Physical Sciences and Mathematics Commons^™

Infiltration-Controlled Combustion Of Lithium And Magnesium Powders And Reactions Of Lithium With Oxygen And Carbon Dioxide, Kevin Samuel Estala Rodriguez

Open Access Theses & Dissertations

Chemical heat integrated power systems are of great interest for space missions where solar energy, nuclear energy, and batteries are not available or are not practical to use. A new concept of a power system is a metal combustor coupled with a chemical oxygen generator, where the generated oxygen infiltrates through the metal powder or combustion products. The combustion of lithium and magnesium powders under these conditions has not been studied yet. The present work investigates combustion of magnesium powder and stabilized lithium metal powder (SLMP) ignited by a laser inside a closed chamber filled with O2 or CO2. It …

Ferrate(Vi) For Wastewater Treatment : Phosphorus Removal, Lei Zheng

Theses, Dissertations and Culminating Projects

Phosphorus (P) is a major nutrient present in municipal wastewater. Without proper treatment and management, residual P in treated wastewater finally enters into natural receiving water bodies. Nutrient pollution resulting from excessive P, together with the other nutrient, i.e. nitrogen (N), is a leading cause of eutrophication, a ubiquitous U.S. water quality issue. An overgrowth of algae during eutrophication brings extremely adverse impacts on the water quality. The algal bloom can rapidly deplete dissolved oxygen, lead to the death of aquatic life, increase water turbidity, and cause taste and odor issues. Moreover, some harmful algal boom can produce toxins to …

Preservation Protocols For Maintaining Species Stability Of Arsenic, Chromium, And Selenium In Water Samples, Contessa Lowery

Water Resources Professional Project Reports

Water quality has become an increasing concern in recent years. The environmental challenges surrounding water quality include the presence of dissolved metals and their potential impact on human health and the environment. The challenge is exacerbated because many important metals have multiple oxidation states, which affect the health and environmental behavior of the metal. Many metals are known carcinogens and increased anthropogenic effects have inexorably made metals’ accumulation an imposing threat. Analytical instrumentation has advanced in many areas, making it now possible to measure very low concentrations of multiple elements in water. Current interest is determining the chemical speciation of …

An Overview Of Dynamic Heterogeneous Oxidations In The Troposphere, Elizabeth A. Pillar-Little, Marcelo I. Guzman

Chemistry Faculty Publications

Due to the adverse effect of atmospheric aerosols on public health and their ability to affect climate, extensive research has been undertaken in recent decades to understand their sources and sinks, as well as to study their physical and chemical properties. Atmospheric aerosols are important players in the Earth’s radiative budget, affecting incoming and outgoing solar radiation through absorption and scattering by direct and indirect means. While the cooling properties of pure inorganic aerosols are relatively well understood, the impact of organic aerosols on the radiative budget is unclear. Additionally, organic aerosols are transformed through chemical reactions during atmospheric transport. …

Catalytic Oxidation And Depolymerization Of Lignin In Aqueous Ionic Liquid, Lalitendu Das, Siquan Xu, Jian Shi

Biosystems and Agricultural Engineering Faculty Publications

Lignin is an integral part of the plant cell wall, which provides rigidity to plants, also contributes to the recalcitrance of the lignocellulosic biomass to biochemical and biological deconstruction. Lignin is a promising renewable feedstock for aromatic chemicals; however, an efficient and economic lignin depolymerization method needs to be developed to enable the conversion. In this study, we investigated the depolymerization of alkaline lignin in aqueous 1-ethyl-3-methylimidazolium acetate [C₂C₁Im][OAc] under oxidizing conditions. Seven different transition metal catalysts were screened in presence of H₂O₂ as oxidizing agent in a batch reactor. CoCl₂ and …

Nitrate Radicals And Biogenic Volatile Organic Compounds: Oxidation, Mechanisms And Organic Aerosol, Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Hermann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert Mclaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, Rahul A. Zaveri

Chemistry Faculty Publications

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO₃) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO₃-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number …

The Decline And Recovery Of Thermal Oxidative Stability Of Ultra-Low Sulfur Diesel Blends, Abigail Schoor Cohen

Electronic Theses and Dissertations

Dissertation supervised by Professor Bruce D. Beaver

The oxidative stability of ultra-low sulfur diesel (ULSD) has generally been expected to continuously decline over time. However, recent studies have suggested that it may fluctuate.^1-2 In this study, the oxidative stability of stored commercially purchased ULSD was monitored with a methanol extraction method.³ In this methodology, proposed by Hardy and Wechter, fuel blends are extracted with methanol before and after thermal stressing.⁴ The methanol-soluble layer contains the oxygenated and oxidizable components of the fuel (SMORS) and the change in this mass upon stressing thus represents the oxidative stability of …

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …

Sustainable Decolorization Of Reactive And Acid Dye Wastewater Using Photo-Fenton Oxidation Both With And Without Biodegradation: Laboratory And Field Studies, Marissa R. Jablonski

Theses and Dissertations

Photo-Fenton oxidation is an advanced oxidation process (AOP) used to degrade low-concentration textile dye wastewater using expensive chemicals. The technique has shown promise in laboratory-scale projects, but has not been scaled up sustainably to function for industry. Aerobic biodegradation is a common biological treatment method used in large-scale textile industrial applications that generates large amounts of hazardous biological waste. This waste is often left open to the elements and subsequently leaches into natural waterways or onto land. This is the first study of its kind to combine the two to treat cottage-scale industry-grade textile wastewater with a dye concentration of …

Speciation Behavior Of Americium Higher Oxidation States For The Separation Of Americium From Curium, Catherine Lynn Riddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several countries are currently expanding the use of nuclear energy as a method for the safe generation of carbon free energy and a number are evaluating starting up a nuclear power program. Closed fuel cycle technologies may be key to waste reduction and a sustainable nuclear energy future and to support the development of more efficient fuel cycles, the investigation of the chemical properties of key actinides is at the forefront of separations research. In this work the characterization of higher oxidation states of americium (Am) has been performed using spectroscopic methods. Americium in the formal oxidation state of Am(V) …

2014 Martz Summer Conference Poster Session, University Of Colorado Boulder. Getches-Wilkinson Center For Natural Resources, Energy, And The Environment, University Of Colorado Boulder. Airwatergas Sustainability Research Network

Water and Air Quality Issues in Oil and Gas Development: The Evolving Framework of Regulation and Management (Martz Summer Conference, June 5-6)

1 page.

This Conference is presented by the Getches-Wilkinson Center for Natural Resources, Energy, and the Environment, in conjunction with the Air-Water-Gas Sustainability Research Network. Technological advances for extracting oil and gas from shale deposits have ushered in a new era of energy development in key resource-rich pockets throughout the US. In this event, we review the ongoing efforts of governments and industry to develop the regulatory and management practices necessary to protect water and air resources, drawing on the latest scientific research to tackle areas of uncertainty and to inform future action.

Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo

Open Access Theses & Dissertations

Silica and nanoparticles of Pt, Au, and Ag supported on silica were tested for the ability to oxidize dibenzothiophene (DBT) to sulfone. High performance liquid chromatography was used to study the removal of DBT from solution. In addition, X- ray diffraction, infrared spectroscopy and Raman Spectroscopy were used to characterize the product of the oxidation reaction. Further studies involved the use X-ray absorption spectroscopy to characterize the nanoparticle catalysts before and after the oxidation reaction.

To better understand the reaction, silica was synthesized at different pHs using three different acids. The acids used to synthesize the silica were HCl, HNO3, …

New Generation Of Catalytic Technologies For Environmental Protection On The Base Of Fiber-Glass Catalysts, Bair S. Balzhinimaev, Andrey N. Zagoruiko

Andrey N Zagoruiko

Novel glass-fiber based catalysts containing extra-low amounts of noble metals (0.01-0.02% mass of Pt or Pd) demonstrate unique performance in many catalytic reactions, resulted from the ability of the glass fibers to stabilize the transient metals in the glass bulk in a highly-dispersed form. Moreover, specific heat/mass transfer properties, original geometry, high flexibility and high mechanical strength of such catalysts give the way to develop really new catalytic processes and novel reactor designs. The paper is dedicated to the successful research and development (from fundamental research issues to pilot and semi-industrial tests) of different catalytic oxidation processes based on application …

Peroxynitrite Chemistry: Formation, Decomposition And Possible Deactivation Mechanisms By Thiols, Olufunke Modupe Olagunju

Dissertations and Theses

Kinetics of formation and decomposition of peroxynitrite was studied in acidic and buffer solutions. Peroxynitrous acid was formed in acidic media by the reaction of H₂O₂ with HNO^₂ and NO +. Bimolecular rate constant for reaction of H²O² with HNO^₂ at 25°C was determined to be 3.7 × 10 3 M-¹ s-¹. Peroxynitrous acid formed is highly unstable with half life of approximately 1 second. Decomposition of peroxynitrite is highly pH-dependent. In acidic media, peroxynitrous acid decomposes to nitrate while at neutral to slightly basic media, products of decomposition …

Physical And Oxidative Removal Of Organics During Fenton Treatment Of Mature Municipal Landfill Leachate, Yang Deng

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Municipal landfill leachate, especially mature leachate, may disrupt the performance of moderately-sized municipal activated sludge wastewater treatment plants, and likewise tend to be recalcitrant to biological pretreatment. Recently, Fenton methods have been investigated for chemical treatment or pre-treatment of mature leachate. In this paper, the results of laboratory tests to determine the roles of oxidation and coagulation in reducing the organic content of mature leachate during Fenton treatment are presented. The efficiencies of chemical oxygen demand (COD) oxidation and coagulation were tested, and the ratio of COD removal by oxidation to that by coagulation was assessed, under various operating conditions. …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics - Phase Three, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The proposed work will combine chemical kinetics and hydrodynamics in target and test-loop lead-bismuth eutectic (LBE) systems to model system corrosion effects. This approach will result in a predicative tool that can be validated with corrosion test data, used to systematically design tests and interpret the results, and provide guidance for optimization in LBE system designs. The task includes two subtasks. The first subtask is to try to develop the necessary predictive tools to be able to predict the levels of oxygen and corrosion products close to the boundary layer through the use of Computational Fluid Dynamics (CFD) modeling. The …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Phase Two, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The proposed work will combine chemical kinetics and hydrodynamics in target and test-loop lead-bismuth eutectic (LBE) systems to model system corrosion effects. This approach will result in a predicative tool that can be validated with corrosion test data, used to systematically design tests and interpret the results, and provide guidance for optimization in LBE system designs. The task includes two subtasks. The first subtask is to try to develop the necessary predictive tools to be able to predict the levels of oxygen and corrosion products close to the boundary layer through the use of Computational Fluid Dynamics (CFD) modeling. The …

Experiment, Thermodynamic Properties And Modeling On Combustion Of Methyl Tert-Butyl Ether : Isobutane And Isobutene And Thermodynamic Properties Of Chloro Alkanes And Alkenes, Chiung-Ju Chen

Dissertations

The reaction systems: methyl tert-butyl ether (MTBE) unimolecular decomposition, MTBE radicals + O₂, tert-butyl radical +O₂, isobutene + HOO. (HO₂),isobutene + OH, sobutene-OH adducts + O₂, and allylic isobutenyl radical + O₂, are important systems in the understanding the oxidation chemistry of MTBE, tertiary butyl radical (C3C.), and sobutene, are analyzed. Thermochemical parameters are determined by ah initio Møller-Plesset (MP2(full)/6-31g(d)), complete basis set model chemistry (CBS-4 and CBS-q with MP2(full)/6-31g(d) and B3LYP/6-31g(d) optimized geometries), density functional (B3LYP/631g(d)), semi-empirical MOPAC (PM3) molecular orbital calculations, and by group additivity estimation. Thermochemical …

Oxidation Of Isobutane And Isobutene Reaction Pathways And Detailed Mechanism, Chiung-Ju Chen

Theses

A reaction mechanism consisting of 248 elementary reactions and 138 species has been developed to model experimental systems - decomposition of 2,2,3,3 tetramethylbutane in the presence of oxygen and oxidation of isobutene. This elementary reaction mechanism based on two important reaction systems: tert-butyl radical with O₂ and allylic isobutenyl radical with O₂, plus their subsystems, such as isobutene + HO₂, isobutene + OH and allylic isobuteny1hydroxy + O₂. Thermochernical kinetic parameters are developed for each elementary reaction and a chemical activation kinetic analysis using quantum RiceRamsperger-Kassel (QRRK) theory for k(E) and modified strong …

I: Reaction Of Ch3c1 With H2 And Ch4 Under Oxidation And Pyrolysis Conditions Ii: Kinetic Analysis Of C2h6, C2h4, And C2h2 Reactions With Oh, O, H, And Cl, Qing-Rui Yu

Theses

Experimental and detailed modeling are presented for the high temperature combustion systems involving CH₃Cl/CH₄/O₂ and C₃3Cl/H₂/O₂ reactions. More important C2 species reaction rate constant are created. A mechanism incorporating 263 step elementary reactions and 76 stable compounds and active radicals is developed based on (1) fundamental thermochemical and Kinetic principles (2) Quantum Rice-Ramsperger-Kassel (QRRK) theory analysis (3) accurate thermodynamic Properties and thermochemical analysis (4) reliable experimental data to validate our model.

The study of Part II evaluates and analyzes theoretically the rate constants of C₂H₆, C …

A Membrane-Organic Phase Oxidation Process For The Destruction Of Toxic Organics In Hazardous Wastewaters, Charles E. Hamrin Jr., Dibakar Bhattacharyya, William K. Glynn

KWRRI Research Reports

The examination of the extraction/oxidation of organic solutes in a two phase oxidation process was undertaken to discern the important parameters and the process mechanism of this system. Several parameter were adjusted to measure their effect on the disappearance rate of each organic from the water phase. The water to PFD volume ratio proved to be the most sensitive parameter affecting the disappearance rate, although temperature was also significant. Comparison with one phase oxidation systems demonstrated that the water/PFD system improved on the reduction of organics from the water phase. B-napthol oxidation increased over 50% in a 2/6 water/PFD volume …

Surface Area Of Coal As Influenced By Low Temperature Oxidation Processes, Salvador Leon Arredondo

Dissertations and Theses

The possibility of increasing the amount of readily accessible surface area by enlarging the 5 A pore was examined via pretreating the PSOC-371 coal with gases such as nitrogen, nitrogen-oxygen, and ozone-oxygen and hydrogen peroxide solutions. Surface areas were obtained from nitrogen adsorption at 77 K and carbon dioxide adsorption at either 298 or 195 K for each sample before and after treatment.