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Chemical and thermal stability of humic complexes
Nováková, Tereza ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
The aim of this diploma thesis was the study of relation between chemical and thermal stability of complexes of humic acids with heavy metals, namely nickel, cobalt and copper. Complexes were prepared with metal solutions of three different initial concentrations. Through UV-VIS spectrophotometry were determined adsorbed amounts of incorporated metal ions in the structure of humic acid; it was affirmed that amount of bounded metal ions increases with increasing initial concentration. Chemical stability was determined as an amount of released metal ions, two of extraction agents were used (solution of MgCl2 and HCl), total bounded amount was distribute into three different fractions; residual fraction, strongly bound fraction and mobile and ion-exchangeable fraction. Changes that occured in the structure of humic acids after complexation and extraction were investigated by FT-IR spectrometry. Thermo-oxidative stability was tested through thermogravimetric analysis (TGA) and differential scanning calorimetry. The results of this diploma thesis has showed comparision of complexes of two different humic acids. They have confirmed an impact of each metal ion on thermo-oxidative stability of humic acids. The relation between chemical and thermal stability was compared through correlation of data obtained by these methods.
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Stability of humic substances
Nováková, Šárka ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
This bachelor´s thesis is focused on the study of stability of humic acid. Thesis is divided in two parts, the first part is theoretical. In the theoretical part is dealing with the structure, property and point of humic acid and in the experimental part is dealing with stability of humic acid. The objective of this thesis was to investigate the effect of the extraction agents on stability of humic acid. 1M HCl, 1M MgCl2 and MiliQ water was used like extraction agents. Thermo-oxidative stability was tested trough thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Changes of humic acid that occured after extraction were investigated by FT-IR spektrometry and elementary analysis. The results of the measuring were compared with original humic acid.
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METHODS OF POLY-3-HYDROXYBUTYRATE EXTRACTION AND THEIR OPTIMIZATION
Pospíšilová, Aneta ; Plachá,, Daniela (referee) ; Kowalczuk, Marek (referee) ; Přikryl, Radek (advisor)
Poly-3-hydroxybutyrát (PHB) je biolodegradovatelný a biokompatibilní termoplastický polymer se širokou škálou potenciálních aplikací. Výroba PHB typicky zahrnuje fermentaci obnovitelných surovin bakteriemi. Získávání PHB z bakterií je však často náročné a neefektivní. V této práci jsou zkoumány a porovnány různé metody pro získání PHB, včetně digesce, mechanického rozrušení a extrakce. Jsou diskutovány různé optimalizační strategie, které lze použít ke zlepšení účinnosti izolace PHB. Experimentální a výsledková část popisuje snahy o zlepšení metod izolace, zejména kyselé a mýdlové digesce, které byly vybrány jako potenciálně ekonomické, bezpečné a šetrné k životnímu prostředí. Společně s našimi průmyslovými partnery jsme tyto technologie úspěšně otestovali v čtvrtprovozním měřítku a plánuje se další vývoj. Řešily se také možné aplikace a komercializace PHB. Bylo zjištěno, že PHB může nahradit některé mikroplasty v kosmetice a že toto úsilí má potenciál, protože přítomnost mikroplastů v běžných výrobcích je stále vysoká a na úrovni Evropské unie je plánován jejich zákaz. Dále byla studována tepelná stabilita PHB v závislosti na metodě získávání a byly vyvinuty dvě stabilizační metody, které umožnily použít PHB získaný digescí za použití mýdla v materiálových aplikacích.
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Stability of humic substances
Nováková, Šárka ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
This bachelor´s thesis is focused on the study of stability of humic acid. Thesis is divided in two parts, the first part is theoretical. In the theoretical part is dealing with the structure, property and point of humic acid and in the experimental part is dealing with stability of humic acid. The objective of this thesis was to investigate the effect of the extraction agents on stability of humic acid. 1M HCl, 1M MgCl2 and MiliQ water was used like extraction agents. Thermo-oxidative stability was tested trough thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Changes of humic acid that occured after extraction were investigated by FT-IR spektrometry and elementary analysis. The results of the measuring were compared with original humic acid.
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Chemical and thermal stability of humic complexes
Nováková, Tereza ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
The aim of this diploma thesis was the study of relation between chemical and thermal stability of complexes of humic acids with heavy metals, namely nickel, cobalt and copper. Complexes were prepared with metal solutions of three different initial concentrations. Through UV-VIS spectrophotometry were determined adsorbed amounts of incorporated metal ions in the structure of humic acid; it was affirmed that amount of bounded metal ions increases with increasing initial concentration. Chemical stability was determined as an amount of released metal ions, two of extraction agents were used (solution of MgCl2 and HCl), total bounded amount was distribute into three different fractions; residual fraction, strongly bound fraction and mobile and ion-exchangeable fraction. Changes that occured in the structure of humic acids after complexation and extraction were investigated by FT-IR spectrometry. Thermo-oxidative stability was tested through thermogravimetric analysis (TGA) and differential scanning calorimetry. The results of this diploma thesis has showed comparision of complexes of two different humic acids. They have confirmed an impact of each metal ion on thermo-oxidative stability of humic acids. The relation between chemical and thermal stability was compared through correlation of data obtained by these methods.
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