Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"MTBE"”.
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Aerobic Biodegradation of MTBE in Uncontaminated and Gasoline-Contaminated Aquifer Sediments
In this study, the biodegradation potential of MTBE in uncontaminated and previously contaminated aquifer sediments under aerobic conditions was investigated. Laboratory microcosms were constructed using aquifer samples collected from three different areas of a shallow gasoline-contaminated aquifer …
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Hydrothermal chemistry of methylene chloride and MTBE : experimental kinetics and reaction pathways
… methylene chloride and methyl tert-butyl ether (MTBE) hydrolysis in sub- and supercritical water have been measured experimentally at 250 bar over a range of temperatures from 100 to 600°C. The rate constants for both compounds showed a local maximum below the critical temperature of water …
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Removal of selected water disinfection byproducts, and MTBE in batch and continuous flow systems using alternative sorbents.
… (BDCM), methyl tertiary butyl ether (MTBE), bromate and bromide ions. Sorbents used included light weight aggregate (LWA), an inorganic porous material with unique surface characteristics, Amberlite® XAD-16, a weakly basic anion exchange resin, Amberjet®, a strongly basic anion …
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Characteristics and Mechanisms of Heavy Metal and MTBE Adsorption on Zeolites and Applications in Permeable Reactive Barriers
… a typical hydrophobic zeolite, is effective for MTBE adsorption due to its high adsorption capacity (53.55 mg/g in batch adsorption tests) and good regeneration characteristics. The adsorption reaches equilibrium within 24 hours and follows the Langmuir isotherm model and the Hill 5 kinetic …
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LITHOLOGIC AND HYDROGEOLOGIC CONTROLS ON THE OCCURRENCE, TRANSPORT, AND FATE OF MTBE IN FINE GRAINED GLACIAL-LACUSTRINE SEDIMENTS
… with dissolved phase contamination (including MTBE) extending 460 m west to Spring Creek. Though geochemical sampling has established the general plume extent, the influence of aquifer heterogeneities on plume position and transport behavior is poorly described. The purpose of this work is to …
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LITHOLOGIC AND HYDROGEOLOGIC CONTROLS ON THE OCCURRENCE, TRANSPORT, AND FATE OF MTBE IN FINE GRAINED GLACIAL-LACUSTRINE SEDIMENTS
… with dissolved phase contamination (including MTBE) extending 460 m west to Spring Creek. Though geochemical sampling has established the general plume extent, the influence of aquifer heterogeneities on plume position and transport behavior is poorly described. The purpose of this work is to …
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Biodegradation of Fuel Oxygenates in Northeastern United States Aquifers with an Analysis of Underground Storage Tank Leaks
… 20 years has been methyl tertiary butyl ether (MTBE), which has traditionally been viewed in both the scientific and the regulatory communities as relatively recalcitrant to biodegradation. However, cases of both in and ex situ MTBE biodegradation have recently been documented. In order to …
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Assessing the Spatial and Temporal Distribution of MTBE and BTEX Compounds in Lake Lewisville, Texas February 1999 - February 2000
… distribution of Methyl Tertiary-Butyl Ether (MTBE) and BTEX (Benzene, Toluene, Ethylbenzene, Xylenes) compounds were assessed in a multipurpose reservoir, Lake Lewisville, Texas between February 1999 and February 2000. Concentrations of MTBE ranged from 0.0 - 16.7 mg/L. Levels of MTBE in the …
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Degradation of gasoline oxygenates in the subsurface
… alcohol (TBA), methyl tertiary butyl ether (MTBE) and ethyl tertiary butyl ether (ETBE) are compounds with the potential for use as oxygenates in reformulated gasolines. Being relatively soluble in water, these organics, if accidentally discharged into the subsurface, may rapidly spread and …
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Anaerobic biodegradation of selected organic compounds with and without inhibition of sulfate reducing bacteria
… of methanol, methyl tert-butyl ether (MTBE), toluene, phenol, and 2,4- dichlorophenol. In addition, biodegradation rates of these compounds at various initial concentrations with and without inhibition of sulfate reducing bacteria were determined along with anaerobic biodegradation rate …
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Fuel component effects on hydrocarbon emissions from a spark-ignition engine
… with the following four major fuel components: MTBE, toluene, m,p-xylene, and iso-octane. For each of these components, new fuel mixtures were blended by increasing the percent volume of that particular component by three different increments. A spark-ignition engine was run at steady-state …
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Alcohols and other oxygenates in automotive fuels
… oxygenate showed some variation with methanol/MTBE/3 methylbutan-2-one and methanol/MTBE/4 methyl pentan-2-one knocking less than expected and methanol/MTBE/TBA also showing good knock resistance. Further tests to optimise initial findings suggested a blend of methanol and MTBE to be superior …
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Experiment, thermodynamic properties and modeling on combustion of methyl tert-butyl ether : isobutane and isobutene and thermodynamic properties of chloro alkanes and alkenes
The reaction systems: methyl tert-butyl ether (MTBE) unimolecular decomposition, MTBE radicals + O_2, tert-butyl radical +O_2, isobutene + HOO. (HO_2),isobutene + OH, sobutene-OH adducts + O_2, and allylic isobutenyl radical + O_2, are important systems in the understanding the oxidation chemistry …
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In-situ photocatalytic remediation of organic contaminants in groundwater
… target contaminant is methyl tert butyl ether (MTBE), a popular gasoline additive in the past three decades, which gives the water an unpleasant taste and odour at 20 µg L-1, making it undrinkable. This research consists of three major parts, i.e. (i) establishing a suitable catalyst …
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The effects of Fe(III) reduction on biodegradation of fuel oxygenates and chlorinated ethenes
Fuel oxygenates, methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA), and chlorinated ethenes (TCE, cis-DCE and VC) are two groups of contaminants prevalent in groundwater systems. Fe(III) reducing conditions are dominant in many sedimentary environments. However, the effects of Fe(III) …
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Anticipation nationwide risks to drinking water : predicting local scale contamination of community supply wells by gasoline additives
… increased addition of methyl-tert-butyl-ether (MTBE) to U.S. gasolines, nationwide MTBE contamination of thousands of drinking water supply wells has been widely documented, reflecting enormous environmental and economic costs. Due to its abundance in gasoline, high aqueous solubility, and slow …
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Development of zeolite based acid catalysts for the synthesis of methyl tertiary butyl ether
Methyl tertiary butyl ether (MTBE) an antiknock additive presently used in gasoline blends as a safer alternative to lead compounds, is currently synthesized industrially from methanol and isobutene over an acidic ion-exchange resin Amberlyst-15. This commercial catalyst, although very active, …
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Extraction of alcohols from gasoline using solid phase microextraction (SPME)
… are ethanol (EtOH) and methyl tert-butyl ether (MTBE). However, MTBE is now forbidden by the environmental protection agency (EPA) because of the possibility of ground water contamination. The current trend is to use EtOH, therefore this work focuses on the analysis and quantification of EtOH in …
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Computational Tools for Improved Analysis and Assessment of Groundwater Remediation Sites
… aquifers (specifically tracking benzene and MTBE) through statistical techniques. With the knowledge of source area residual saturation, groundwater velocity, and contaminant plume source length, the time to remediate a site contaminated with either benzene or MTBE can be determined across a …
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Optimización del diseño y rediseño de procesos químicos complejos bajo incertidumbre mediante cooperación de técnicas de programación matemática y metaheurísticas
… propuesta al proceso de producción de MTBE proporciona resultados fiables. Estos resultados experimentales, demuestran las ventajas obtenidas al paralelizar el proceso de diseño utilizando como plataforma una red de ordenadores, logrando con esto resolver problemas de dimensiones …
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