|
|
Study of ettringite stability depending on external conditions
Pekárková, Jana ; Brauner,, Josef (referee) ; Durica,, Tibor (referee) ; Bílek,, Vlastimil (referee) ; Gazdič, Dominik (advisor)
The doctoral thesis was focused on the study of thermodynamic stability of ettringite. Ettringite was first prepared in two different ways and then exposed in chosen environments. Furthermore, the stability of ettringite in interaction with calciumsilicates was investigated. As ettringite can be formed as a hydration product of fluidized bed fly ash, the properties of Portland fly ash cement in comparison with Portland cement and Portland slag cement were investigated at the end of the thesis.
|
|
|
The use of alternative coagulants in water treatment
Hofmanová, Lucie ; Zelený, Zdeněk (referee) ; Kučera, Tomáš (advisor)
This bachelor's thesis deals with the use of alternative coagulants in water treatment. The first theoretical part mentions types of water treatment for the individual categories of raw water, related laws and ordinances. After that thesis describes the principle, mechanisms of coagulation and factors influencing the process. It analyses the jar test procedure performed within the experimental part of the bachelor's thesis. One chapter deals with polymers and metal coagulants based on aluminium and iron commonly used in water treatment. The chapter includes more detailed description of natural polymers moringa oleifera and chitosan. These two coagulating agents and aluminium sulfate were used in the second experimental part of the bachelor's thesis. Several sets of the jar test were performed in order to investigate the efficiency of chosen coagulants on the removal of turbidity from water. The thesis concludes with a comparison and evaluation of the results. Photos taken during the jar test can also be found at the end of the bachelor's thesis.
|
|
| |
|
|
Effect of active ingredients to the activity of cementing compound with non-alkaline accelerator additive for sprayed concrete.
Závacký, Jakub ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
The bachelor thesis deals with the problems of the sprayed concrete with the focus on usage of the active ingredients with non-alkaline accelerator additive. The theoretical part covers the current level of knowledge of how the active ingredients are used in the sprayed concrete and their influence on the process of hydration. In the experimental part the reactivity of cementing compound with non-alkaline accelerator on the basis of aluminium sulphate were compared in a laboratory when the active ingredients (such as slag, fly-ash and very fine limestone) were used. The cements CEM I 42,5 R, made by different producers were verified on the basis of the setting time and early strength gain using the Vicat needle to examine the mechanical properties after 6 and 24 hours.
|
|
|
Study of ettringite stability depending on external conditions
Pekárková, Jana ; Brauner,, Josef (referee) ; Durica,, Tibor (referee) ; Bílek,, Vlastimil (referee) ; Gazdič, Dominik (advisor)
The doctoral thesis was focused on the study of thermodynamic stability of ettringite. Ettringite was first prepared in two different ways and then exposed in chosen environments. Furthermore, the stability of ettringite in interaction with calciumsilicates was investigated. As ettringite can be formed as a hydration product of fluidized bed fly ash, the properties of Portland fly ash cement in comparison with Portland cement and Portland slag cement were investigated at the end of the thesis.
|
|
|
Influence of preoxidation by potassium permanganate on coagulation of nonproteinaceous compounds produced by alga Chlorella vulgaris
Přech, Jiří ; Pivokonský, Martin (advisor) ; Novotná, Kateřina (referee)
6 Abstract: The presence of phytoplankton and its products (AOM) in source water is a current challenge in water treatment processes. The production of AOM increases with anthropogenic eutrophication of ecosystems. AOM impair the water treatment processes and may form harmful disinfection by-products. The traditional water treatment process is a coagulation, which is very efficient in removing phytoplankton cells, but this is not the case when removing some kinds of AOM. Especially its nonproteinaceous fraction with low molecular weight, which can represent majority of total organic carbon, is removed with very low efficiency. The removal of AOM by coagulation can be enhanced by preoxidation. This thesis examines the influence of preoxidation by potassium permanganate of nonproteinaceous fraction of COM of algae Chlorella vulgaris on its coagulation by aluminium sulphate and polyaluminiumchloride. To compare, solutions with nonproteinaceous COM were coagulated with and without preoxidation by five different doses of permanganate (0,025; 0,05; 0,1; 0,15 a 0,2 mg KMnO4 mg-1 DOC). The doses of permanganate and time need for oxidation (30 minutes) were determined by decreased DOC and permanganate during preoxidation experiments. The maximal DOC removals achieved both with and without preoxidation were 17 %...
|
|
|
Coagulation of non-protein algal organic matter
Lukeš, Jan ; Pivokonský, Martin (advisor) ; Novotná, Kateřina (referee)
The diploma thesis deals with characterizing properties of non-proteinaceous cellular organic matter (COM) of green alga Chlorella vulgaris in connection with its coagulation using aluminium sulphate and polyaluminiumchloride. As a part of this work, interaction mechanisms were also studied. It has been found out that non-proteinaceous COM of Chlorella vulgaris is made up by saccharides (25 % DOCNP, 21 % of dry biomass of non- protein matter) and other unspecified non-protein substances. It has been found out by fractionation of molecular weights that non-protein COM is formed primarily by substances with MW < 3 kDa and substances with MW > 100 kDa. Coagulation by aluminium sulphate taken place in interval pH 5 - 8,5 and coagulation by polyaluminiumchlorid taken place in interval pH 7 - 10 depending on coagulation agent dose. The maximum DOC removals were 17 - 22 % depending on selected coagulation agent, on its dose and pH. Polyaluminiumchloride showed higher DOC removal rates than aluminium sulphate. The highest effectiveness of coagulation was in the area of neutral pH for both agents. In all the coagulation tests the values of residual concentrations of aluminium were higher than the hygienic limit for drinking water (0.2 mg.L-1 ). Primarily high-molecular matter was removed by coagulation and...
|
|
|
The use of alternative coagulants in water treatment
Hofmanová, Lucie ; Zelený, Zdeněk (referee) ; Kučera, Tomáš (advisor)
This bachelor's thesis deals with the use of alternative coagulants in water treatment. The first theoretical part mentions types of water treatment for the individual categories of raw water, related laws and ordinances. After that thesis describes the principle, mechanisms of coagulation and factors influencing the process. It analyses the jar test procedure performed within the experimental part of the bachelor's thesis. One chapter deals with polymers and metal coagulants based on aluminium and iron commonly used in water treatment. The chapter includes more detailed description of natural polymers moringa oleifera and chitosan. These two coagulating agents and aluminium sulfate were used in the second experimental part of the bachelor's thesis. Several sets of the jar test were performed in order to investigate the efficiency of chosen coagulants on the removal of turbidity from water. The thesis concludes with a comparison and evaluation of the results. Photos taken during the jar test can also be found at the end of the bachelor's thesis.
|
|
|
Effect of active ingredients to the activity of cementing compound with non-alkaline accelerator additive for sprayed concrete.
Závacký, Jakub ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
The bachelor thesis deals with the problems of the sprayed concrete with the focus on usage of the active ingredients with non-alkaline accelerator additive. The theoretical part covers the current level of knowledge of how the active ingredients are used in the sprayed concrete and their influence on the process of hydration. In the experimental part the reactivity of cementing compound with non-alkaline accelerator on the basis of aluminium sulphate were compared in a laboratory when the active ingredients (such as slag, fly-ash and very fine limestone) were used. The cements CEM I 42,5 R, made by different producers were verified on the basis of the setting time and early strength gain using the Vicat needle to examine the mechanical properties after 6 and 24 hours.
|
|
| |
guest ::
