chemical change on nitrite and then further on nitrosamines (organic matters containing nitrogen in its molecule) with carcinogenic effects. Measuring on monitoring profiles past over fortnightly. Strong seasonal progress of nitrate concentrations is perceptible. Highest nitrate concentrations were measured mostly in spring and lowest concentrations in autumn. Maximum nitrate concentration on whole catchment achieves the value 181 mg.l-1 and minimum nitrate concentration achieves the value 0.5mg.l-1. There is nearly no influence on nitrate concentrations by a rainfall. Mostly nitrate concentrations in this catchment gently heighten or stay the same after rainfall, which witness about the fact, that pollution has areal character. As is the influence of land use on runoff in literature described, wasn't this influence in observed micro catchments proved.
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Comparison of precipitation and discharges in relation to nitrate concentrations in the Jenínský stream catchment.
VRZÁK, Zbyněk
This work deals with comparison of precipitation and discharges in relation to nitrate concentrations in the Jenínský stream. The locality is situated on the east of town Vyšší Brod in the southern part of Bohemia. Since the 80`s this small catchment is research area and in the year 2004 The Faculty of Agriculture has continued in this research in Jenínský stream catchment. The backgrounds for this work are data of hydrological year 2006 which are gained from continuous measuring and scanning in small catchment Jenín. There is a recurrency to generalize the precipitation impact which induce changes of discharges on the closing device in small catchment.
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