Thesis (doctoral)--Universität in Leipzig, 1905.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 133-139).

Effects of commercially available bacterial products were investigated on two common recreational pool contaminants: sunscreen and cyanuric acid (CYA). Microbial products developed by BiOWiSH Technologies, Inc. were tested for enhancing mechanical filtration and water clarification in bench-scale bioreactors, with conditions mimicking those of recreational pool water. Bacterial consortia included proprietary mixes of Bacillus, Lactobacillus and Pseudomonas, and other genera of bacteria. BiOWiSH products are either fermented on a solid substrate consisting of rice bran and soy meal, or they are mixed with a soluble diluent. Twenty-nine BiOWiSH products were tested throughout forty experiments. Experiments were carried out to determine both the efficacy of BiOWiSH products for turbidity reduction and the mechanism by which BiOWiSH removes sunscreen from solution. In trials without mechanical filtration, the only product which showed a reduction in turbidity relative to the control, albeit inconsistently, was the solid substrate version of BiOWiSH Aqua FOGTM (Thai FOG). Experiments on BiOWiSH coupled with mechanical filtration showed a 79% average reduction of turbidity in the first 24 hrs. BiOWiSH products containing solid substrate, both active and abiotic, showed an average turbidity reduction of 90% in the first 24 hrs. In the same timeframe, soluble BiOWiSH products showed a 79% average reduction in turbidity. Thus, the solid v substrate provided an additional 11% reduction in turbidity over soluble products and un-amended mechanical filtration. Through experimentation and scanning electron microscopy, it was concluded that the primary mechanism of clarification by the solid substrate is adsorption of sunscreen to the substrate surface. Further experiments were performed in anaerobic and aerobic environments to determine whether BiOWiSH products can remove cyanuric acid from solution through adsorption or biodegradation. Two measurement methods, turbidimetric and HPLC (high performance liquid chromatography) were used to independently quantify CYA. A reverse-phase HPLC method was developed which utilizes a phosphate buffer and methanol for the separation of cyanuric acid from nitrate and other chemical species. The solid BiOWiSH Aqua FOG product (prod. in Thailand) interfered with the turbidimetric analysis, showing false decreases in CYA. Using HPLC, there was no measureable biodegradation or adsorption of CYA by BiOWiSH products in these bench-scale tests. Significant systematic error in the HPLC analysis prevented conclusive findings; therefore, the ability of BiOWiSH products to reduce CYA from solution remains inconclusive.

Melamine and cyanuric acid are widely used in industry and in scientific research. The mixture of melamine and cyanuric acid can form a hydrogen-bonded network structure which has been used as a surface template in supramolecular chemistry. In this work, the thermochemical properties of melamine and cyanuric acid were characterized using mass spectrometry measurements and computational studies. The proton affinity and the gas-phase acidity were determined with the application of the extended Cooks kinetic method. A triple-quadrupole mass spectrometer equipped with an electrospray source was employed for this study. For melamine, the proton affinity, the gas-phase basicity, and the protonation entropy were determined to be 226.2 ± 2.0 kcal/mol, 218.4 ± 2.0 kcal/mol and 26.2 ± 2.0 cal/mol K, respectively. For cyanuric acid, the deprotonation enthalpy, the gas-phase acidity, and the deprotonation entropy were determined to be 330.7 ± 2.0 kcal/mol, 322.9 ± 2.0 kcal/mol and 26.1 ± 2.0 cal/mol K, respectively. The geometries and energetics of melamine, cyanuric acid, and related molecules/ions were calculated at the B3LYP/6-31+G(d) level of theory. The theoretical proton affinity and deprotonation enthalpy were calculated using the corresponding isodesmic proton transfer reactions. The computationally predicted proton affinity of melamine (225.9 kcal/mol) and gas-phase deprotonation enthalpy of cyanuric acid (328.4 kcal/mol) were in good agreement with the experimental results. Melamine is best represented as the imide-like triazine-triamine form and the triazine nitrogen is more basic than the amino group nitrogen. Cyanuric acid is best represented as the keto-like tautomer and the N-H group is the most likely proton donor. Cyclohexane-based molecular switches have been of great interest in recent years. This work focused on the investigations of the thermochemical properties related to the switching process. A group of cyclohexane-based model compounds were selected for this study. The model compounds included trans -2-aminocyclohexanol, trans -4-aminocyclohexanol and trans -2-dimethylaminocyclohexanol. The proton affinities of the compounds were determined using the extended Cooks kinetic method. The values obtained were 238.5 ± 2.0 kcal/mol ( trans -2-dimethylaminocyclohexanol), 225.5 ± 2.0 kcal/mol ( trans -2-aminocyclohexanol) and 220.4 ± 2.0 kcal/mol ( trans -4-aminocyclohexanol). Various molecular structures related to the model compounds and the switching molecules were calculated at the B3LYP/6-31+G(d) level of theory. The theoretical proton affinities of all the molecules investigated were also calculated at the same level of theory using corresponding isodesmic reactions. The results show that the proton affinities decrease as the relative positions of amino and alcohol groups change from ortho to meta to para . The stronger proton affinity of the ortho isomer may be due to the efficient intramolecular hydrogen bonding in the protonated form. The proton affinity of trans -2-dimethylaminocyclohexanol is stronger than that of trans -2-aminocyclohexanol by about 13 kcal/mol. Substitution of hydrogen atoms by methyl groups at nitrogen promotes the intramolecular hydrogen bonding between the amino group and the hydroxyl group upon protonation. This, in turn, may enhance the proton affinity of methylated molecule. Computational studies also show interesting trends for stabilities and proton affinities of the different structures. These data may be useful as a guide for designing efficient conformational switches.

A facultative anaerobic bacterium that rapidly degrades cyanuric acid (CA) was isolated from sediment of a stream that received industrial waste water effluent. CA decomposition was measured throughout the growth cycle by using a High Performance Liquid Chromatography assay while also measuring the concomitant production of ammonia. This bacterium used CA or cysteine as a major, if not sole, carbon and energy source under anaerobic, but not aerobic conditions in a defined medium. The cell yield was greatly enhanced by the simultaneous presence of cysteine and CA in the medium. Cysteine was preferentially used rather than CA early in the growth cycle, but all the CA was used without an apparent lag after the cysteine was metabolized. Atrazine was also degraded by this bacterium under anaerobic conditions in a defined medium. / Master of Science

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