Thesis (M.S.)--Wisconsin. / Bibliography; leaves 59-60.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 50-[51]).

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains ix, 90 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 83-87).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 88-117). Also available via the Internet.

The equilibrium Chlorite = Cordierite + Forsterite + Spinel + H₂0 has been experimentally determined with a chlorite of composition Mg₄.₇₅Al₂.₅Si₂.₇₅O₁₀(OH)₈. Brackets have been obtained between 605 and 640° C at 0.5 kb, 644 and 670° C at 1.0 kb and 690 and 704° C at 2.0 kb. These data are not notably displaced from Chernosky's (1974) data for the same equilibrium with a chlorite of clinochlore composition (Mg₅Al₂Si₃O₁₀(OH)₈), however they are more constraining. A thermodynamic analysis of the above data and data on related equilibria included ideal solution models describing compositional variability in cordierite, orthopyroxene and chlorite. The H₂0 content of cordierite was described using a model based on that of Newton and Wood (1979). The hydrous end-member has two moles of H₂0 and the volumes of the end-members are different; this allows the full range of data to be described with one function. Al-content of orthopyroxene was calculated with Gasparik and Newton's (1984) model. Solid solution in chlorite was modelled by choosing the end-members, Mg₆Si₄O₁₀(OH)₈ and Mg₄Al₄Si₂O₁₀(OH)₈, and using ideal configurational entropy to describe the free energy of mixing. Disordering phenomena in cordierite and spinel were accounted for by adding small entropies of disorder to the third law entropies. Linear programming was used to calculate consistent thermochemical properties for all phases considered. Experimental results indicate that the upper thermal stability of Mg-chlorite is affected by only a few degrees for the composition used here. The thermochemical properties derived allow more complete modeling of systems that include chlorite. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Twelve different powdered activated carbons (PACs) were screened under laboratory conditions to determine their performance in the removal of chlorite ions (ClO₂⁻) and in the production of chloride ions (Cl⁻) and chlorate ions (ClO₃⁻) during that removal. All screenings were conducted in reagent water, at pH 7.0 ± 0.2 pH units, with a standard concentration of 20 mg/liter of powdered activated carbon (PAC) added in each case, and with the process and samples protected from light. One set of screening experiments was conducted with both ClO₂⁻ and chlorine added with the PAC, while the other set contained only ClO₂⁻, and PAC. The chlorine and ClO₂⁻ were added to concentration levels which might be expected in disinfection practice in water treatment plants. Periodic samples were drawn as the mixtures were stirred over a 24 hour period. Each sample was analyzed for Cl⁻, ClO₂⁻, and ClO₃⁻ concentrations utilizing ion chromatography. All PACs were found to reduce ClO₂⁻ to Cl, and ClO₃⁻ was never detected when chlorine was absent. The data provided no consistent significant evidence of ClO₃⁻ formation even when chlorine was present. The rate of ClO₂⁻ removal was most rapid in the first two hours of contact, but slowed to rates below 6 percent per hour after 4 hours of contact. Rates of ClO₂⁻ removal varied with PAC type. The overall rate of ClO₂⁻ removal was also slower, with the total percentage of ClO₂⁻ removal less, when chlorine was present in the mixture. / Master of Science