Chemical Engineering Commons^™

Recovery Of Degraded Ni-Rich Nmc811 Particles For Lithium-Ion Batteries, Han Yu, Yan Gao, James Kirtley, Gabriel Borgmeyer, Xiaoqing He, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Nickel-rich cathode materials attract a lot of attention due to their high energy density. However, their sensitivity to air and moisture hinders their practical applications. Exposing Ni-rich NMC in the air will produce by-products that are not conducive to lithium-ion transmission. Water washing can be used to remove by-products on the surface, but it can also introduce new problems, such as the generation of NiO on the particle surface, which will reduce the electrochemical performance of the material. In this study, Al₂O₃atomic layer deposition (ALD) was applied on degraded NMC811 particles to recover the electrochemical performance …

Fate And Transport Of Toxoplasma Gondii Oocysts In Saturated Porous Media: Effects Of Electrolytes And Natural Organic Matter, Christian Pullano

All Theses

Toxoplasma gondii is a pathogenic microorganism that is currently a threat to public health. Understanding the fate and transport of T. gondii through the soil and groundwater is vital in determining the risk it poses to water resources and human health. The physico-chemical interactions between the groundwater and the bio colloid within an aquifer will dictate its mobility and its ability to infect humans. This research examines how various naturally occurring groundwater chemistries containing organic compounds and monovalent and divalent salt solutions will alter the fate and transport of T. gondii. Solutions containing various concentrations of humic acid, fulvic …

Erythrocyte Deformability In Response To Glucose Using Liquid Crystals, Jayden Goff

Biomedical Engineering Undergraduate Honors Theses

The worldwide prevalence of diabetes mellitus is rapidly increasing with about 9.3% of the adult population living with the disease. People with diabetes have trouble regulating their blood glucose levels which typically leads to hyperglycemia. Under normal physiological conditions, erythrocytes can undergo deformations in response to shear stress when passing through capillaries with a smaller diameter. Poorly managed hyperglycemia can lead to the glycosylation of erythrocyte membrane proteins and hemoglobin. This glycosylation leads to increased rigidity of the cells along with decreased deformability in response to mechanical stress; therefore, these cells have a higher susceptibility of getting stuck in the …

Analyzing The Surface Chemistry Of Ni-Fe Hydroxide Alloy Nanoparticles As Catalysts For The Oxygen Evolution Reaction By X-Ray Photoelectron Spectroscopy Analysis, Lauren B. Shepard

Chemical Engineering Undergraduate Honors Theses

Water electrolysis has been proposed as a renewable source of hydrogen, a possible replacement to harmful fossil fuels. This process can be broken down into two half reactions, the hydrogen evolution reaction and the oxygen evolution reaction. Because the oxygen evolution reaction has slow kinetics and a high overpotential to overcome, a catalyst is needed to speed up the kinetics and ensure faster and more efficient production of molecular hydrogen. The use of Ni-Fe hydroxide alloy nanoparticles as a catalyst has been shown to significantly improve the efficiency of the reaction by decreasing the overpotential, making the process more energy …

Ultrafiltration Membranes Functionalized With Copper Oxide And Zwitterions For Fouling Resistance, Cannon Hackett, Mojtaba Abolhassani, Lauren Greenlee, Audie K. Thompson

Chemical Engineering Faculty Publications and Presentations

Polymeric membrane fouling is a long-standing challenge for water filtration. Metal/metal oxide nanoparticle functionalization of the membrane surface can impart anti-fouling properties through the reactivity of the metal species and the generation of radical species. Copper oxide nanoparticles (CuO NPs) are effective at reducing organic fouling when used in conjunction with hydrogen peroxide, but leaching of copper ions from the membrane has been observed, which can hinder the longevity of the CuO NP activity at the membrane surface. Zwitterions can reduce organic fouling and stabilize NP attachment, suggesting a potential opportunity to combine the two functionalizations. Here, we coated polyethersulfone …

Phonon Thermodynamics Of Bcc Zirconium With Machine Learning, Vanessa Judith Meraz

Open Access Theses & Dissertations

First principles-based simulations have allowed us to explore emerging phenomena in a variety of systems. Its steadfast practicality has led to an increase in molecular and materials design ranging from drug discovery to planetary formation. However ubiquitous in its field, one of its biggest drawbacks is its computational cost, notably so in molecular dynamics simulations. To counter this setback, there have been many leading efforts in machine learning methods, whether it be in algorithms or network architectures. Our contribution uses an active learning algorithm paired with a tensor field network, e3nn. By steadily feeding new data points to our model, …

Lithospheric Structure Underneath The Archean Tanzania Craton And Adjacent Regions From A Joint Inversion Of Receiver Functions And Rayleigh-Wave Phase Velocity Dispersion, Tuo Wang, Stephen S. Gao, Qiuyue Yang, Ling Chen, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Lithospheric structure beneath the Archean Tanzania craton and adjacent regions, including segments of the East African rift system (EARS) and the Proterozoic-early Paleozoic orogenic belts between the EARS and the craton, is imaged by a joint inversion of receiver functions and Rayleigh wave dispersion measurements derived from ambient seismic noise for shorter periods and teleseismic data for longer periods. Our resulting crustal thickness, crustal VP= VS measurements and 3D shear-wave velocity model for the upper 120 km show a clear spatial correspondence with major surficial geological features. The new results suggest the presence of a mafic layer in the bottom …

Development Of Porous Solid Acid Catalysts For Lignocellulose And Plastic Upcycling., Mohammad Shahinur Rahaman

Electronic Theses and Dissertations

My goal is to develop chemical processes for transforming waste to solve environmental problems and enhance sustainability. Environmental problems such as pollution and massive amounts of waste are the main drivers that stimulate my research ideas. I focused on creating novel, efficient catalytic processes for converting polymeric waste "feedstocks" into high-value chemicals by integrating my expertise in catalysis, materials science, and synthetic chemistry to develop porous solid catalytic materials. During my Ph.D., I focused on two polymeric feedstocks, lignocellulose, and discarded plastic.

Early in my Ph.D. journey, I focused on catalytic upcycling of lignocellulose. Lignocellulosic biomass is cost-effective, abundant, and …

Sanitary Ware Waste As A Source For A Valuable Biodiesel Catalyst, Mai H. Roushdy

Chemical Engineering

Biofuel is a type of fuel that is made from biomass using modern techniques rather than the relatively slow geological processes that lead to the development of fossil fuels. In Europe, biodiesel is the most widely used biofuel. The sanitary ware industry generates a lot of hazardous waste, such as waste gypsum molds. These molds are broken, pulverized, and reacted with NaCO3 to make CaCO3, which is then heated to produce CaO. The resulting CaO catalyzes the reaction between waste frying oil and methanol for biodiesel synthesis. To evaluate the effect of reaction parameters on the production of biodiesel, the …

Koh-Based Modified Solvay Process: Optimization And Kinetics Studies, Aya Abdel-Hamid Mourad

Dissertations

While desalination of seawater is important for meeting the water demand, the technology produces large volumes of reject brine and CO₂, causing environmental pollution. Solvay process (based on ammonia, NH₃) and modified Solvay process (based on calcium oxide, CaO) try to manage these wastes. However, more attention is needed to overcome different limitations of these processes such as, alkaline solubility, operating temperature, maintaining high pH value, and low sodium (Na⁺) removal efficiency, which does not exceed 35%. The aim of this work is to introduce an alternative alkaline, namely potassium hydroxide (KOH) and investigate …

A Compact Natural Gas Pyrolysis Reactor For Hydrogen Fueling Stations, Andrew Richard Earls

Theses and Dissertations

With the increasing amount of greenhouse gases causing more natural disasters and sea level rise, there is a clear need for a global energy transition to less polluting fuels. A possible solution to this problem is converting a portion of the transportation sector fuel to hydrogen. In this thesis, the issues associated with such a transition are discussed and reasonable solutions are proposed. Numerous methods of hydrogen production are explored and compared on the basis of electricity consumption and CO2 emission. A plant size of 1250 kg liq. H2/day is chosen based on California regulated hydrogen refueling credits (HRI) that …

Desalination Waste Revitalization Using Carbon Capture: Process Optimization Using Machine Learning, Ahmed Mohamed Elsayed

Theses

Over the next five to ten years, desalination will play an ever-important role in our society. Developing nations will look at desalination from the point of water scarcity, while developed nations will consider the perspective of the Water-Energy-Food nexus. With current technology, for every liter of freshwater produced, one and a half liters is thrown away as waste. This body of research proposes to employ chemical precipitation in ammoniated brine solutions, that have reasonably high ionic concentrations. CO2 absorption in Bubble Column Reactors can reduce sodium ions by precipitating NaHCO3. Also, the absorbed CO2 can reduce chloride ions and induce …

Membrane Bioreactor For Enhanced Enzymatic Hydrolysis Of Cellulose, Saleha Abdullah Al-Mardeai

Dissertations

With the rising environmental concerns related to fossil fuels utilization and the depletion of these resources, interest in bioethanol from lignocellulosic waste as an alternative, sustainable energy source has been increasing. Date palm waste is considered a good feedstock for bioethanol production, especially in countries of large date palm plantations, such as the United Arab Emirates.

In the lignocellulose to bioethanol process, the enzymatic hydrolysis of celluloses to produce simple sugars that can be converted to bioethanol by fermentation is the most challenging step, and enhancing it is essential for efficient and feasible operation. Enzyme inhibition by the products is …

Effects Of Continuous In Situ Low-Dose Ionizing Radiation On Microorganisms, Molly E. Wintenberg

All Dissertations

Precise detection and monitoring of nuclear fuel cycle, enrichment, and weapon development activities are critical for supporting warfighter preparation in chemical, biological, radiological, nuclear, and explosives (CBRNE) operations, clandestine activities, and nuclear compliance. A biological sensing system could serve as an alternative to traditional detection methods by using organic material naturally present in the environment to discreetly detect residual trace nuclear material. Microorganisms provide an optimal platform for an alternative sensing system; however, their response to low levels of ionizing radiation is poorly characterized. Combining the power of next-generation sequencing and transcriptomic analysis, this dissertation takes an approach to obtain …

Drug-Facilitated Sexual Assault At The University Of Arkansas, Barrett Weidman

Chemical Engineering Undergraduate Honors Theses

This work was written to fulfill two main purposes. First, to help survivors of Drug-Facilitated Sexual Assault (DFSA) process their experience by compiling the toxicological, pharmacological, and distribution of the three most used date-rape drugs. Second, to gauge the knowledge and interest of University of Arkansas students regarding drug impairments, sexual assault education, and bystander intervention training. A survey was conducted for the latter and revealed that 91.6% of students believe the University’s existing sexual assault prevention education and bystander intervention training have room for improvement. Also, 37.1% of students who have received this education report that the programming does …

Free Convection Heat Transfer From Plates, Alexa Moreno

Chemical Engineering Undergraduate Honors Theses

The purpose of this honors thesis is to create an experiment for the CHEG Lab I course. This report explains the motivation for creating this heat convection experiment, the results of performing the experiment, and provides recommendations for future work on this experiment. Multiple experiments were performed to assess materials and parameters to be investigated. It was determined that a 0.5” plate has smaller percent error and accommodates for the desired timeframe for a Lab I experiment compared to the first plate used (1.5” thickness). Recommendations for expanding on this project include adding experiments using vertical geometry for heat convection …

Quantification Of Slit-Like Pores Through Using Liquid Crystals As A Template, Dominique Savage

Chemical Engineering Undergraduate Honors Theses

The purpose of this research is to manufacture a membrane with slit-like pores to achieve particle filtration. Slit-like pore membranes are preferred over conventional membranes with cylindrical pores since slit-like pores have two length scales that can be manipulated to better control cut off and flux through the membrane. This project focuses on manufacturing slit-like pore membranes through the use of two liquid crystals, 1,4-bis[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene (RM257) and 4-Cyano-4′-pentylbiphenyl (5CB). This method for making slit-like pores has not been widely investigated nor has the morphology of the membrane pores and mechanical properties of such a membrane been addressed. It was found …

Synthesis And Phase Transition Characterization Of Liquid Crystal Membranes With Slit-Like Pores, Isaac Hopwood

Chemical Engineering Undergraduate Honors Theses

Membranes with slit-like pores have been of interest for some time due to their ability to reject smaller particles than traditional cylindrical-pored membranes at the same fluid flux. However, using liquid crystals as a template for this sort of membrane has not been thoroughly investigated. In this study, the liquid crystal mixture of RM257 (2-Methyl-1,4-phenylene bis(4-(3-(acryloyloxy)propoxy)benzoate)) and 5CB (4-Cyano-4'-pentylbiphenyl) for the purpose of manufacturing membranes with slit-like pores, the phase transition behavior of this LC mixture at various mole fractions of RM257, and the impact of mole fraction of RM257 in the liquid crystal (LC) mixture and membrane manufacturing conditions …

Diffusion Of A Salt In An Aqueous Media, Aldaly Pineda Hernandez

Chemical Engineering Undergraduate Honors Theses

Diffusion is defined as the net transfer of a molecule from a high concentration region to a low concentration region. The concept of diffusion is used in a very important process called "desalination." Desalination is a separation process used to reduce the salt content dissolved in brackish water to make it suitable for human consumption, irrigation, and industrial use.

In desalination plants, it is important to monitor the constantly changing salt content of water, partly due to the diffusive effect. The main purpose of this experiment was to study the diffusion of NaCl in water at two NaCl concentrations. The …

Extractive Membranes For The Detection And Screening Of Waterborne Plutonium, James Foster

All Dissertations

The development of rapid screening tools for special nuclear materials remains a crucial focus for nonproliferation efforts. Traditional approaches for the analysis of trace-level Pu isotopes in water requires tedious and time-consuming sample preparation steps that do not lend well to expeditious screening. Therefore, a novel analytical method that combines both Pu concentration and source preparation into a single detection system would make for an invaluable tool for nuclear security applications. Extractive membranes absorbers can help to fulfill this role as they are capable of concentrating Pu to detectable limits while subsequently serving as alpha spectrometry sample sources. In Chapter …