Chemical Engineering Commons^™

Functionalization Of Iron Oxide Nanoparticles And The Impact On Surface Reactive Oxygen Species Generation For Potential Biomedical And Environmental Applications, Trang Mai

Theses and Dissertations--Chemical and Materials Engineering

Iron oxide nanoparticles (IONPs) have been widely studied for a variety of applications, from biomedical applications (e.g., cell separation, drug delivery, contrast agent for magnetic resonance imaging and magnetically mediated energy delivery for cancer treatment) to environmental remediations (e.g., heavy metal removal and organic pollutants degradation). It has been demonstrated that IONPs can induce the production of reactive oxygen species (ROS) via Fenton/Haber-Weiss reactions which has been shown to be one of the key underlying mechanisms of nanoparticles toxicity. This inherent toxicity of nanoparticles has been shown to enhance the efficacy of traditional cancer therapies such as chemotherapy and radiation. …

Mechanical Properties And Degradation Of High Capacity Battery Electrodes: Fundamental Understanding And Coping Strategies, Yikai Wang

Theses and Dissertations--Chemical and Materials Engineering

Rechargeable lithium ion and lithium (Li) metal batteries with high energy density and stability are in high demand for the development of electric vehicles and smart grids. Intensive efforts have been devoted to developing high capacity battery electrodes. However, the known high capacity electrode materials experience fast capacity fading and have limited cycle life due to electromechanical degradations, such as fracture of Si-based electrodes and dendrite growth in Li metal electrodes. A fundamental understanding of electromechanical degradation mechanisms of high capacity electrodes will provide insights into strategies for improving their electrochemical performance. Thus, this dissertation focuses on mechanical properties, microstructure …

Cell Surface Coatings For Mammalian Cell-Based Therapeutic Delivery, Pei-Jung Wu

Theses and Dissertations--Chemical and Materials Engineering

The cell plasma membrane is an interactive interface playing an important role in regulating cell-to-cell, cell-to-tissue contact, and cell-to-environment responses. This environment-responsive phospholipid layer consisting of multiple dynamically balanced macromolecules, such as membrane proteins, carbohydrate and lipids, is regarded as a promising platform for various surface engineering strategies. Through different chemical modification routes, we are able to incorporate various artificial materials into the cell surface for biomedical applications in small molecule and cellular therapeutics.

In this dissertation, we establish two different cell coating techniques for applications of cell-mediated drug delivery and the localization of cell-based therapies to specific tissues. The …

Impact Of Conformational Change, Solvation Environment, And Post-Translational Modification On Desulfurization Enzyme 2'-Hydroxybiphenyl-2-Sulfinate Desulfinase (Dszb) Stability And Activity, Landon C. Mills

Theses and Dissertations--Chemical and Materials Engineering

Naturally occurring enzymatic pathways enable highly specific, rapid thiophenic sulfur cleavage occurring at ambient temperature and pressure, which may be harnessed for the desulfurization of petroleum-based fuel. One pathway found in bacteria is a four-step catabolic pathway (the 4S pathway) converting dibenzothiophene (DBT), a common crude oil contaminant, into 2-hydroxybiphenyl (HBP) without disrupting the carbon-carbon bonds. 2’-Hydroxybiphenyl-2-sulfinate desulfinase (DszB), the rate-limiting enzyme in the enzyme cascade, is capable of selectively cleaving carbon-sulfur bonds. Accordingly, understanding the molecular mechanisms of DszB activity may enable development of the cascade as industrial biotechnology. Based on crystallographic evidence, we hypothesized that DszB …

Targeted Illumination Strategies For Hydrogen Production From Purple Non-Sulfur Bacteria, John D. Craven

Theses and Dissertations--Chemical and Materials Engineering

The movement towards a more sustainable energy economy may require not only the generation of cleaner fuel sources, but the conversion of waste streams into value-added products. Phototrophic purple non-sulfur bacteria are capable of metabolizing VFAs (volatile fatty acids)and generate hydrogen as a byproduct of nitrogen fixation using energy absorbed from light. VFAs are easily produced from dark anaerobic fermentation of food, agricultural, and municipal wastes, which could then be fed into photobioreactors of purple bacteria for hydrogen production.

The process of photofermentation by purple bacteria for hydrogen production remains attractive due to the capability of reaching high substrate conversions …

Development Of Magnetic Nanocomposite Materials As Reusable Adsorbents For Chlorinated Organics In Contaminated Water, Angela Gutierrez

Theses and Dissertations--Chemical and Materials Engineering

The constant growth in population worldwide over the past decades continues to put forward the need to provide access to safe, clean water to meet human needs. There is a need for cost-effective technologies for water and wastewater treatment that can meet the global demands and the rigorous water quality standards and at the same maximizing pollutant efficiency removal. Current remediation technologies have failed in keeping up with these factors without becoming cost-prohibitive. Nanotechnology has recently been sought as a promising option to achieve these goals. The use of iron oxide magnetic nanoparticles as nanoadsorbents has led to a new …

Synthesis, Characterization And Applications Of Reduced Graphene Oxide And Composite Membranes For Selective Separations And Removal Of Organic Contaminants, Ashish Aher

Theses and Dissertations--Chemical and Materials Engineering

Among the next generation materials being investigated for membrane development, partially reduced Graphene Oxide (rGO) has received increasing attention from the membrane community. rGO-based nanofiltration membranes have shown promising results in applications such as partial desalination, organic contaminant removal, gas-phase separations, and separations from solvent media. rGO offers a unique platform compared to common polymeric membranes since it can be used for separation applications in both aqueous and organic solvent media. An rGO-based platform could also be utilized to synthesize reactive membranes, giving rGO membranes the additional capability of reactively removing organic contaminants. This research focuses on the synthesis of …

Nanoharvesting And Delivery Of Bioactive Materials Using Engineered Silica Nanoparticles, Md Arif Khan

Theses and Dissertations--Chemical and Materials Engineering

Mesoporous silica nanoparticles (MSNPs) possess large surface areas and ample pore space that can be readily modified with specific functional groups for targeted binding of bioactive materials to be transported through cellular barriers. Engineered silica nanoparticles (ESNP) have been used extensively to deliver bio-active materials to target intracellular sites, including as non-viral vectors for nucleic acid (DNA/RNA) delivery such as for siRNA induced interference. The reverse process guided by the same principles is called “nanoharvesting”, where valuable biomolecules are carried out and separated from living and functioning organisms using nano-carriers. This dissertation focuses on ESNP design principles for both applications. …

The Fabrication And Characterization Of Metal Oxide Nanoparticles Employed In Environmental Toxicity And Polymeric Nanocomposite Applications, Matthew Logan Hancock

Theses and Dissertations--Chemical and Materials Engineering

Ceria (cerium oxide) nanomaterials, or nanoceria, have commercial catalysis and energy storage applications. The cerium atoms on the surface of nanoceria can store or release oxygen, cycling between Ce³⁺ and Ce⁴⁺, and can therefore act as a therapeutic to relieve oxidative stress within living systems. Nanoceria dissolution is present in acidic environments in vivo. In order to accurately define the fate of nanoceria in vivo, nanoceria dissolution or stabilization is observed in vitro using acidic aqueous environments.

Nanoceria stabilization is a known problem even during its synthesis; in fact, a carboxylic acid, citric acid, is …

Overview Of Homechem: House Observations Of Microbial And Environmental Chemistry, Delphine K. Farmer, Marina E. Vance, Jon P. D. Abbatt, Andrew Abeleira, Michael R. Alves, Richard Corsi, Peter F. Decarlo, Allen H. Goldstein, Vicki H. Grassian, Lea Hildebrandt Ruiz, Jose L. Jimenez, Tara Kahan, Multiple Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

The House Observations of Microbial and Environmental Chemistry (HOMEChem) study is a collaborative field investigation designed to probe how everyday activities influence the emissions, chemical transformations and removal of trace gases and particles in indoor air. Sequential and layered experiments in a research house included cooking, cleaning, variable occupancy, and window-opening. This paper describes the overall design of HOMEChem and presents preliminary case studies investigating the concentrations of reactive trace gases, aerosol particles, and surface films. Cooking was a large source of VOCs, CO2, NOx, and particles. By number, cooking particles were predominantly in the ultrafine mode. Organic aerosol dominated …

Accumulation Of Di-2-Ethylhexyl Phthalate From Polyvinyl Chloride Flooring Into Settled House Dust And The Effect On The Bacterial Community, Samantha Velazquez, Chenyang Bi, Jeff Kline, Susie Nunez, Richard Corsi, Ying Xu, Suzanne L. Ishaque

Mechanical and Materials Engineering Faculty Publications and Presentations

Di-2-ethylhexyl phthalate (DEHP) is a plasticizer used in consumer products and building materials, including polyvinyl chloride flooring material. DEHP adsorbs from material and leaches into soil, water, or dust and presents an exposure risk to building occupants by inhalation, ingestion, or absorption. A number of bacterial isolates are demonstrated to degrade DEHP in culture, but bacteria may be susceptible to it as well, thus this study examined the relation of DEHP to bacterial communities in dust. Polyvinyl chloride flooring was seeded with homogenized house dust and incubated for up to 14 days, and bacterial communities in dust were identified at …

Optimization And Cost Comparison Of Reactor Types In A Styrene Production Process, Claire Lenore Cozadd

Honors Theses

The focus of this thesis is to use the equivalent annual operating costs of isothermal, adiabatic, and packed bed reactors in order to determine which reactor is most cost effective in a styrene production process. In order to understand the steps leading up to this comparison, background information is first given regarding chemical engineering design, optimization, and process simulation. This information was necessary for completing the ChE 451 design project, which was to analyze the base case styrene process before optimizing it, in fall 2018. The results of this project are briefly outlined in the second section. The third section …

Discrete Optimization Of A Styrene Production Process, Seth Gray

Honors Theses

This thesis will outline the two phases of my capstone design project for Chemical Engineering. The first goal was to simulate a styrene production process in Excel alongside my group members in ChE 451. During this phase, we looked at startup of the process and the first 12 years of operation. After the base case which included an isothermal reactor, the decision was made to switch to an adiabatic reactor based on net present value evaluations. Discrete optimization took place on the adiabatic reactor and the subsequent process. The second phase of my capstone project was the portion assigned to …

Techno-Economic Optimization And Environmental Life Cycle Assessment Of Microgrids Using Genetic Algorithm And Artificial Neural Networks, Prashant Nagapurkar

Doctoral Dissertations

"This dissertation focuses primarily on techno-economic optimization and environmental life cycle assessment (LCA) of sustainable energy generation technologies. This work is divided into five papers. The first paper discusses the techno-economic optimization and environmental life cycle assessment of microgrids located in the USA using genetic algorithm. In this paper, a methodology was developed that assessed the techno-economic and environmental performance of a small scale microgrid located in US cities of Tucson, Lubbock and Dickinson. Providing uninterrupted power the microgrid was composed of seven components -- solar photovoltaics, wind-turbines, lead acid batteries, biodiesel generators, fuel cells, electrolyzers and H₂ tanks. …

Studies Related To Chemical Changes In Biochar. I. Polyacrylonitrile Internal Standard To Assess Chemical Changes In Graphene Oxide. Ii. Ultrasonic Effects On Polycyclic Aromatic Hydrocarbons As Models For Biochar, Kaci B. Crawford

Honors Theses

Biochar has become an increasing area of research due to its reactive edges from stacks of graphene clusters. One particular area of interest in biochar is because it is a potent soil amendment which reduces soil acidity and can reduce greenhouse gas emissions from plants. Also, chemically-modified biochar is being studied as a carbon storage method to potentially mitigate climate change. In order to understand the chemistry that takes place on biochar’s reactive edges during modification, a standard is essential. This research attempted to identify an internal standard that could be added to biochar samples to quantify chemical changes by …

Effects Of Seawater On Carotenoid Production And Lipid Content Of Engineered Saccharomyces Cerevisiae, Yuqi Guo, Shangxian Xie, Joshua Yuan, Katy Kao

Faculty Publications

The use of seawater in fermentation can potentially reduce the freshwater burden in the bio-based production of chemicals and fuels. We previously developed a Saccharomyces cerevisiae carotenoids hyperproducer SM14 capable of accumulating 18 mg g−1 DCW (DCW: dry cell weight) of β-carotene in rich media (YPD). In this work, the impacts of seawater on the carotenoid production of SM14 were investigated. When using nutrient-reduced media (0.1× YNB) in freshwater the β-carotene production of SM14 was 6.51 ± 0.37 mg g−1 DCW; however in synthetic seawater, the production was increased to 8.67 ± 0.62 mg g−1 DCW. We found that this …

Ethanol Dehydration Over Wo3/Tio2 Catalysts Using Titania Derived From Sol-Gel And Solvothermal Methods With Palladium Modification, Anchale Tresatayawed

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, the characteristics and catalytic activity of WO3/TiO2 prepared by sol-gel and solvothermal and their metal modified were investigated. The research was divided into two parts. In the first part, the catalyst performance of WO3/TiO2 catalysts using titania derived from sol-gel and solvothermal methods over ethanol dehydration reaction was examined. The results showed that the different preparation methods essentially altered the physicochemical properties of TiO2 supports. It revealed that the titania derived from solvothermal method denoted as TiO2-SV exhibited higher surface area and pore volume, and larger amounts acid sites than the one obtained from sol-gel method (TiO2-SG). …

Development Of Bioplastic Blown Films To Be Used As A Packaging For Dried Banana, Apinya Wongthanaroj

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to study effects of poly(butylene adipate-co-terephthalate) (PBAT) contents on properties of polylactic acid / poly(hydroxybutyrate-co-hydroxyvalerate) / poly (butylene adipate-co-terephthalate) (PLA/PHBV/PBAT) blends to be used as a packaging for solar-dried bananas. The blend of PLA and PHBV (PLA/PHBV) was fixed at weight ratio of 80/20 while the PBAT content was varied from 0-30 wt%. The films were prepared by melt compounding and blown film extrusion. It was found that the addition of PBAT decreased barrier properties of PLA/PHBV film. Gas barrier which is oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) increased with increasing of PBAT …

Production Of Activated Carbonaceous Catalyst For Their Application In Bio Jet-Fuel Synthesis, Araya Smuthkochorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Recently, research and development in alternative aviation fuel to replace fossil-based fuel has been of interest for many research works. Hydrodeoxygenation (HDO) is one of the most efficient processes to produce clean fuel. This study involves the synthesis of activated carbon (AC) from heavy fuel oil (HFO) via the carbonization-chemical activation process for utilization as catalyst support. AC with a high surface area of 1527.4 m2/g was obtained from KOH-activation in the ratio of 1:1 and carbonization temperature of 700°C. The molybdenum phosphide (MoP) catalyst impregnated on AC was prepared via the wet impregnation process. The microscopic analysis revealed the …

Solar Energy Management System For Stand-Alone Application : Analysis Of Power Management Strategies Under Different Solar Irradiance Profiles, Chacrit Lerdwithayaprasit

Chulalongkorn University Theses and Dissertations (Chula ETD)

Clean power generation from various renewable energy sources has been gaining much attention due to sustainable and environmental reasons. As renewable energy sources and power demand vary, a hybrid power system and proper energy management are required. This study is focused on the development of an energy management system (EMS) in the hybrid renewable energy system consisting of photovoltaic cell (PV), proton exchange membrane fuel cell (PEMFC), and proton exchange membrane electrolysis cell (PEMEC). A vanadium redox flow battery (VRFB) as energy storage for long-term operation is integrated into such a hybrid system. The models of each subsystem are developed …