Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 77-78). Also available on the World Wide Web.

A numerical model has been developed, based on an implicit finite difference technique, for the solution of a set of coupled non-linear partial differential equations (based on the Nemst-Planck equation), and linear and non-linear algebraic equations. These equations govern the mass transport and homogeneous chemical reactions in a simplified membrane chlor-alkali cell anolyte compartment. Membrane chlor-alkali cells are used for the industrial production of chlorine and sodium hydroxide, by electrolysis of brine. The model has been developed in an attempt to gain insight into the very localised chemistry which occurs in the hydrodynamic boundary layers within the electrolyser; chemistry which is strongly suspected to have a significant influence on the bulk chemistry, particularly on the homogeneous reactions leading to loss of chlorine through the formation of thermodynamically stable unwanted by-products such as the chlorate ion. These effects are very difficult to measure experimentally, making modelling the most attractive option. A set of experiments have been performed on laboratory scale electrolysers, in an attempt to characterise the cell chemistry, and produce data for model validation. Results are presented from the model demonstrating that the numerical approach adopted produces stable and physically plausible results under a range of operating conditions. It also demonstrates that the chemistry in both the anode and membrane hydrodynamic boundary layers differs significantly from that in the bulk. The experimental work has provided valuable insight into the mechanism of the loss reactions. Results of the experimental work are also compared with the results of the modelling.

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The nature of the surface reaction of chlorine with activated carbon was investigated in the following way. A measured amount of chlorine was admitted to outgassed charcoal and pressure and temperature readings taken over the pressure range 10⁻⁵ - 10⁻² mm. Chlorine was removed in increments until a series of isosteres were obtained in the temperature range -183° to 1180°C. From these functions desorption isobars and heats of adsorption were calculated. Conclusions were drawn from the values of these as to the nature of the surface reaction of the chlorine and activated carbon. / Science, Faculty of / Chemistry, Department of / Graduate

The production of vibrationally excited oxygen, O*₂, following the isothermal flash photolysis of C10₂, C1₂O and of the C10 free radical has shown to be due to the reactions of oxygen atom with C10₂ and C10 (1, 2). In both reactions, the energy, distribution in the products is markedly non-equilibrated with a large fraction of the energy liberated in the form of vibrational excitation of the oxygen molecule. The highest level of O*₂ produced corresponds to the exothermicity of the reactions. The rate constants for the production of O*₂ in levels v'’ = 6 ➛ v’’ = 13 are approximately equal. The relaxation of 0*₂ by C10₂, C10 and by C1 and 0 atoms has been studied and the exceptional efficiency of the atoms demonstrated. The rate constant for the bimolecular reaction of C10 radicals (10) was measured using C10₂, C1₂/0₂, C1₂0, C1₂0/C1₂ as sources of the radicals. The constancy of the value of 2.7 ± 0.3 x 10⁷ 1 mole⁻¹ sec⁻¹ obtained from all systems contrasts with the literature values of 6.2 x 10⁷ 1 mole⁻¹ sec⁻¹, 4.8 x 10⁷ 1 mole⁻¹ sec⁻¹ and 2.4 x 10⁷ 1 mole⁻¹ sec⁻¹, obtained from the first three systems. The chlorine and bromine photosensitised decomposition of C10₂ and C1₂0 have been studied and the extinction coefficient of C10 and BrO free radicals measured. Mechanisms have been proposed for all systems and all relevant rate constants have been measured. The results are listed below. [formulas omitted] / Science, Faculty of / Chemistry, Department of / Graduate

The kinetics of the recombination of chlorine atoms has been studied in a fast flow system in the pressure range 0.2 to 2.0 mm Hg. The gas phase recombination was found to follow the reaction CI + CI + M→C1₂ + M (1) with (formula omitted). Rate constants were determined for He and C1₂ as third bodies in the reaction where k₁C1₂ = 2.45 x 10¹⁶cm⁶moles⁻²sec⁻¹ and k₁He = 0.3x l0¹⁶cm⁶moles⁻²sec ⁻¹ Concurrent with this reaction was a surface recombination which may be written C1 + wall → ½C1₂ + wall (26) having a surface recombination coefficient ɤ = 6.81 x 10⁻⁵, calculated from k₂₆ = 3.9 sec⁻¹. No low pressure change in the kinetic order could be detected under the experimental conditions used. The emission accompanying the recombination was found to be a band spectrum of a (formula omitted) transition. The emission decayed according to the relation (formula omitted) indicating that the (formula omitted) state is formed in some atom recombination process. / Science, Faculty of / Chemistry, Department of / Graduate

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This research is concerned specifically with the growth of two selected algae found surviving in chlorinated water in outdoor swimming pools. Unialgal cultures were used to determine the free chlorine residuals that these algae were able to tolerate.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 157-164).

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 168-177).