Due to industrialization and population growth, environmental contamination caused by organic pollutants is becoming an increasing problem worldwide. Environmental pollution on a global scale, particularly water pollution, has drawn scientists’ attention to the vital need for environmentally clean and friendly chemical processes. The demand for higher quality water has increased due to population growth, more stringent health regulations and economic development. Untreated wastewater contains a variety of organic compounds with variable toxicities as well as carcinogenic and mutagenic properties. Most contaminants in wastewater contain aromatic rings, which are generally resistant to chemicals, photochemicals and biological degradation.These compounds are very persistent in the environment and have a high potential to negatively affect human health and the ecosystem. Therefore, the removal or degradation of hazardous material and contaminants from wastewater is a significant global challenge. This thesis reported on the synthesis of titanium dioxide by using a peroxo method. This synthesis was done in the presence of a number of fluoride-containing surfacemodifying agents to determine the effects of these agents on particle growth, shape and crystallinity. Further, studies were carried out to investigate the modification of F-modified TiO2 with the deposition of Au colloids and an Au9 cluster. A different deposition method is employed in the synthesis of the TiO2-Au materials to gain a catalyst with the highest photocatalytic activity. The performance of the catalyst was further investigated through pre-treatment and post-treatment of the materials. Finally, several of the synthesised materials were trialled as photocatalysts using industrial dye Reactive Blue 19 (RB19) as an organic pollutant.

The performance of supported palladium catalysts that had been modified with triphenyl phosphine, diphenyl sulfide and triphenyl amine was compared to unmodified Pd/TiO2 catalysts. It was found that the selectivity was superior to the unmodified catalysts with or without the use of carbon monoxide as a modifier. Ethylene selectivities in excess of 70 % at conversion levels greater than 80% were observed on the modified catalysts under conditions of excess hydrogen which compares extremely well with other catalysts found in the literature. The modifier was found to significantly reduce the number of high energy sites on the surface on the palladium, thereby significantly hindering ethylene hydrogenation but not affecting acetylene hydrogenation. The simple preparation of these catalysts together with the simplicity added by not having to use carbon monoxide or limited hydrogen promises a viable alternative strategy for commercial catalysis.

A monokinetic beam of neutrons (0.07 e.v.) has been scattered by a gas, and the angular dependence of scattering measured over the range 0° to 90°. This isbelieved to be the first measurement of neutrons diffracted by gas molecules. The experiments were performed with a modified neutron crystal spectrometer using a beam of neutronsfrom the Chalk River pile. The gases studied, CO2 and O2, were at room temperature and approximately 60 atmospheres pressure. Observed intensity distributions are compared with calculated patterns. The latter are based on classical interference theory, so take no account of inelasticscattering. Good angular agreement of interference peaks is found for both gases. Good relative intensity agreement is found for 02, but the measured intensity for CO2 falls below thecalculated curve at small angles. A possible reason for this is given.

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Thesis (Ph. D.)--Virginia Polytechnic Institute, 1942. / Vita. Includes bibliographical references. Also available via the Internet.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 100-104).

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 6 uppsatser.

Thesis (M.Sc.) --University of Adelaide, 1951. / Typewr. copy.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 49-54). Also available via the Internet.