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Influence of humic acids on the corrosion behavior of low carbon steel
Horák, Tomáš ; Buchtík, Martin (referee) ; Doskočil, Leoš (advisor)
This diploma thesis deals with influence of humic acid from lignite on corrosion behavior of low carbon steel S235JR in the environment of 0,1 M NaCl at three diffrent pH values (5, 7 and 9). Humic acid was fractionated into three soluable fractions at pH 5, 7 and 9. Corrosion behavior was studied by potentiodynamic polarization, electrochemical impedance spectroscopy and immersion tests. Surface analysis of low carbon steel was carried out before and after corrosion tests as well as analysis of corrosion medium. The results show that humic acid has negative effect on corrosion of low carbon steel in comparison with 0,1 M NaCl solution, because in presence of humic acid, the corrosion rate is higher. The negative effect was attributed to the formation of complexes of humic acid with released iron ions. The main corrosion product on the surface of low carbon steel after exposure to the 0,1 M NaCl was magnetite. Presence of humic acid in 0,1 M NaCl caused formation of lepidocrocite as main corrosion product. Potencial mechanism that is trying to clarify the formation of corrosion products and influence of humic acid on corrosion behavior is discussed in this thesis.
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Study of properties of electrolytically modified NaCl solutions.
Brázda, Lukáš ; Mika, Otakar Jiří (referee) ; Mašek, Ivan (advisor)
This work concentrates on the study of properties of NaCl solutions, prepared by electrolysis and their using for disinfection of water. Then it is focused on reporting on possibality for corrosin of metals, whice are used in water distribution. For study was used 0,25 mol/l, 0,1 mol/l, 0,05 mol/l NaCl solutions and input direct-current voltage for electrolysis was 6V a 12 V. During the electrolysis pH and conducitivity were measured. After the end of electrolysis free active chlorine and chlorides were determined on the time. For electrolysis was used diaphragm.
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Determination of chlorides in pharmaceutical substances
Čutová, Michaela ; Pharm.Dr.Tomáš Schenk (referee) ; Omelková, Jiřina (advisor)
The topic of this bachelor work is a validation of the method for „Determination of chlorides in pharmaceutical substance“ is made in a form of validation of an analythical method. This titration method with potentiometric indication was developed in a company Sicor and it is used for determination of the residual chlorides volume in the substance called Pemetrexed. Validation is a process which assess suitability of a given analythic system for gaining relevant data (results). Validation constists of four tests: precision, reproducibility, lineraity and test of solution stability, although the test of reproducibility was realized in other laboratory (QC). For determnination of the chlorides was applyed titrator 716 DMS Titrino with argent combined electrode. For a data evaluation were used software tiamo 1.1 and MS Excel.
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Determination of chlorides in biological material and its significance
KOROUSOVÁ, Iveta
Significant changes in concentration of minerals and acid-base balance can be expected in critically ill patients. Chlorides are one of the analytes to be determined. Currently the measurement of chlorides in serum and blood samples is predominantly performed by potentiometry with an ion-selective chloride electrode. During the determination of chloride concentration some interferences by other substances in the blood can be found. The most significant of them are interferences of bicarbonates. Since last year, 260 blood samples of patients from the Intensive Care Unit of the 1st Department of Medicine in Faculty Hospital in Pilsen were collected in the Institute of Clinical Biochemistry and Hematology in Faculty Hospital in Pilsen. Concentration of chlorides in biological material was determined by the commonly used methods. The results were compared and the possible interferences of bicarbonates were explained. Basic method for determination of chlorides is coulometry where bicarbonates don´t interfere. During the measurement of chlorides on the ABL835 FLEX analyser (Radiometer) no interferences were detected. During the measurement of chlorides on the GEM Premier 4000 (Instrumentation Laboratory) and Cobas 8000 analysers (Roche) interferences of bicarbonates were found. Nevertheless, the effect of bicarbonates was not clinically significant in interpreting the results.
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Influence of humic acids on the corrosion behavior of low carbon steel
Horák, Tomáš ; Buchtík, Martin (referee) ; Doskočil, Leoš (advisor)
This diploma thesis deals with influence of humic acid from lignite on corrosion behavior of low carbon steel S235JR in the environment of 0,1 M NaCl at three diffrent pH values (5, 7 and 9). Humic acid was fractionated into three soluable fractions at pH 5, 7 and 9. Corrosion behavior was studied by potentiodynamic polarization, electrochemical impedance spectroscopy and immersion tests. Surface analysis of low carbon steel was carried out before and after corrosion tests as well as analysis of corrosion medium. The results show that humic acid has negative effect on corrosion of low carbon steel in comparison with 0,1 M NaCl solution, because in presence of humic acid, the corrosion rate is higher. The negative effect was attributed to the formation of complexes of humic acid with released iron ions. The main corrosion product on the surface of low carbon steel after exposure to the 0,1 M NaCl was magnetite. Presence of humic acid in 0,1 M NaCl caused formation of lepidocrocite as main corrosion product. Potencial mechanism that is trying to clarify the formation of corrosion products and influence of humic acid on corrosion behavior is discussed in this thesis.
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Determination of chlorides in pharmaceutical substances
Čutová, Michaela ; Pharm.Dr.Tomáš Schenk (referee) ; Omelková, Jiřina (advisor)
The topic of this bachelor work is a validation of the method for „Determination of chlorides in pharmaceutical substance“ is made in a form of validation of an analythical method. This titration method with potentiometric indication was developed in a company Sicor and it is used for determination of the residual chlorides volume in the substance called Pemetrexed. Validation is a process which assess suitability of a given analythic system for gaining relevant data (results). Validation constists of four tests: precision, reproducibility, lineraity and test of solution stability, although the test of reproducibility was realized in other laboratory (QC). For determnination of the chlorides was applyed titrator 716 DMS Titrino with argent combined electrode. For a data evaluation were used software tiamo 1.1 and MS Excel.
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Study of properties of electrolytically modified NaCl solutions.
Brázda, Lukáš ; Mika, Otakar Jiří (referee) ; Mašek, Ivan (advisor)
This work concentrates on the study of properties of NaCl solutions, prepared by electrolysis and their using for disinfection of water. Then it is focused on reporting on possibality for corrosin of metals, whice are used in water distribution. For study was used 0,25 mol/l, 0,1 mol/l, 0,05 mol/l NaCl solutions and input direct-current voltage for electrolysis was 6V a 12 V. During the electrolysis pH and conducitivity were measured. After the end of electrolysis free active chlorine and chlorides were determined on the time. For electrolysis was used diaphragm.
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