Digital Commons Network^™

Interfacial Chemistry Involved In Selective Separation Of Nmc/Lmo And Lco/Lmo Binary Cathode Materials By Froth Flotation Using Oleic Acid, Richard Kofi Oboh, Kaiwu Huang, Seoung Bum Son, Lei Pan

Michigan Tech Publications

The variability in cathode compositions within recycled lithium-ion battery (LIB) feedstocks poses a significant challenge to efficient downstream refining processes. This study demonstrates the feasibility of using froth flotation with oleic acid as a collector to selectively separate lithium nickel-manganese-cobalt oxide (NMC) and lithium cobalt oxide (LCO) from lithium manganese oxide (LMO) materials. Laboratory-scale flotation tests achieved an 80% separation efficiency in a single stage, producing a froth product with >90% purity of NMC/LCO at approximately 90% yield. Concurrently, the LMO materials were enriched in the sink product with ∼90% purity and ∼90% yield. This approach was further validated using …

Vacuum Consistent Electrochemistry In Ionic Liquid Combined With Oxide Epitaxy, Yuji Matsumoto

Journal of Electrochemistry

We introduce our state-of-the art of “vacuum consistent electrochemistry” to an investigation of the interfaces between oxides and ionic liquid (IL). Pulsed laser deposition (PLD) has been one of the powerful and sophisticated techniques to realize nanoscale preparation of high-quality epitaxial oxide thin films. On the other hand, electrochemistry is a simple, very sensitive, and non-destructive analysis technique for solid-liquid interfaces. To ensure the reproducibility in experiment of the interfaces of such epitaxial oxide films, as well as bulk oxide single-crystals, with IL, we employ a home-built PLD-electrochemical (EC) system with IL as an electrolyte. The system allows one to …

Valorization Of Date Palm Waste For The Isolation, Characterization, And Surface Chemistry Modification Of Nanocellulose, Mohsin Raza

Dissertations

This dissertation focuses on the utilization of date palm waste, a lignocellulosic material, as a source for the extraction of nanocellulose (NC), a versatile biopolymer with applications in biodegradable composites, bioplastics, and food packaging. Conventional methods of NC production using mineral acids such as sulphuric and hydrochloric acid are reaching their limits of toxicity, so more environmentally friendly alternatives such as ionic liquids (ILs) are being explored. The research focuses on the characterization of different date palm wastes to evaluate their α−cellulose content, lignocellulosic character, and thermal stability. By comparing extraction methods with mineral acids and ILs, the study evaluates …

Protein A And Multimodal Anion-Exchange Membrane Adsorbers For Downstream Purification Of Therapeutic Biomolecules, Joshua Osuofa

All Dissertations

This dissertation explores development and characterization of membrane chromatography tools for downstream purification of therapeutic biomolecules. Convective technologies, particularly membrane chromatography, are emerging in the field of bioseparations as an alternative to resin chromatography due to their improved throughput capability. On the forefront of emerging membrane technologies are multimodal and Protein A membrane adsorbers. The overarching theme of this dissertation research was to investigate advances in these membrane chromatography tools. The primary objective was to develop and characterize novel Protein A membrane adsorbers. A secondary objective was to characterize newly commercialized Protein A and multimodal anion exchange membrane adsorbers.

Two …

Optimization Of E-Textiles For Lactic Acid Detection, Andrew Laboy, Mallory David

Williams Honors College, Honors Research Projects

The overall goal of the project is to develop an e-textile that will be able to determine different characteristics of an athlete's health through multiple sensors. The goal of these sensors is to monitor physiological parameters for health and fitness uses in real time. Building from the existing sodium concentration sensor, these new sensors will detect lactate levels within sweat to monitor instantaneous health which allows customization of workout and overall health regimen.

Effectiveness Evaluation Of Fluorescent Tracer In Shaly-Sandstone Reservoir, Harid Pataveepaisit

Chulalongkorn University Theses and Dissertations (Chula ETD)

In petroleum exploration and production industry, tracer is a compound added to injected fluids, and can be easily detected even in a trace amount. Fluorescein sodium, a chemical tracer that can illuminate upon receiving a specific wavelength of light, was mentioned by several literatures due to its strong fluorescence at low concentration, non-toxicity, and non-biodegradability. In this study, fluorescein sodium in the form of fluorescein solution was evaluated with shaly-sandstone to observe their interactions. The first half of this study focused on the evaluation of the chemical characteristics of fluorescein. First, the detection limit of fluorescein solution in deionized water …

Reverse Flotation Separation Of Fluorite From Calcite: A Novel Reagent Scheme, Jianjun Wang, Zihan Zhou, Yuesheng Gao, Wei Sun, Yuehua Hu, Zhiyong Gao

Michigan Tech Publications, Part 1

Fluorite (CaF₂), as an important strategic mineral source, is usually separated from calcite by the common froth flotation method, but this separation is still not selective enough. The development of a selective collector and/or depressant is the key to achieving high selective separation. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP or H₄L) is widely used as an environmentally friendly water treatment reagent due to its low cost and excellent anti-scaling performance in an aqueous solution. In this study, a novel reagent scheme was developed using HEDP as a fluorite depressant and sodium oleate (NaOL) as a calcite collector for the …

Surface Chemisty Study Of Monazite Flotation In Coal Refuse Systems, Wencai Zhang

Theses and Dissertations--Mining Engineering

Rare earth mineral recovery from alternative resources such as coal and coal byproducts is increasingly important to provide an opportunity for economic recovery from U.S. sources. Currently, China produces the majority of the 149,000 tons of rare earth elements used annually worldwide of which the U.S. imports 11% or around 16,000 tons. There are no significant mining operations producing rare earth elements in the U.S. However, there are many U.S. sources containing rare earth minerals such as monazite including heavy mineral sand and phosphate operations. Monazite mineral particles of a few microns have also been detected in Fire Clay seam …

Development And Implementation Of Problem-Based Chemistry Experiments For Engineering Students In A Multi-Disciplinary Course, Tiffany Hesser, Stephanie R. Bunyea

Chemistry and Chemical Engineering Faculty Publications

This paper will describe the implementation and continuing development of five problem based laboratory experiments in a general chemistry course designed specifically for multiple disciplines of engineering students at the University of New Haven. The Problem Based Laboratory Experiments (PBLE) were developed to provide students with the opportunity to perform and develop experimental procedures working in interdisciplinary teams, while achieving a greater understanding of the role of chemistry in engineering fields. In each PBLE, students first complete a traditional chemistry experiment to gain an understanding of the chemical concepts and to become familiar with executing a written procedure with a …

Force Field Development With Gomc A Fast New Monte Carlo Molecular Simulation Code, Jason Richard Mick

Wayne State University Dissertations

In this work GOMC (GPU Optimized Monte Carlo) a new fast, flexible, and free molecular Monte Carlo code for the simulation atomistic chemical systems is presented. The results of a large Lennard-Jonesium simulation in the Gibbs ensemble is presented. Force fields developed using the code are also presented. To fit the models a quantitative fitting process is outlined using a scoring function and heat maps. The presented n-6 force fields include force fields for noble gases and branched alkanes. These force fields are shown to be the most accurate LJ or n-6 force fields to date for these compounds, capable …

Molecular Modeling Of Sigma 1 And Sigma 2 Receptor Ligands: Pharmacophore Development And Comparison Using Discotech And Bioactivity Prediction Comparison Of Ab Initio And Density Functional Comfa Studies For Spiro And Other Receptor Ligands, Lisa M. Kardos

Dissertations

The role of the biological receptor is currently being studied by researchers in medicine. Information about sigma receptors in particular can be gained by studying the ligands associated with each type, sigma 1 or sigma 2. Sigma 1 receptor ligands consist of drug candidates that often have psychiatric and neurological applications; sigma 2 receptor ligands consist of drug candidates that have been linked with cancer treatment among other applications.

Molecular modeling of biological receptor ligands often encompasses pharmacophore development and Comparative Molecular Field Analysis (CoMFA). Pharmacophore models are developed to understand the unique features such as binding groups that make …

Exploring The Use Of Faded Worked Examples As A Problem Solving Approach For Underprepared Students, Tiffany Hesser, Jess L. Gregory

Chemistry and Chemical Engineering Faculty Publications

It is not uncommon for students to find themselves underprepared when entering a post secondary institution. In additional to lower levels of academic achievement, underprepared students may not be aware that they lack the skills needed to be successful and effectively acquire and process information. Because of this, students that enter post-secondary institutions underprepared often require more support in and out of the college classroom.

In computational based classes, such as math, engineering, chemistry or physics, this support often includes an introduction to effective problem solving strategies. This study introduced faded worked examples as a problem solving approach to students …

Kinetic Experimental And Modeling Studies On Iron-Based Catalysts Promoted With Lanthana For The High-Temperature Water-Gas Shift Reaction Characterized With Operando Uv-Visible Spectroscopy And For The Fischer-Tropsch Synthesis, Basseem Bishara Hallac

Theses and Dissertations

The structural and functional roles of lanthana in unsupported iron-based catalysts for the high-temperature water-gas shift reaction and Fischer-Tropsch synthesis were investigated. The performance of the catalysts with varying lanthana contents was based on their activity, selectivity, and stability. With regard to the former reaction, extent of reduction of the iron in Fe2O3/Cr2O3/CuO/La2O3 water-gas shift catalysts is a key parameter that was characterized using UV-visible spectroscopy. Minor addition of lanthana (<0.5 wt%) produces more active and stable catalysts apparently because it stabilizes the iron-chromium spinel, increases the surface area of the reduced catalysts, enhances the reduction of hematite to the magnetite active phase, and facilitates the adsorption of CO on the surface of the catalyst modeled by an adsorptive Langmuir-Hinshelwood mechanism. Statistical 95% confidence contour plots of the adsorption equilibrium constants show that water adsorbs more strongly than CO, which inhibits the reaction rate. A calibration curve that correlates the oxidation state of surface iron domains to normalized absorbance of visible light was successfully generated and applied to the water-gas shift catalysts. UV-visible studies indicated higher extent of reduction for surface Fe domains for the catalysts promoted with 1 wt% of lanthana and showed potential to be a more convenient technique for surface chemistry studies than X-ray absorption near edge spectroscopy (XANES). Lanthana addition to iron-based Fischer-Tropsch catalysts enhances the olefin-to-paraffin ratio, but decreases their activity, stability, and selectivity to liquid hydrocarbons. Adding lanthana at the expense of potassium reduces the water-gas shift selectivity and enhances the activity and stability of the catalysts. Finally, a model that simulates heat and mass transfer limitations on the particle scale for the Fischer-Tropsch reaction applicable at lab-scale suggests optimal operating and design conditions of 256°C, 30 bar, and 80 mirons are recommended for higher selectivity to liquid hydrocarbons. The model considers pressure drop, deactivation, pore diffusion, film heat transfer, and internal heat transfer when solving for the optimal conditions, and maps them as functions of design variables. This model can be up-scaled to provide guidance for optimal design of commercial-size reactors.

Stabilizing Nanostructured Solid Oxide Fuel Cell Cathode With Atomic Layer Deposition, Yunhui Gong, Diego Palacio, Xueyan Song, Rajankumar L. Patel, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

We demonstrate that the highly active but unstable nanostructured intermediate-temperature solid oxide fuel cell cathode, La_0.6Sr_0.4CoO_3-δ (LSCo), can retain its high oxygen reduction reaction (ORR) activity with exceptional stability for 4000 h at 700 C by overcoating its surfaces with a conformal layer of nanoscale ZrO₂ films through atomic layer deposition (ALD). The benefits from the presence of the nanoscale ALD-ZrO₂ overcoats are remarkable: a factor of 19 and 18 reduction in polarization area-specific resistance and degradation rate over the pristine sample, respectively. The unique multifunctionality of the ALD-derived nanoscaled ZrO₂ overcoats, …

Robust Methods For Construction Of Global Potential Energy Surfaces, Phalgun Lolur

Masters Theses

"This thesis is about the development of robust methods for construction of global potential energy surfaces to study the spectroscopy and dynamics of molecular systems. A potential energy surface represents the electronic energy of a molecule as a function of its geometry. This is central to how chemists view molecular systems in terms of motion across a rich energy landscape where barriers separate wells corresponding to different stable structures. The range of molecular distortions defines the potential energy surface. Computing the potential energy surface of a molecule has become a fundamental operation in modern theoretical chemistry studies. The Born-Oppenheimer approximation …

Effect Of Freshman Chemistry On Student Performance In Sophomore Engineering Courses, Michael A. Collura, Shannon Ciston, Nancy Ortins Savage

Chemistry and Chemical Engineering Faculty Publications

The role of first year chemistry courses in engineering programs varies somewhat across programs and disciplines. Clearly most engineering majors will encounter chemistry topics of a general nature in some of their upper-level course work. The purpose of requiring chemistry in the first year, however, goes well beyond learning chemical concepts. As a quantitative science, chemistry requires the use of math, principally algebra, on a regular basis in solving various problems. Students should gain an appreciation of the importance of units in solving problems should come to understand the difference between implicit and explicit properties and should develop other quantitative …

Web Based Classes For Enhancement Of Prelaboratory Lectures, Tiffany Hesser, Michael Collura

Chemistry and Chemical Engineering Faculty Publications

The use of web classes, such as Tegrity Campus1, as a supplement to pre laboratory reading or a replacement for pre laboratory lectures could become a standard tool in laboratory education protocol. In classes with multiple lab sections and instructors, pre laboratory lectures can lack consistency and it can be difficult to gauge the students’ level of preparation. With the ever increasing exposure to technology, students generally prefer information in a digital and multimedia form, rather than textbook readings. Therefore, this method can prove to better prepare students prior to laboratory experiments, increasing the overall understanding of the chemical reactions …

Introduction To Pollution Prevention Concepts In Freshman Chemistry Through Simulations And Hypermidia, Aniraban Bhaumik

Theses

As citizens of the 20th century, a key issue we all are aware of is degradation of the environment. In the interest of teaching the environmental issues to freshmen engineers, this study develops a computer aided learning/teaching (CAL/T) tool.

This CAL/T tool consists of Internet based multimedia courseware and intelligent simulations. The courseware assembles the fundamentals of chemistry associated with current environmental issues such as air pollution, stratospheric ozone layer depletion and environmentally sensitive or 'clean' manufacturing. The courseware targets early and comprehensive understanding of pollution prevention concepts with a focus on environmentally friendly manufacturing. The courseware includes: on-line text, …

Influence Of Formation Processes On Oblique Detonation Wave Stabilization, K. Ghorbanian, J. D. Sterling

Business and Information Technology Faculty Research & Creative Works

In this article we report steady, two-dimensional, inviscid solutions for the near field and far field of a supersonic reactive flow over a variable-double-ramp geometry. The incident shock wave compresses and heats the reactants that will combust after flowing some induction length. Upon reaction, a detonation wave forms and intersects the leading wave at some distance from the ramp surface. In this article, reaction-polar diagrams are developed, and the detonation branch solutions are used to investigate the wave interaction processes that may lead to a steady three-wave structure. By considering this formation process new oblique detonation wave stabilization criteria based …