Master of Science (MS), Ohio University, 2016, Chemical Engineering (Engineering and Technology)

The U.S. oil/gas industry generates over 21 billion barrels of produced water annually. This wastewater stream contains a host of components including suspended solids, dissolved solids, and hydrocarbons. This waste stream represents a significant beneficial resource if reused to offset other water consumption demands. However, many beneficial reuse applications have strict hydrocarbon limits. Oxidation of hydrocarbons in supercritical water media provides an effective removal technique allowing wastewater reuse. In order to quickly and effectively remove hydrocarbons in supercritical water a heterogeneous catalyst is needed. In this study, an MnO2 catalyst on a TiO2 support was synthesized and evaluated for removal of phenol in supercritical water. Synthesized catalysts were characterized using temperature programmed reduction, pulse chemisorptions and X-ray powder diffraction. Catalyst activity for phenol conversion was evaluated in a continuous packed bed reactor at supercritical water conditions, while analyzing vapor and liquid products. Evaluated process variables included free O2 concentration and the catalyst Mn loading. Both variables had positive effects on phenol conversion. The process reached complete destruction of phenol at an O2 level of 500% of the stoichiometric O2 for complete oxidation. Increase in catalyst Mn loading increased its active sites concentration enhancing the contribution of heterogeneous reaction kinetics for phenol supercritical water oxidation (SCWO); however a saturation limit appeared to be reached as Mn loading is further increased. A part of the Mn composition appeared to be unable to create active sites on the catalyst due to interactions with TiO2. A phenol conversion of 70% was reached at 12% (w/w) Mn in the catalyst with 100% excess O2.

Committee: Jason Trembly PhD (Advisor); David Young PhD (Committee Member); Marc Singer PhD (Committee Member); Natalie Kruse PhD (Committee Member) Subjects: Chemical Engineering; Energy; Engineering; Environmental Engineering

Master of Science, University of Akron, 2006, Physics

Dielectric materials have been widely used in electronic industry. Recently an oxide ceramic CaCu3Ti4O12 (denoted as CCTO) is reported to be very promising because it possesses a very high dielectric constant. However, further research on its dielectric properties indicates that this material has a high dielectric loss, which seriously blocks its practical application. In this work, pure CCTO ceramic, and two series of CCTO derivatives, i.e., “CCTO + CaTiO3” and “CCTO + MnO2” ceramics were prepared, and their phase assemblies, structure, dielectric properties, and conducting properties are studied. The relaxation mechanism was investigated for CCTO and its derivatives. It is for the first time revealed that the relaxation time follows the Vogel-Fulcher relation instead of the Arrhenius relation.

Committee: Ang Chen (Advisor) Subjects: