Other Chemical Engineering Commons^™

Interfacial Phenomena Of Plastics: From Surface Modifications To Environmental Impacts, Kennedy Guillot

LSU Doctoral Dissertations

Plastic is a ubiquitous part of everyday life since its introduction in the previous century. Global production continues to exponentially increase, establishing plastics as one of the most dominant materials in modern manufacturing. Within the scope of academia, plastic is essential due to its low cost and sterility, particularly for minimizing contamination. Beyond the laboratory, plastic use spans numerous industries, and its use and disposal has since raised many environmental concerns. Once valued for its durability, plastics now pollute the environment in landfills and natural ecosystems. In recent decades, the consequences of this pollution have been investigated, yet the full …

The Fabrication Of Nearly Monodisperse Chiral And Achiral Plasmonic Nanostructures And Their Applications, Macayla J. Caso

LSU Doctoral Dissertations

An object is chiral when it holds no lines of symmetry. This quality naturally occurs in chemistry and biology. When an object is chiral it has a unique handedness and objects of opposite chirality are called enantiomers. The importance of handedness was brought to light in the 1960’s when a racemic mixture of thalidomide enantiomers was given to pregnant women. One enantiomer was able to treat morning sickness while the other caused severe birth defects. This case brought to light how enantiomers have unique properties from each other even though they are similar materials. With this knowledge chiral nanomaterials must …

Phase Transitions And Photoluminescent Properties Of Anion-Engineered Y2o3, Maharram Jabrayilov

LSU Master's Theses

Rare earth doped metal oxides are widely employed as phosphor materials for white light LEDs (w-LEDs). The aim of this work is to engineer anionic sites of metal oxides, specifically, Y₂O₃, to investigate structural and luminescent properties relationships and energy transfer mechanisms between rare earth sensitizer and activator ions in different hosts.

A low temperature two-step hydrothermal/combustion method was employed to incorporate sulfate ions into Y₂O₃. Furthermore, annealing at 600 °C under H₂/N₂ was employed to convert Y₂O₂SO₄ to Y₂O₂S. …

Electric Field Driven Co-Assembly And Transport Of Colloids Using Active-Passive Interaction, Brishty Deb Choudhury

LSU Master's Theses

Over the past few decades, the out-of-equilibrium transport and assembly of colloidal particles have been drawing significant interest due to their myriad applications in biology, engineering, and physics. In the absence of any external force, micro and nanoparticles perform Brownian motion in dispersion and are termed as passive colloids. In contrast, active colloids are a class of particles where a net imbalance of fluid flow around their surface drives their net migration in space when subjected to an external electric field. While several studies have shown the ability to program the dynamics of active colloids using an external electric field, …

Heteroaggregation Of Lignin-Zein Nanoparticles: Effects Of Relative Size And Concentration, Yada Chulakham

LSU Master's Theses

Nanotechnology has become an advanced tool for manufacturing materials of the future. As the size of a material is reduced to a nanoscale, its surface area to volume ratio increases drastically, and its surface property becomes size dependent. This allows scientists to make use of unique properties that nanomaterials have to offer to create novel materials that otherwise could not have been achieved in meter-scale materials. As more industrial companies have planned to incorporate different types of nanomaterials into their products, it is undeniable that some of these nanomaterials will be released to the environment. Such possibility has led to …

Adsorption And Transport Of Colloids At Interface And In Bulk, Jingyun Lee

LSU Doctoral Dissertations

Colloids are suspensions of microscopic insoluble particles dispersed in a continuum phase such as liquid or gas. Colloids are found in our everyday life from food and cosmetic industries to pharmaceutical and biomedical applications. Depending on a global minimum of the free-energy landscape, colloidal suspensions can be classified as two major classes: equilibrium or active colloidal system. This Ph.D dissertation presents strategies to engineer equilibrium self-assembled structures and out-of-equilibrium active matter using various interparticle forces.

First, we introduce the means to promote the equilibrium self-assembled structures driven by adsorption of colloids at interface. Typically, adsorption of colloids at interface is …

Gold-Semiconductor Photocatalysts For Water Treatment Under Visible And Ultraviolet Light, Daniel Willis

LSU Doctoral Dissertations

Water scarcity threatens the lives of millions of people worldwide. It is imperative to improve the energy efficiency and affordability of water treatment methods to avoid a looming water-energy crisis. To meet this challenge, I have pursued research on the use of sunlight—our most reliable and abundant source of energy—to drive water treatment through photocatalysis. I explored the literature and found gold-semiconductor materials to hold promise for harvesting sunlight and catalyzing the breakdown of waterborne contaminants. Initially, I designed a novel optical cavity with gold (Au) nanoparticles on a zinc oxide / titania (TiO₂) / aluminum film stack …

Emulsion Templating Application For Synthesis Of A Porous Zein Biocompatible Oil Adsorbent, Nathan Holley

LSU Master's Theses

The recovery of spilled oil from water sources using hydrophobic porous absorbent has gained significant interest due to the ease of implementation, large-scale adaptability, and robust nature of the technique. However, the lack of biodegradability of these synthetic adsorbents has caused concern of further contaminating the environment from the generation of microplastic waste that is known to persist and accumulate in the marine food chain and other ecosystems. To mitigate this potential hazard, a new biocompatible alternative is needed to replace the non-degradable synthetic materials currently used. This thesis presents ZEin-based Low Density porous Absorbent (ZELDA), synthesized using a particle …

Adsorption And Reconfiguration Of Amphiphiles At Silica-Water Interfaces: Role Of Electrostatic Interactions, Van Der Waals Forces And Hydrogen Bonds, Yao Wu

LSU Doctoral Dissertations

The ability to explore and predict metastable structures of hybrid self-assemblies is of central importance for the next generation of advanced materials with novel properties. As compared to their thermodynamically stable forms, the kinetically stabilized materials show improved functionality potentially over their stable counterparts. The self-assembly processes usually originate from weak intermolecular interactions, involving a dynamic competition between attractive and repulsive interactions. These weak forces, including van der Waals (vdW), electrostatic interaction and the hydrogen bonding (H-bonding), can be tuned by external stimuli, e.g., confinement, temperature and ionization, and consequently driving hybrid materials into different configurations. It is challenging to …

Tunable Luminescence Of Rare Earth Doped Nanophosphors Via Adaptive Optical Properties Of Transition Metals, Pragathi Darapaneni

LSU Doctoral Dissertations

Over the past decades, the development of light-emitting diodes (LEDs) to produce a wide range of wavelengths has revolutionized the solid-state lighting industry due to their higher energy efficiency and operational lifetimes. These LEDs employ rare earth (RE) doped phosphors due to their stable emission wavelengths which can be amplified when sensitized by other RE dopants (Yb, Ce) or shell layer passivation. However, there has been a push to replace the RE elements in LEDs due to increased socioeconomic issues. One proposed alternative, transition metal (TM) dopants, is typically avoided due to their susceptibility to the local crystal environment resulting …

Noble-Transition Alloy Absorbers For Near-Infrared Hot-Carrier Optoelectronics, Sara Karoline Figueiredo Stofela

LSU Doctoral Dissertations

Optoelectronics is the field of technology concerned with the study and application of electronic devices that source, detect and control light. Here we focus on the optical communications field which relies on optical fiber systems to carry signals to their destinations operating in the near-infrared range. To improve the performance of current optical fiber systems, one of the paths is to develop better near-infrared photodetectors.

The current group of materials used for near-infrared photodetection relies in the III-V semiconductor family. Although their spectral photosensitivity correlates well with the near-infrared, response time performance and electronic circuit integration remain limited for this …

Breaking Coastal Hypoxia: Destratification Of Gulf Of Mexico Deadzone To Encourage Oxygen Transport Downwards To Maintain Marine Fauna, Veda Thipparthi

LSU Master's Theses

As a consequence of seasonal eutrophication and human input, a vast hypoxic area termed The Dead Zone develops every year in the Gulf of Mexico (GOM) during summer along the Louisiana coastline characterized by vertical seawater density-stratification with oxygen concentrations less than 2 mg.l^-1 at the seafloor. It poses a threat to bottom-dwelling faunae and their environment which has negative ecological and economic consequences. This project aims to mitigate hypoxia by employing mechanical impellers placed at strategic water depths and locations in the Gulf. Enhanced transport of oxygen results by mixing oxygen-enriched seawater at the surface, downward into the …

The Effects Of Temperature On The Yields Of Aliphatic And Aromatic Products From The Supercritical Pyrolysis Of 1-Octene, Elizabeth Anne Hurst

LSU Doctoral Dissertations

Prior to their combustion, fuels for future high-speed aircraft are expected to experience supercritical conditions, leading to the production of polycyclic aromatic hydrocarbons (PAH), precursors to solid carbonaceous deposits, via pyrolytic reactions. These solid deposits can clog fuel-transfer lines, causing unsafe aircraft operation. To prevent the formation of fuel-line deposits, it is critical to understand the reaction pathways that lead to PAH formation in the supercritical fuel pyrolysis environment.

To better understand the role of large 1-alkenes in PAH formation, supercritical pyrolysis experiments with model fuel 1-octene, a representative 1-alkene product from supercritical n-alkane pyrolysis, have been performed. The …