Chemistry Commons^™

Selective Oxidation Of Alkenes In Air Catalyzed By Mn3o4 Nanoparticles, Brojo Kishor Shachib Dhali

Dissertations and Theses

Catalytic oxidation is a process where compounds are oxidized using catalysts. Solid catalysts exhibit several advantages over homogeneous systems, such as catalyst recovery and excellent stability. Various supported transition-metal oxides (for example: CuO, ZnO, CeO2, Fe2O3 and WO3), metal nanoparticles (for example: Pd and Ru) and polyoxometalate clusters (for example: [W10O32]4-, [Mn2ZnW(ZnW9O34)2]10- and [XW12O40]n- (X = P, Si)) have been applied to selective oxidation of organic compounds, but high associated product conversion still remains a challenge. Recently, a number of materials containing Mn3O4 have been used successfully in different catalytic applications, such as degradation of phenols, reduction of nitrobenzenes, and …

Ultrasound-Driven Fabrication Of Nanosized High-Entropy Materials For Heterogeneous Catalysis, Francis Uchenna Okejiri

Doctoral Dissertations

High-entropy materials (HEMs) have emerged as a new class of multi-principal-element materials with great technological prospects. As a unique class of concentrated solid-solution materials, HEMs, formed on the premise of incorporating five or more principal elements into a single crystalline phase, provide an excellent opportunity to access superior catalytic materials ‘hiding’ in the unexplored central regions of a multicomponent phase space of higher orders.

However, the fabrication of HEMs is energy-intensive, typically requiring extreme temperatures and/or pressures under which agglomeration of particles occurs with a commensurate decrease in surface area. For most catalytic applications, non-agglomerated particles with high surface areas …

Premade Nanoparticle Films For The Synthesis Of Vertically Aligned Carbon Nanotubes, Abdul Hoque, Ahamed Ullah, Beth S. Guiton, Noe T. Alvarez

Chemistry Faculty Publications

Carbon nanotubes (CNTs) offer unique properties that have the potential to address multiple issues in industry and material sciences. Although many synthesis methods have been developed, it remains difficult to control CNT characteristics. Here, with the goal of achieving such control, we report a bottom-up process for CNT synthesis in which monolayers of premade aluminum oxide (Al₂O₃) and iron oxide (Fe₃O₄) nanoparticles were anchored on a flat silicon oxide (SiO₂) substrate. The nanoparticle dispersion and monolayer assembly of the oleic-acid-stabilized Al₂O₃ nanoparticles were achieved using 11-phosphonoundecanoic acid …

Enhanced Platinum (Ii) Drug Delivery For Anti-Cancer Therapy, Marek T. Wlodarczyk

Dissertations, Theses, and Capstone Projects

Over the years, anti-cancer therapies have improved the overall survival rate of patients. Nevertheless, the traditional free drug therapies still suffer from side effects and systemic toxicity, resulting in low drug dosages in the clinic. This often leads to suboptimal drug concentrations reaching cancer cells, contributing to treatment failure and drug resistance. Among available anti-cancer therapies, metallodrugs are of great interest. Platinum (II)-based agents are highly potent and are used to treat many cancers, including ovarian cancer (OC). Cisplatin (cis-diaminedichloroplatinum (II)) is the first Food and Drug Administration (FDA)-approved metallodrug for treatment of solid tumors, and its mechanism …

Heteroacene-Based Amphiphile As A Molecular Scaffold For Bioimaging Probes, Tharindu A. Ranathunge, Mahesh Loku Yaddehige, Jordan H. Varma, Cameron Smith, Jay Nguyen, Iyanuoluwani Owolabi, Wojciech Kolodziejczyk, Nathan I. Hammer, Glake Hill, Alex Flynt, Davita L. Watkins

Faculty Publications

The challenges faced with current fluorescence imaging agents have motivated us to study two nanostructures based on a hydrophobic dye, 6H-pyrrolo[3,2-b:4,5-b’]bis [1,4]benzothiazine (TRPZ). TRPZ is a heteroacene with a rigid, pi-conjugated structure, multiple reactive sites, and unique spectroscopic properties. Here we coupled TRPZ to a tert-butyl carbamate (BOC) protected 2,2-bis(hydroxymethyl)propanoic acid (bisMPA) dendron via azide-alkyne Huisgen cycloaddition. Deprotection of the protected amine groups on the dendron afforded a cationic terminated amphiphile, TRPZ-bisMPA. TRPZ-bisMPA was nanoprecipitated into water to obtain nanoparticles (NPs) with a hydrodynamic radius that was <150 nm. For comparison, TRPZ-PG was encapsulated in pluronic-F127 (Mw …

Electrochemical Characterization Of Surface-Immobilized Metal Nanostructures: Stability, Atomic Level Doping, Catalysis, And Sensing Applications., Badri Prasad Mainali

Electronic Theses and Dissertations

This dissertation has two main themes. The first theme involves voltammetric analysis of the stability of Au nanoparticles (NPs) under electrochemical and thermal treatment as a function of size, ligand stabilizer, and atomic composition. The second theme involves the use of Au NPs, electrophoretic deposition (EPD), and anodic stripping voltammetry (ASV) for electrochemical detection of analytes. The electrochemical size stability of 4.1, 15.1, and 50.3 nm average diameter Au NPs upon treatment with multiple electrochemical oxidation-reduction cycling in acidic electrolyte is monitored by observing changes in the peak oxidation potential (E_p) in ASV and the electrochemically measured surface …

Two Dimensional Nanoparticles/Nanozymes For Biosensing Augmented By Machine Learning, Nidhi Chintan Nandu

Legacy Theses & Dissertations (2009 - 2024)

Biosensing is an ever-evolving field with many resources devoted towards new approaches in sensing and refining the existing methods. For a long time, such approaches involved use of state-of-the-art instruments and were often proved to be time consuming and expensive. Nanoparticles with their unique properties, inexpensive synthesis and ease of manipulation have found purpose in myriad fields including biosensing. Different nanoparticles based on their composition, morphology, dimensionality, and surface modifications have already gained foot hold in the biosensor ranks. The unique opto-electric properties due to the quantum effect in the nanoparticles have also made them one of the leading alternatives …

Genotoxicity And Inflammatory Potential Of Stainless Steel Welding Fume Particles: An In Vitro Study On Standard Vs Cr(Vi)-Reduced Flux-Cored Wires And The Role Of Released Metals., Sarah Mccarrick, Valentin Romanovski, Zheng Wei, Elin M Westin, Kjell-Arne Persson, Klara Trydell, Richard Wagner, Inger Odnevall, Yolanda S Hedberg, Hanna L Karlsson

Chemistry Publications

Welders are daily exposed to various levels of welding fumes containing several metals. This exposure can lead to an increased risk for different health effects which serves as a driving force to develop new methods that generate less toxic fumes. The aim of this study was to explore the role of released metals for welding particle-induced toxicity and to test the hypothesis that a reduction of Cr(VI) in welding fumes results in less toxicity by comparing the welding fume particles of optimized Cr(VI)-reduced flux-cored wires (FCWs) to standard FCWs. The welding particles were thoroughly characterized, and toxicity (cell viability, DNA …

Characterization Of Ph – Responsive Nanocage Based On The Ferritin Iron Storage Protein, Satyam Singh

Theses and Dissertations

The iron-storage protein ferritin (Ftn) assembles into a protein cage structure with 24 subunits and octahedral (4-fold, 3-fold, 2-fold) symmetry. Each monomeric subunit contains a robust four-helix bundle fold. The fully assembled Ftn structure has a high degree of thermal stability (up to 100°C), a mono dispersed size (12 nm in diameter), and a large central cavity (7-8 nm in diameter). The central cavity stores ferric iron in phylogenetically diverse group of organisms, including humans. The central cavity has been used for encapsulation of cargoes such as other metals, contrast agents for imaging, small molecule drugs for therapy, …

Development Of Biomaterials For Drug Delivery, Raquel De Castro

Graduate Theses and Dissertations

Drug delivery systems (DDS) have highly evolved in the last decades with the development of hydrogels and nanoparticles. However, high systemic uptake, side effects, low bioavailability, and encapsulation efficiency continue to be a major hurdle faced by such DDSs.

Nanoparticles and hydrogels can be specifically designed for targeted DDSs to mitigate some of the problems. This dissertation aimed to design two DDSs for ocular drug delivery and one for cancer treatment. The first project sought to develop chitosan nanoparticles (Cs-NP) using PEGDA as a copolymer to encapsulate gentamicin (GtS) for ocular drug delivery. Cs-NPs contain positive charges that can interact …

Polymers In Drug Delivery Systems, Aashay Paresh Pratap

Legacy Theses & Dissertations (2009 - 2024)

Conventional drug delivery is associated with challenges such as low bioavailability, reduced half-life, nonspecific interactions, high immunogenicity, and degradation of drug before reaching the target. Modern drug delivery systems are designed to overcome the challenges of conventional drug delivery methods. Polymers play a crucial role in the development of modern drug delivery systems. Polymers form delivery vehicles that improve the therapeutic efficacy and reduce the side effects of a drug. Furthermore, it is possible to control the release of drug by using the delivery vehicles. Polymeric vehicles exist in different forms such as polymeric nanoparticles, hydrogels, and vesicles. Each form …

Electrochemical Oxidation Of Individual Silver Nanoparticles: Exploring The Effect Of Particle Shape, Capping Ligand, Electrolyte, And Potential On The Signal, Jazlynn Sikes

Graduate Theses and Dissertations

Nanomaterials have revolutionized science and technology. Their unique properties can be exploited, and nanoparticles are being used as catalysts, antimicrobials, drug delivery vehicles, sensors, and more. However, the fundamental properties of nanomaterials and their interactions with their surrounding environments are still poorly understood. In this work, a single-particle approach was used to observe the effects of capping ligand, surrounding solution, and particle shape on the oxidative process to gain deeper understanding of silver nanoparticle properties. When allowed the opportunity, the particles will adsorb to the electrode surface then oxidize in rapid succession upon electrode activation, regardless of capping ligand as …

Fabrication Of Metal-Silicon Nanostructures By Reactive Laser Ablation In Liquid, Eric J. Broadhead

Theses and Dissertations

Metal-silicon nanostructures are a growing area of research due to their applications in multiple fields such as biosensing and catalysis. In addition, silicon can provide strong support effects to metal nanoparticles while being more cost effective than traditionally used supports, like titania. Traditional wet-chemical methods are capable of synthesizing metal-silicon nanostructures with a variety of composition and nanoparticle shapes, but they often require high temperatures, toxic solvents, strong reducing agents, or need capping agents added to stabilize the nanoparticles. Laser processing is an emerging technique capable of synthesizing metal-silicon composite surfaces that offers a faster, simpler, and greener synthesis route …

Detection Of 2,4,6-Trinitrotoluene Using A Colorimetric Gold Nanoparticle Air Cassette Filter, Andrea I. Ferrer Vega

Theses and Dissertations

Trinitrotoluene (TNT) is an explosive commonly used during military and terrorist activities. Current methods to identify this compound require sampling, transport and analysis at a forensic lab using analytical instrumentation. However, on-site detection is needed to assist efforts to prevent detonation. Gold nanoparticles have been used as sensors throughout the years due to their versatility and surface enhanced Raman scattering properties in the presence of an analyte and low limits of detection. By taking advantage of the Meisenheimer complex that TNT forms in the presence of amines, it is possible to determine its presence at picogram levels. Subsequently, adhering amine …

Detection Of 2,4,6-Trinitrotoluene Using A Colorimetric Gold Nanoparticle Air Cassette Filter, Andrea I. Ferrer Vega

Master of Science in Forensic Science Directed Research Projects

Trinitrotoluene (TNT) is an explosive commonly used during military and terrorist activities. Current methods to identify this compound require sampling, transport and analysis at a forensic lab using analytical instrumentation. However, on-site detection is needed to assist efforts to prevent detonation. Gold nanoparticles have been used as sensors throughout the years due to their versatility and surface enhanced Raman scattering properties in the presence of an analyte and low limits of detection. By taking advantage of the Meisenheimer complex that TNT forms in the presence of amines, it is possible to determine its presence at picogram levels. Subsequently, adhering amine …

New Weldable 316l Stainless Flux-Cored Wires With Reduced Cr(Vi) Fume Emissions Part 1 – Health Aspects Of Particle Composition And Release Of Metals, Yolanda Hedberg

Chemistry Publications

Welding fumes have been found to be carcinogenic and stainless steel welders may be at higher risk due to increased formation of hexavalent chromium (Cr(VI)). The slag-shielded methods, identified to generate most airborne particles and Cr(VI), would potentially be most harmful. With ever-stricter limits set to protect workers, measures to minimize human exposure become crucial. Austenitic stainless steel flux-cored wires of 316L type have been developed with the aim to reduce the toxicity of the welding fume without compromised usability. Collected particles were compared with fumes formed using solid, metal-cored and standard flux-cored wires. The size, morphology and composition were …

One-Pot Synthesis Of Graphene Hydrogel-Anchored Cobalt-Copper Nanoparticles And Their Catalysis In Hydrogen Generation From Ammonia Borane, Ibtihel Zaier, Önder Meti̇n

Turkish Journal of Chemistry

We reported a facile one-pot synthesis of bimetallic CoCu nanoparticles (NPs) anchored on graphene hydrogel (GH-CoCu) as catalysts in hydrogen generation from the hydrolysis of ammonia borane (HAB). The presented novel one-pot method composed of the reduction of the mixture of graphene oxide, cobalt(II), and copper(II) acetate tetrahydrates by aqueous ethylene glycol solution in a teflon-coated stainless-steel reactor at 180 °C. The structure of the yielded GH-CoCu nanocatalysts was characterized by TEM, SEM, XRD, XPS, and ICP-MS. This is the first example of both the synthesis of bimetallic CoCu NPs anchored on GH and the testing of a hydrothermally prepared …

Synthesis Of Ni/Al2o3 Catalysts Via Alkaline Polyol Method And Hydrazine Reduction Method For The Partial Oxidation Of Methane, Ezgi̇ Bayrakdar Ateş, Tuba Gürkaynak Altinçeki̇ç, Mehmet Ali̇ Faruk Öksüzömer

Turkish Journal of Chemistry

Nickel catalysts supported on γ-Al2O3 were synthesized in the presence of polyvinylpyrrolidone (PVP) using both alkaline polyol method and hydrazine reduction method while fixing the weight ratio of [(PVP)]/[Ni(CH3COO)2·4H2O] at 2. The effects of hydrazine [N2H5 OH]/[Ni] and [NaOH]/[Ni] molar ratios on the structural properties of the catalysts were characterized by transmission electron microscopy (HRTEM) and by X-ray diffraction (XRD). The average of monodispersed Ni nanoparticles ranged between 8.0 and 13.0 nm. The catalytic tests were performed for the partial oxidation of methane in the temperature range of 600-800 °C under a flow rate of 157,500 L kg-1 hr-1 with …

Study On Potential Applications And Toxicity Analysis Of Green Synthesized Nanoparticles, Rajni Garg, Priya Rani, Rishav Garg, Nnabuk Okon Eddy

Turkish Journal of Chemistry

Nanomaterials have garnered the significant interest of scientists owing to their technological as well as medical applications. In particular, metal and metal oxide nanoparticles have gained prominence because of their enhanced performance as compared to their bulk counterparts. Metal-supported nanomaterials are anticipated to make major contributions to solving today's most challenging issues, like energy harvesting and environmental remediation. The incorporation of nanoparticles into sensors has significantly enhanced their precision and selectivity. With the advent of green chemistry, green synthetic techniques have been prioritized for the synthesis of single and multicomponent nanomaterials. In the current review, we have addressed the multidimensional …

Design, Synthesis And Applications Of Nanoparticles In Suppression Of Mosquito-Born Flaviviridae Viruses, Maria R. Blahove

Electronic Theses and Dissertations

Recently, nanoparticles have become an origin of exploration in the chemistry field due to their unique medical uses. The current drug delivery models of nanoparticles often include a metal base with a drug conjugated to its surface. However this raises concerns regarding toxicity. A novel approach to solving this dilemma is the development of nanosized biocompatible polymer-based micelles, created from PEG-PCL-PEG triblock polymer, and formed around a drug of choice. The goal is to create a drug carrier nanoparticle system that is labile at a specific intracellular pH, without undue toxicity to the cell. This creates a drug-loaded nanoparticle that …