Abstract Biological oxidation of methane is and important constraint on the emission of this gas from areas, such as landfills to the atmosphere. We studied the effect of covering soils on methane emission in landfill assimilation. Microbial evaluation was done on virgin soil and later on soils used as covering material. This soil was later treated differently to see different effects that has on methane emission. Treatments applied were addition of compost in soil, moistured soil with methanotroph culture instead of water. Although methane was produced from the landfill, it was not as documented between 45 and 50%. We got between 6 and 18% production. In all the soils tested the uncultivated soil had the minimal emission as it emitted 0% methane. Sand, however, had some oxidation effect. The problem was that it is porous therefore gas migration is not restricted. This shows that the oxidative bacteria are available naturally is soils, but gets abandoned as the conditions favours their growth. The treatments done to soils had little effect as methane oxidation was not influenced or altered. This can be liked into in details. There have been some good observations in the assimilated landfill. As the landfill was not controlled the pH dropped and this in return produced more hydrogen as compared to methane. With all the altered gas balance produced the leachate changed.

This work takes a closer look at ceria catalyst synthesis through micelle self-assembly. We compare surfactants, precursors, solvent systems, and doping. The surfactants are the building blocks upon which the ceria can crystallize. The samples are calcinated to test their thermal stability. Characterization is performed using pXRD as well as physisorption. The samples that exhibited a higher thermal stability were characterized to have a high surface area as well as low fluctuations in crystallite size, pore volume, and pore size. Ceria synthesized with cerium (III) nitrate hexahydrate and CTAB in a water:ethanol mixture using sodium hydroxide showed to be the most effective at providing a thermally stable product. Doping the catalyst with titanium increased the thermal stability significantly. Select samples were run in a variety of fuel to oxygen ratios to determine the best conditions in which we could perform partial methane oxidation to recuperate hydrogen gas. Most of the experiments show oxygen depletion with minor changes in other gas levels indicating that there is no oxidation occurring. Curiously the oxygen levels do decrease. There is a possibility that there is a reaction occurring initially at room temperature and being exacerbated with further temperature increase.

This work takes a closer look at ceria catalyst synthesis through micelle self-assembly. We compare surfactants, precursors, solvent systems, and doping. The surfactants are the building blocks upon which the ceria can crystallize. The samples are calcinated to test their thermal stability. Characterization is performed using pXRD as well as physisorption. The samples that exhibited a higher thermal stability were characterized to have a high surface area as well as low fluctuations in crystallite size, pore volume, and pore size. Ceria synthesized with cerium (III) nitrate hexahydrate and CTAB in a water:ethanol mixture using sodium hydroxide showed to be the most effective at providing a thermally stable product. Doping the catalyst with titanium increased the thermal stability significantly. Select samples were run in a variety of fuel to oxygen ratios to determine the best conditions in which we could perform partial methane oxidation to recuperate hydrogen gas. Most of the experiments show oxygen depletion with minor changes in other gas levels indicating that there is no oxidation occurring. Curiously the oxygen levels do decrease. There is a possibility that there is a reaction occurring initially at room temperature and being exacerbated with further temperature increase.

Thesis (Ph.D.)--Washington State University. / Includes bibliographical references.

This work takes a closer look at ceria catalyst synthesis through micelle self-assembly. We compare surfactants, precursors, solvent systems, and doping. The surfactants are the building blocks upon which the ceria can crystallize. The samples are calcinated to test their thermal stability. Characterization is performed using pXRD as well as physisorption. The samples that exhibited a higher thermal stability were characterized to have a high surface area as well as low fluctuations in crystallite size, pore volume, and pore size. Ceria synthesized with cerium (III) nitrate hexahydrate and CTAB in a water:ethanol mixture using sodium hydroxide showed to be the most effective at providing a thermally stable product. Doping the catalyst with titanium increased the thermal stability significantly. Select samples were run in a variety of fuel to oxygen ratios to determine the best conditions in which we could perform partial methane oxidation to recuperate hydrogen gas. Most of the experiments show oxygen depletion with minor changes in other gas levels indicating that there is no oxidation occurring. Curiously the oxygen levels do decrease. There is a possibility that there is a reaction occurring initially at room temperature and being exacerbated with further temperature increase.

No description available.

This thesis described the development of new catalytic system for the conversion of natural gas (methane) to liquid products such as methanol and formaldehyde. This technology can allow the exploitation of small and medium size gas fields without the need to build an expensive gas to liquid plants or long pipelines. The technology is based on a concept of non-separating membrane reactor where an inorganic membrane paper serves as a catalyst support through which a reaction mixture is flowing under mild conditions and short residence times.

This thesis described the development of new catalytic system for the conversion of natural gas (methane) to liquid products such as methanol and formaldehyde. This technology can allow the exploitation of small and medium size gas fields without the need to build an expensive gas to liquid plants or long pipelines. The technology is based on a concept of non-separating membrane reactor where an inorganic membrane paper serves as a catalyst support through which a reaction mixture is flowing under mild conditions and short residence times.

Microbial oxidation of methane has attracted interest as an alternative process for treating landfill gas emissions. Approaches have included enhanced landfill cover layers and biocovers, passive gas drainage and biofiltration, and active gas extraction and biofiltration. Previous research has shown that microbial methane oxidation is affected by a number of factors, many of which are dependent on the environment in which the process is occurring. The aim of this research was to evaluate the behaviour and performance of a passive landfill gas drainage and biofiltration system operating in a temperate climate, and to identify and quantify the factors that determine the behaviour and performance of the system under such conditions. To achieve this a series of field trials were undertaken in Sydney, Australia, over a period of 4 years. The trials were designed to evaluate the effect of a range of factors, including landfill gas loading rate, temperature and moisture content of the biofilter media, biofilter media characteristics, and climatic conditions. The results of the field trials showed that a passive gas drainage and biofiltration system operating in a temperate climate can achieve methane oxidation efficiencies > 90% and that the behaviour and performance of a passive gas drainage and biofiltration system is primarily dependent on 3 factors: the landfill gas loading rate, which varies; the temperature of the biofilter media, which is affected by the temperature of the landfill gas being treated, the level of microbial activity occurring in the biofilter, and local climatic conditions; and the moisture conditions within of the biofilter media, which is affected by local climatic conditions and the characteristics of the biofilter media. Relationships between these factors and the performance of a passive biofilter operating in a temperate climate were developed, where able. A number of design concepts for passive landfill gas drainage and biofiltration were developed. A process for assessing the feasibility of applying the concepts and designing a passive landfill gas drainage and biofiltration system was also developed. In addition, guidelines and recommendations for the design of a passive landfill gas drainage and biofiltration system operating in temperate climate were developed.

Title from PDF of title page. / Document formatted into pages; contains 70 pages. / Thesis (M.Ch.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: SiC is a hard man-made material and has emerged as an excellent material for a wide range of applications which are exposed to extreme conditions such as high temperatures and harsh chemical environments. These applications range from SiC being used as an abrasive, to a refractory material, to a semiconductor material for high power and high frequency electronic devices. The properties of the material for each application is different, with the semiconductor grade material for electronic devices being the most refined. SiC, with its excellent thermal properties and high resistance to harsh chemical environments, lends itself to being an ideal support for catalyst systems. / ABSTRACT: Various characterisation & analysis techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography (GC) are used in this thesis to investigate the suitability of single crystal SiC for high temperature catalytic systems. Low temperature oxidation of methane was used to investigate the catalytic activity of: - Porous and standard 4H-SiC with and without Pd - Porous and Standard 6H-SiC with and without Pd. - Nanocrystalline Beta-SiC powder with and without Pd. Part of the samples were impregnated with Pd using Palladium Nitrate (Pd (NO3)2) which is a common precursor for Pd. Activation treatments which were investigated were oxidation and reduction. Oxidation was generally better in activating the catalyst, as was expected, since the PdO phase is known to be more active in oxidising methane. / ABSTRACT: A mixed set of Pd and PdO were observed by SEM and EDS which were the main characterisation techniques used to analyze the structure of the catalysts before and after the reaction. The Beta-SiC showed by far the best activity which could be attributed to the micro-crystalline powder format in which it was used, where as all other catalysts studied here were derived from crushed wafer pieces. Type II porous 4H-SiC was another of the samples which registered impressive results, vis-à-vis catalytic activity. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.