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Influence of content of organic matter and calcium on immobilization of pharmaceuticals in soil
Kotradyová, Viktória ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This thesis aimed to highlight the problem of antibiotics and their presence in nature, particularly tetracycline. High global consumption, limited metabolism in the body and incomplete degradation in wastewater treatment plants represent the reasons why pharmaceuticals have been found in the environment. Their presence might have a negative impact on the natural ecosystem, including humans. Therefore, addressing their behaviour and finding solutions for their removal from nature seems important. The soil itself has a self-cleaning capacity, which may immobilise these pollutants into organic structures to prevent their subsequent migration. The presence of inorganic cations in soil plays an essential role in the sorption process of antibiotics. Calcium ions from the soil with whom the tetracycline forms chelate complexes, should be also taken into account. Regarding the practical part, tetracycline interactions with soil systems were studied in both sorption and desorption experiments. Four soils with different amounts of organic matter and calcium have been examined. Tetracycline was extensively adsorbed to all four soils. Desorption processes showed low efficiency and refer to stable adsorption onto soil. The experimental data were fitted by Freundlich and Langmuir isotherms, where the second mentioned is suitable for three of the four soils. Subsequently, sorption and desorption experiments were conducted in four different pH buffers (3, 5, 7 and 10). The effect of pH on sorption was not significant, however during desorption at lower pH higher desorbed levels of tetracycline were observed. Photodegradation of tetracycline in solution was investigated to determine the rate of degradation of tetracycline on light, where the results indicated that the concentration decreased by 22 % after 29 days compared to the applied concentration. Quantitative analysis was carried out using UV-VIS spectroscopy and liquid chromatography. In addition, the soil spectra of the FTIR were measured to obtain information on the sorption mechanism
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