No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1979. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Many studies have demonstrated that sewage treatment plants do not efficiently degrade pharmaceuticals such as antibiotics, hormones, and analgesics. Ozonation has been identified as a promising technique to degrade those compounds. A series of experiments was used to evaluate the impact of three parameters on the efficiency and kinetics of degradation of sulfamethoxazole, an antibiotic, by ozonation. An ozone reactor was designed to perform experiments. Analytical techniques, based on liquid and gas chromatography and mass spectrometry, were developed to measure concentrations of sulfamethoxazole and identify degradation products. / It was shown that the rate constant and the degradation efficiency are greater when the initial concentration of sulfamethoxazole is lower; the presence of other contaminants in solution decreases the percentage of degradation observed, and the concentration of hydrogen peroxide, used as catalyst, must be well adjusted since an inappropriate concentration hinders the reaction. Finally, the analysis of ozonated samples allowed the identification of degradation products and resulted in a proposed degradation mechanism.

No description available.

No description available.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 54-58). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 54-58). Also available on the Internet.

D.Sc. (Chemistry) / Two different projects with the central theme of oxidation are discussed, namely the ozonation of saturated hydrocarbons and the total synthesis of an unusual steroid glycoside. The oxidation of saturated hydrocarbons by ozone with the so-called dry ozonation technique was investigated. This study led to the development of improved procedures in which the rate, yield and selectivity of the reaction between ozone and various saturated substrates could be controlled. Subsequently the dry ozonation of a broadspectrum of long straight chain saturated hydrocarbons, including waxes, was investigated. Reaction with these highly unreactive compounds gave almost exclusively ketones as products in high yields. The average amount of keto functionalities in the products is dependent on the reaction conditions as well as the chain length of the substrate. Therefore, a reliable method has been developed for the selective oxidation of straight chain saturated hydrocarbons, a process that is of great chemical, industrial as well as commercial importance. The dry ozonation of various straight chain monoketo compounds was also studied. Poliketo compounds are mainly formed in these reactions. This investigation showed that keto functionalities in the substrates exert a deactivating effect on neighbouring methylene groups, so that oxidations do not take place at these positions. Therefore, it was possible to predict the product distribution formed during the dry ozonation of shorter chain length monoketo compounds (Cg) . An effective synthesis of an unusual steroid glycoside similar to orbicusides A-C, compounds that contain extraordinary carbohydrate and A-ring moieties, was developed. Oxidation reactions played a prominent role in this reaction sequence. A substantial effort was also directed towards obtaining the correct stereochemistry at the various stereocentres of the carbohydrate moiety. This facilitated ring closure to a final product that contained carbohydrate and A-ring moieties similar to orbicusides A-C. As a result of this work, a method was developed for the introduction of a vicinal cis-diol on the sterically hindered face of an alkene. This method is especially suited for substrates where acid labile functional groups are present.

The effect of ozone on the inactivation of two Gram-negative strains (Escherichia coli and Pseudomonas aeruginosa) and one Gram-positive endospore (Bacillus subtilis) bacteria, often present in water and the cause of some waterborne diseases was investigated as a function of ozone concentration and ozonation duration. Ozone was generated in situ using corona discharge methods where the ozone concentration ranged from 0.906 - 4.724 mg/L and the inactivation of the three microbes followed pseudo-first order kinetics with respect to the microbes. Three microbes were cultured and the influence of temperature and pH of the aqueous systems on the ozone initiated inactivation rate of the three microbes was also investigated. This study reports that molecular ozone is more effective than hydroxyl radicals initiated by the ozone chain reactions. Two suggested mechanisms for the antimicrobial effectiveness of ozone in water systems from the literature is discussed. The study also found that ozonation significantly decreased the Biological Oxygen Demand (BOD) value of natural water. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2008.

Trihalomethanes such as chloroform, dichlorobromomethane, dibromochloromethane, and bromoform are formed when natural water is chlorinated in water treatment. This investigation explores the use of ozone to remove organic precursors from natural water, thus decreasing trihalomethane formation potential. The data suggest a mechanism involving formation of secondary precursors after prolonged contact with ozone, suggesting that trihalomethane precursors may be minimized by using low doses of ozone and short contact time.