Chemical Engineering Commons^™

Solvent Engineering Of Molybdenum Disulfide Electrocatalyst For Hydrogen Evolution., Robert Carl Spalding

Electronic Theses and Dissertations

Energy is at an exponentially growing demand, and to keep up with these demands new technologies for renewable energy have received increased attention. Hydrogen plays a vital role in water electrolysis and fuel cells, as the hydrogen evolution reaction (HER) is the main step water splitting process. Most of the current electrocatalysts for HER are dominated by platinum and other precious metals due to their low over-potential and small Tafel slope, however, they are extremely costly. For this reason, cost-effective non-precious metal catalysts must be developed. Transition metal dichalcogenides, such as molybdenum disulfide (MoS2), are abundant and have recently shown …

Mixed Metal Oxide Nanowires Via Solid State Alloying., Veerendra Atla

Electronic Theses and Dissertations

Mixed metal oxide materials with composition control find applications in energy conversion and storage processes such as heterogenous catalysis, photoelectrochemical catalysis, electrocatalysis, thermal catalysis, and lithium-ion batteries. Mixed metal oxides and/or complex oxides with composition control and in one-dimensional form as nanowires could be interesting to various catalysis applications due to control on single crystal surfaces, active sites, acidity versus basicity site density, and oxygen vacancies. The major challenge is to synthesize mixed metal oxide nanowires beyond binary oxides with composition control. In this dissertation, solid state alloying of binary oxide nanowires with solid and liquid precursors is studied to …

Aggregation Dynamics Of Bulk Nanoparticle Haloing Systems And The Influence Of Non-Ambient Temperatures., Marzieh Moradi

Electronic Theses and Dissertations

One of the methods of assembling colloids into 3D crystal structures is through the use of nanoparticle haloing. Nanoparticle haloing is a stabilization mechanism in binary particle suspensions possessing both a size and charge asymmetry, with which the nanoparticles aid in the bulk suspension’s stability. By altering the volume fractions of nanoparticles, it is possible to control the effective repulsion between the microparticles. Understanding the colloidal interactions and aggregate crystallinity as a function of nanoparticle concentration, temperature, and time are key challenges in developing future materials and designing crystalized 3D colloidal systems. In this study, we investigated the effect of …

Exploring Meerwein-Ponndorf-Verley Reactions Using Metal Organic Framework Catalysts., Yuehan Zhou

Electronic Theses and Dissertations

The Meerwein–Ponndorf–Verley (MPV) reaction is a reaction that is used to reduce aldehydes and ketones to the corresponding alcohols with the added use of catalysts. The common metal triflate catalysts used in MPV reduction incur tremendous environmental hazards and high operational costs. The use of Metal-Organic Frameworks (MOFs) as catalysts can be an alternative due to MOFs’ extraordinarily high surface areas, ultrahigh porosities, tunable pore sizes, modifiable internal surfaces, and numerous framework structures. Moreover, using MOFs as catalysts for MPV hydrogenation is economically viable due to low operational and material costs. This study involves using MOF-808 (Hf) in the MPV …

Room Temperature Alkali Treatment Of Rice Straw For Enhanced Enzymatic Hydrolysis., Seth Mains

Electronic Theses and Dissertations

Due to the pollution of fossil fuels due to greenhouse emissions, researchers continue to search for alternative methods that allow for the clean production of energy, fuels, and polymer fibers. A method currently under investigation is the use of lignocellulosic biomass as a solution to current problems with energy and polymer fiber production. Through the process of pretreatment, possibilities for lignocellulosic biomass expand due to improved accessibility of the cellulose and hemicellulose which can be broken down via enzymatic hydrolysis into C5 and C6 sugars such as xylose and glucose. This study investigated the fermentation of the rice straw into …

Wetting And Drying Dynamics For Tio2 With Pbs Quantum Dots., Kelly M. Lee

Electronic Theses and Dissertations

Initial solar cells utilized silicon and alloys for their economic viability. Photoelectrochemical photovoltaic cells were discovered with technological advancement which increased solar efficiency and further improved economic feasibility leading to quantum dot sensitized solar cells. Lead sulfide quantum dots and titanium dioxide were studied for wetting and drying effects. Zeta potential, pH values, SEM, and optical microscopes quantified or observed the colloidal suspension and dried sample behavior. Combined mixtures of lead sulfide and titania were dried at 3.6 pH and 12.56 pH values. This due to the observed zeta potential isoelectric point of titania, and behavior showed increased stability occurring …

The Study Of Copper Corrosion Mechanisms Using Electrochemical Experimental Techniques., Evan Grimm

Electronic Theses and Dissertations

The purpose of this study was to discover and thoroughly explain the corrosion mechanisms of copper in saltwater, tap water and deionized water, and to apply these methods and findings when testing the corrosion mechanisms of other materials. The experimental procedure consisted of measuring the open circuit potential, electrochemical impedance spectroscopy, linear sweep voltammetry, and Tafel analysis.

The copper was found to corrode at a greater rate in saltwater, followed by tap water then deionized water, with a larger difference between saltwater and tap water than between tap water and deionized water. Each reaction was found to be both kinetically …

Modified Electrode Surfaces With Hydrogen Evolution Reaction Catalysts Derived From Electropolymerized Complexes With Redox Active Ligands., Amanda Mae Arts

Electronic Theses and Dissertations

The demand for energy is growing exponentially, and to keep up with these demands new technologies for renewable energy have received increased attention. Hydrogen is one of the most promising energy sources for the future and plays a vital role in water electrolysis and fuel cells, as the hydrogen evolution reaction (HER) is the main step in the water splitting process. To increase the reaction rate and improve efficiency for the water electrolysis, catalysts are used to minimize the overpotential.

Most of the current electrocatalysts for HER are heterogeneous in nature and are dominated by platinum and other precious metals …

Mapping Three Dimensional Interactions Between Biomolecules And Electric Fields., Joseph Patrick Brian P.E.

Electronic Theses and Dissertations

Electroporation is a technique that induces the formation of open pores in cell membranes by the application of an electric field. Electroporation is widely practiced in research and clinical work for transfection of genetic sequences and drug molecule transport through the membrane barrier. However, a full theoretical explanation of the molecular mechanisms and thermodynamics responsible for pore formation, structure, and longevity does not yet exist. Advances in molecular dynamics simulations have enabled theoretical studies of electroporation with previously unobtainable fidelity spanning biologically relevant timescales. All-atom simulations utilizing the recently developed method of computational electrophysiology demonstrate that pore size correlates to …

Predicting Henry's Law Constants Of Volatile Organic Compounds Present In Bourbon Using Molecular Simulations., Christopher A Abney

Electronic Theses and Dissertations

Henry’s Law describes the partitioning of molecules into liquid and gas phases at low concentrations. Henry’s Law, which is based upon a species-dependent constant and the gas phase partial pressure, is useful for predicting phase behavior of dilute solutes. However, Henry’s Law constants are difficult to measure experimentally or to predict using structure-property or thermodynamic models. Herein, molecular simulations were used to calculate Henry’s Law constants for 18 volatile organic compounds (VOCs) present in bourbon. The novel simulations analyzed solvation thermodynamics of small organic molecules in 120 proof ethanol. A fast-growth non-equilibrium free energy method was used in which the …

Annealing Of Encapsulated Heavy Metals From Brine Water Utilizing Microwave Enabled Sol-Gel Process, Adam Michael Flynn

Electronic Theses and Dissertations

Various waste encapsulation strategies have been investigated to solidify and stabilize heavy metal wastewater for proper long-term storage. This work aims to enhance a method of novel sol-gel encapsulation of heavy metals from mock brine waters using tetramethyl orthosilicate with the addition of an annealing step at various temperatures in order to reduce leaching of metals from the silica monoliths when exposed to water. The metals tested for encapsulation and leaching were mercury (II) chloride, potassium dichromate, sodium selenite, boric acid, cadmium chloride, and copper (II) acetate. The annealing of the silica monoliths led to an increased degree of for …

Image Analysis Of Charged Bimodal Colloidal Systems In Microgravity., Adam J. Cecil

Electronic Theses and Dissertations

Colloids are suspensions of two or more phases and have been topics of research for advanced, tunable materials for decades. Stabilization of colloids is typically attributed to thermodynamic mechanisms; however, recent studies have identified transport or entropic mechanisms that can potentially stabilize a thermodynamically unstable colloidal system. In this study, suspensions of silsesquioxane microparticles and zirconia nanoparticles were dispersed in a nitric acid solution and allowed to aggregate for 8-12 days in microgravity aboard the International Space Station. The suspensions were subsequently imaged periodically at 2.5x magnification. Due to the inadequacy of existing image analysis programs, the python package “Colloidspy” …

Image Analysis Of Colloidal Systems For Pair And Triplet Correlations., Brianna Price

Electronic Theses and Dissertations

Interactions among colloidal particles drive stability of suspensions or the assembly of particles into larger superstructures such as agglomerates or crystals. Typically, colloidal interactions are modeled using pairwise interaction potential energies which consider the interactions between pairs of particles. However, additional particles can modulate pair potentials, leading models to predict incorrect behavior. To analyze the effects of three-body interactions on the structuring of colloidal systems, pair and triplet correlation functions are calculated from published experimental data. These correlation functions are then translated into empirical pair and triplet potentials of mean force, which are then used to model systems more accurately …

The Use Of Nanoparticles And Electrospun Fibers For Intravaginal Delivery To Treat Viral And Bacterial Infections And Electrophysiological Measurements Of Synthetic Chloride Channels., Farnaz Minooei

Electronic Theses and Dissertations

Female reproductive viral and bacterial infections affect millions of women worldwide. Given the diversity and magnitude of these unmet reproductive health challenges, topical administration of antiretrovirals (ARVs) and antibiotics have emerged as promising approaches to maintain and restore reproductive health. However, currently available intravaginal dosage forms often suffer from low user adherence and the need for frequent, daily administration to achieve therapeutic effect. To address these challenges, the broad goal of this research was to focus on the development of new localized nanoparticle (NP) and electrospun fiber dosage forms to prolong the delivery and enhance the efficacy of active agents …

Aqueous Redox Flow Batteries With Boron Doped Diamond As An Electrode., Alex M. Bates

Electronic Theses and Dissertations

As the interest and implementation of renewable energy accelerates, so does that of grid energy storage. It is widely believed that a cost-effective energy storage technology will bring about the proliferation of renewable energy. Redox flow battery (RFB) technology represents a promising solution to cost-effective grid energy storage. Compared to other technologies, RFBs have a long lifetime, high efficiency, are non-flammable, significantly reduce cost, and separately scale power and energy. The separation of power and energy enables increased energy capacity by simply adding electrolyte volume. Of the challenges facing RFB technology, one readily apparent is the cost of the active …

Addition Of Fermentation Experiment To Unit Operations Laboratory, Jeremy T. Rone

Electronic Theses and Dissertations

With the growth of the distillery and brewery industries and the potential jobs created for chemical engineers, it is imperative to equip the chemical engineering graduates from the University of Louisville with knowledge of bioreaction kinetics and experience in performing calculations to solve for concentration profiles and reaction rates. To accomplish this, it is recommended to add a fermentation experiment to the Unit Operations Laboratory II course.

Four groups of students from the Spring 2020 Unit Operations Laboratory II course performed the fermentation experiment. They were able to successfully complete all lab requirements as well as analyze the results and …

Labview Improvements And Equipment Redesign Of Unit Operations Distillation Column, Madalyn S Wead

Electronic Theses and Dissertations

Unit Operations labs are important tools to provide hands-on learning with various chemical processes. The distillation lab experiment allows students to connect equations and definitions from textbooks to the physical processes of distillation as they occur. LabVIEW was the software development tool used to create a program to control the distillation column from startup to shutdown. Improvements were made to both the distillation process equipment and the LabVIEW code to create a more interactive lab experience, enhance students’ conceptual understanding of distillation, and prepare students for their future career as chemical engineers.

Equipment addressed included non-linear valves, malfunctioning temperature and …

Determination Of Selenite And Selenate In Wet Flue Gas Desulfurization Process Water Through Ic-Icp-Ms And Hg-Icp-Aes, Samuel Anthony Kelty

Electronic Theses and Dissertations

During coal-fired electric power production, coal bound elemental selenium is released into the gas phase and oxidized to selenite and selenate in the wet flue gas desulfurization (WFGD) unit. Selenite and selenate solubilize in the WFGD process water. A process water system at a coal fired power plant contributes to environmental regulation compliance by removing the selenium species from WFGD process water. A selenium speciation method was developed for the purpose of better monitoring the selenium species present in the “treated” process water and to aid the process water system in meeting compliance with the Environmental Protection Agency’s Effluent Limitation …

Non-Invasive Detection And Assessment Of Coronary Stenosis From Blood Mean Residence Times., Javad Hashemi

Electronic Theses and Dissertations

Coronary artery stenosis is an abnormal narrowing of a coronary artery caused by an atherosclerotic lesion that reduces lumen space. Fractional flow reserve (FFR) is the gold standard method to determine the severity of coronary stenosis based on the determination of rest and hyperemic pressure fields, but requires an invasive medical procedure. Normal FFR is 1.0 and FFR RT, to account for varying volume and flow rate of individual segments. Blood_RT was computed in 100 patients who had undergone the pressure-wire FFR procedure, and a threshold for Blood_RT was determined to assess the physiological significance of a stenosis, …

Stabilization Of Bimodal Colloidal Systems Via Nanoparticle Haloing In Microgravity., Luke Hawtrey

Electronic Theses and Dissertations

Colloidal suspensions typically contain a multi-phase system of solid particles suspended in a liquid medium. Colloids are widely used in industrial applications such as inks, paints, motor oils, foods, cosmetics, and many more. Colloidal systems are typically formed by the interaction of the attractive van der Waals forces and one or more repulsive forces. These repulsive forces include electrostatic repulsion, steric hindrance, and nanoparticle haloing. Nanoparticle Haloing (NPH) is a phenomenon discovered in 2001 as a viable method to stabilize colloidal systems of uncharged silica microparticles using highly charged zirconia nanoparticles. For this thesis the effects of NPH were tested …

A Kinetic And Thermodynamic Model Of Ethylene Dichloride Pyrolysis., Travis J Czechorski

Electronic Theses and Dissertations

Ethylene dichloride (EDC) is a precursor for the production of vinyl chloride (VCM) which is subsequently polymerized to form polyvinyl chloride (PVC). To convert EDC to VCM, EDC undergoes a pyrolysis process in the absence of oxygen at temperatures exceeding 500C. However, process yields are limited by the uncontrolled production of side-products that can degrade the quality of PVC and poison the reactor. Thus, tight process controls and costly separations guided by heuristics and plant operator experience are used to optimize EDC pyrolysis. To improve the process, I have programed a kinetic model of EDC pyrolysis based upon estimations of …

Purification Of Biomass Hydrolyzates For The Promotion Of Xylose Diester Formation, Laura Fernandez

Electronic Theses and Dissertations

The application of a novel xylose isolation procedure using phenyl boronic acid esterification has been limited to the hydrolyzates of low extractive biomasses like hardwoods and agricultural resides. Hydrolyzates with lower sugar and higher extractive concentrations, like softwoods, have not yielded xylose, or even xylose diester (XDE), the first intermediate product in the new process, under the same conditions. This research applied evaporation concentration, adsorbent separation and membrane filtration to these lower performing biomass hydrolyzates to maximize the yield of the XDE formation step of the new xylose extraction process. Lab-scale tests of these techniques were applied to pine hydrolyzate …

Fluid Flow Analysis Of Diluted Evaporating American Whiskey Droplets., Martin J. Brown Vi

Electronic Theses and Dissertations

The recent discovery of the unique structures, whiskey webs, formed when the evaporation of diluted American whiskey, has raised many questions as to the nature of the structures. Their formation process follows as such: (1) dilution of the whiskey to form nanoaggregates, (2) formation of a monolayer at the air-liquid interface, (3) chaotic ethanol evaporation caused monolayer collapse (via dynamic pressure), (4) bulk fluid evaporation caused monolayer collapse (via reduction of surface area), where the web-like structures reside on the surface, and finally, (5) web-like structures deposit on the substrate. The webs imaged via SEM had a striking resemblance to …

Synthesis, Characterization, And Evaluation Of Metal Complexes With Cancer Selective Anti-Proliferative Effects And Hydrogen Evolution Catalytic Properties., Nicholas Vishnosky

Electronic Theses and Dissertations

Bis-thiosemicarbazones (BTSC) and their metal chelates have properties that are useful in several different scientific fields. These systems have already received attention in major fields of biology and engineering. Hydrogen evolution reaction (HER) catalysts need to be cheap and operate under minimal overpotentials with a long lifetime. The treatment of cancer requires, novel agents that have potent cytotoxic activity against cancer cells while displaying minimal side effects. In this dissertation the modular synthesis of these bis-thiosemicarbazone systems is utilized to regulate the redox chemistry for employment in the desired sector of chemistry. The ligand and metal chelates synthesized were characterized …

Capture And Release Gels For Optimized Storage (Cargos), Theodore S. Kalbfleisch Ii

Electronic Theses and Dissertations

Unassisted, the lifetime of many proteins outside their natural environment is very short. Scientists generally need to extract the sample, often in remote locations, and then transport, isolate, and store such biospecimens relatively far from the point of origin in order to study them. Currently, the most commonly used methods for storage of biospecimens are cryopreservation or refrigeration which, though effective, have their fair share of flaws. Cryopreservation and refrigeration-based storage of biospecimens requires a great deal of space and other resources to be effective. Furthermore, the hardware required for cold storage does not transport well. These factors make such …

Nanowire Based Adsorbents/Catalysts For Co2 Capture And Utilization., Apolo Nambo

Electronic Theses and Dissertations

Even today, the major energy source is fossil fuels, which release CO₂, a greenhouse gas that contributes to global warming. CO₂ capture, storage (CCS) and/or utilization (CCU) technologies are two routes to mitigate this problem. Sorbents are being investigated in either temperature swing or pressure swing absorption approaches for carbon capture from flue gases. Solid sorbent based technology is a promising one but suffers from slow kinetics, low capacity and need for high temperatures. Thus, new sorbent materials that can have good CO₂ sorption capacity, recyclability are sought. Similarly, one of the utilization approaches for CO …

Plasma-Assisted Liquid Phase Epitaxy Of Gallium Nitride Using Molten Gallium., Daniel Felipe Jaramillo-Cabanzo

Electronic Theses and Dissertations

Next generation semiconductor materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) are rapidly replacing Silicon (Si) for high power and high frequency applications due to Si’s inherent limitations. Despite the advantages of GaN over SiC, adoption of GaN has been hindered due to the lack of a cost-effective bulk production technique. Thus, the inability to precure native substrates requires GaN-based architectures to be heteroepitaxially synthesized on non-native substrates, such as sapphire and even SiC. This research seeks to develop a cost effective and scalable method to produce low defect, bulk GaN encouraging the adoption of GaN based devices …

Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides., Babajide Patrick Ajayi

Electronic Theses and Dissertations

Clean energy production and storage are two of the most significant challenges in the 21^st century currently limited by the discovery and development of new and advanced materials. Complex oxides and alloys made using earth-abundant elements will play a crucial role in technology development moving forward, however, current preparation techniques are limited by their inability to produce complex oxides and alloys with precise composition control at fast timescales. A concept was proposed to produce mixed metal oxides with composition control through the oxidation of liquid precursors via plasma oxidation. It was hypothesized that the oxidation process can be completed …

Experimental Investigation Of The Manufacture Of Tunable Graphene Oxide Filter Membranes Using Intense Pulse Light, Joshua H Kotter

Electronic Theses and Dissertations

Reduced graphene oxide is a thin, strong, and inexpensive material with a channel and pore structure that make it a promising candidate for a filtration material. Reduced graphene oxide has been produced and tested in the laboratory, but a lack of scalable manufacturing techniques have limited its commercial use.

This thesis has shown that graphene oxide can be rapidly manufactured with an industrially scalable flash reduction process. The flash reduction process uses 0.58 millisecond pulses from a xenon lamp to reduce the graphene oxide film in less than a minute. Results for partially reduced graphene oxide membranes tuned by the …

Characterization Of Microreactor And Analysis Of Carbonyl Compounds In Exhaled Breath., Qi Li

Electronic Theses and Dissertations

Analysis of trace volatile organic compounds at parts per billion (ppbv) to parts per trillion (pptv) level has become an important research frontier because of the applicability for environmental monitoring and noninvasive diagnosis of diseases. The methods of preconcentration for detection of trace aldehydes and ketones both in ambient air and human exhaled breath have increased considerably over the last decade. However, the majority of these methods are not efficient. In this dissertation, we have improved an innovative microreactor that is suitable for quantitative analysis of volatile carbonyl compounds (VOCs) in ambient air as well as in human exhaled breath. …