Chemistry Commons^™

Organic-Inorganic Hybrid Materials For Piezoelectric/Triboelectric Nanogenerator, Aminur Rashid Chowdhury

Theses and Dissertations

Nanogenerator has been a major focus among researchers of recent time due to its versatile use in everyday life. Though the discovery of the piezoelectricity and the triboelectricity dates back to 19th century, the use of these phenomena has not been in practical use till 2006. In this study we demonstrate the practical application of piezoelectric and triboelectric nanogenerator comprised of different copolymer and piezoelectric ceramic. The largely known piezoelectric polymer Polyvinylidene fluoride (PVDF) has also been utilized. The enhancement of piezoelectric properties of PVDF has been achieved by utilizing surface activation of accommodating ceramic. The Li doped ZnO has …

Growth Factors In The Human Body: A Conceptual Update, Estefania Alexandre, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Growth factors are found in most of the organisms including insects, humans, plants, etc. The name ‘growth factors’ became known when the substances were active in stimulating the growth of cells and tissues. Growth factors are regulatory species (signaling molecules mainly proteins) that are generated by the body which function in binding to receptors on the cell surface and are required to stimulate the growth in living responsive cells by triggering cellular proliferation and/or cellular differentiation pathways, as well as by regulating gene transcription in the nucleus. They are quite versatile by promoting cell growth and act in a paracrine, …

Studies On Regulation Of Dihydrotestosterone Binding To And Releasing From The Androgen Receptor, Tahyra M. Resto Santos

Theses and Dissertations

The androgen receptor (AR) is a nuclear receptor that responds to testosterone and 5α-dihydrotestosterone (DHT) by modulating gene expression in a variety of cells, including prostate and muscle tissues. Studies of small molecule interaction with AR have shown diphenyl compounds inhibiting through a binding site labeled Binding Function 3 (BF3). The goal of this research is to analyze the interaction of the BF3 site with DDT and related compounds. Amino acids that are exposed on the surface of the BF3 that might interact with different compounds were mutated. Mutant proteins were tested experimentally for their impact on the inhibition the …

The Development Of Screening Platforms To Identify Novel Anti-Infectives That Inhibit Protein Synthesis In Pseudomonas Aeruginosa, Casey Anne Hughes

Theses and Dissertations

Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, is a leading cause of nosocomial infections and is becoming increasingly antibiotic resistant. Aminoacyl-tRNA synthetases (aaRSs) catalyze the covalent attachment of amino acids to their cognate tRNAs and serve as validated targets for the development of new anti-infectives. In P. aeruginosa, the genome contains two genes (tyrS and tyrZ) which encode two distinct TyrRS enzymes. The genes encoding both P. aeruginosa TyrRS-Z and TyrRS-S were cloned, overexpressed in E. coli cells, and purified to homogeneity. Both forms of TyrRS were active in aminoacylation and were developed into screening platforms using scintillation proximity …

Molten-Salt Synthesized Pyrochlore Nanoparticles For Multifunctional Applications, Jose P. Zuniga

Theses and Dissertations

There is a need in the scientific world to design and develop high quality nanomaterials with multifunctional applications. In this work, we explore the molten-salt method (MSS) as a new green method for the synthesis of complex metal oxides. We adjusted all synthesis parameters such as time, temperature and pH to generate an optimum La2Hf2O7 nanoparticle with a well define shape and surface. Activator ions such as Eu3+, Tb3+, Dy3+, Bi3+ and uranium ion (U4+, U6+) were used to monitor its structural and optical behavior effect when doped.

Our results showed effective quantum yield, thermal, pressure stability, near to white …

Roles Of Oxygen Vacancies And Ph Induced Size Changes On Photo- And Radioluminescence Of Undoped And Eu3+-Doped La2zr2o7 Nanoparticles, Santosh K. Gupta, Maya Abdou, Jose P. Zuniga, Partha Sarathi Ghosh, Enrique Molina, Ben Xu, Mircea Chipara, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Defect, doping and particle size play important roles on the optical performance of nanophosphors. In this study, undoped La2Zr2O7 NPs (LZO) displayed multicolor emission under UV irradiation due to the presence of ionized oxygen vacancies in the band gap. In addition, we explored the effect of particle size of La2Zr2O7:Eu3+ (LZOE) NPs on their structure, surface area, photoluminescence, radioluminescence, lifetime and quantum yield. There is progressive decrease in luminescence output and quantum yield as the coprecipitation pH is raised to prepare the single-source precursors for the molten salt synthesis of the NPs. Under X-ray irradiation, the LZOE …

Palladium-Catalyzed Direct Α‑C(Sp3) Heteroarylation Of Ketones Under Microwave Irradiation, Andrew Quillen, Quynh Nguyen, Matthew Neiser, Kara Lindsay, Alexander Rosen, Stephen Ramirez, Stefana Costan, Oscar Rodriguez, Diego Rivera, Abdurrahman Atesin, Tülay A. Ateşin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Heteroaryl compounds are valuable building blocks in medicinal chemistry and chemical industry. A palladium-catalyzed direct α-C(sp3) heteroarylation of ketones under microwave irradiation is developed and reported in this study. Under optimized conditions, twenty-eight (28) heteroarylated ketones were prepared in this study to demonstrate the substrate scope of this reaction. The ground-state optimized structure of Pd(0) active catalyst with 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (XPhos) in toluene, and the products of its reaction with 3-bromopyridine and acetophenone were studied using all-atom density functional theory. This study provided insightful information for palladium catalytic system design to generate heteroaryl compounds.

Phytochemical Investigation Of Magnolia Grandiflora Green Seed Cones: Analytical And Phytoceutical Studies, Bo Garza, Alondra Echeverria, Felipe Gonzalez, Orlando Castillo, Thomas Eubanks, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Phytochemicals are inevitable part of human civilization. It is impossible to say exactly when menfolk started to take plant portions to cure various diseases. Phytochemical investigation of diethyl ether and ethanol extracts of Magnolia grandiflora green seed cones has been carried out. Extraction, isolation, and identification of the phytochemicals were carried out. Structures were determined by various analytical methods including extensive nuclear magnetic resonance, gas chromatography‐ mass spectroscopy, and X‐ray crystallographic analyses. Structures of the three compounds viz. 5,5′‐diallyl‐[1,1′‐biphenyl]‐2,2′‐diol (I), 3′,5‐diallyl‐[1,1′‐biphenyl]‐2,4′‐ diol (II), and (3S,3aS,8S,9aS,10aR,10bS,E)‐8‐hydroxy‐3,6,9a‐trimethyl‐3a,4,5,8,9,9a, 10a,10b‐octahydrooxireno[2′,3′:9,10]cyclodeca[1,2‐b]furan‐2(3H)‐one (III) were confirmed by X‐ray crystallographic analysis. GS‐MS studies of the isolated oil, eluted …

Α-Actinin Anchors Psd-95 At Postsynaptic Sites, Lucas Matt, Karam Kim, Anne E. Hergarden, Tommaso Patriarchi, Zulfiqar A. Malik, Deborah K. Park, Dhrubajyoti Chowdhury, Olivia R. Buonarati, Peter B. Henderson, Yonghong Zhang

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Despite the central role PSD-95 plays in anchoring postsynaptic AMPARs, how PSD-95 itself is tethered to postsynaptic sites is not well understood. Here we show that the F-actin binding protein α-actinin binds to the very N-terminus of PSD-95. Knock-down (kd) of α-actinin phenocopies kd of PSD-95. Mutating lysine at position 10 or lysine at position 11 of PSD-95 to glutamate, or glutamate at position 53 or glutamate and aspartate at positions 213 and 217 of α-actinin, respectively, to lysine impairs in parallel PSD-95 binding to α-actinin and postsynaptic localization of PSD-95 and AMPARs. These experiments identify α-actinin as a critical …

Pharmacological Aspects Of Resveratrol, Raisa Ramirez, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Resveratrol [(E)-5-(4-hydroxystyryl) benzene-1,3-diol], also known as 3,4′,5-trihydroxystilbene also known as resveratrol is classified as a phytoalexin in plants such as nuts, cocoa, berries and grapes for self-defense against injury and pathogenic attacks by bacteria and fungi. Research on this compound did not gain popularity until the 1990s when a published paper implied the relationship between resveratrol and the decrease in cardiovascular complications due to the consumption of grape fermented wine in French populations. This observation sparked research on resveratrol even though its concentration in wine is relatively low, leading to the realization that resveratrol has potential for benefits in other …

Thermally Induced Disorder-Order Phase Transition Of Gd 2 Hf 2 O 7 :Eu 3+ Nanoparticles And Its Implication On Photo-And Radioluminescence, Santosh K. Gupta, Maya Abdou, Partha Sarathi Ghosh, Jose P. Zuniga, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Crystal structure has a strong influence on the luminescence properties of lanthanide-doped materials. In this work, we have investigated the thermally induced structural transition in Gd 2 Hf 2 O 7 (GHO) using Eu 3+ ions as the spectroscopic probe. It was found that complete phase transition from the disordered fluorite phase (DFP) to the ordered pyrochlore phase (OPP) can be achieved in GHO with the increase of annealing temperature from 650 ? 1100 ? 1300 °C. OPP is the more stable structural form for the GHOE nanoparticles (NPs) annealed at a higher temperature based on the energy calculation by …

Photocatalytic Degradation Of Simazine Using Zno/Go Composites, Kenneth Ray Flores

Theses and Dissertations

The photocatalytic degradation of simazine (SIM) by Zinc oxide/graphene oxide (ZnO/GO) composites, under visible light irradiation, was investigated to determine various reaction parameters, of initial pH, ZnO loading on GO, and catalyst mass. A pH of 2 was determined to be the optimal reaction pH for all ZnO/GO catalysts. A loading mass of 40mg for the 20 & 30mmol composites; whereas a 10mg mass was determined to be most effective for the 10mmol composite. The reaction followed second order kinetics for the degradation process, the reaction dependence was determined to be on the concentration of SIM in solution. All ZnO/GO …

Green Synthesis/Biosynthesis Of Silver Nanoparticles By Using Orange Peel Extract, Leela Joshi

Theses and Dissertations

Joshi, Leela, Green Synthesis/Biosynthesis of Silver Nanoparticles by Using Orange Peel Extract. Master of Science (MS), December, 2018, 40 pages, 23 figures, references, 36 titles. In this work, we report synthesis of silver nanoparticles (AgNPs) with an average size of ~6 nm. The aqueous solution of Ag+ ions is reduced using an aqueous extract from orange peel (Citrus Sinensis) at varying pHs. Reduction of Ag+ ions in solution was monitored using UV-visible absorption spectroscopy, and the corresponding surface plasmon resonance of AgNPs at 435 nm. The solution changed color from yellow to reddish-brown upon bioreduction of silver nitrate in orange …

Three Dimensional Carbon Nanotube Yarn Based Perovskite Solar Cells, Istiak Hussain

Theses and Dissertations

Perovskite solar cells (PSC) have emerged as a promising photovoltaic technology in lab scale with a short time of research due to their high power conversion efficiency, simple device fabrication, all solid-state structure and the possibility to ingrate the traditional device into fiber format. In this work, a three-dimensional (3D) perovskite solar cell is demonstrated using functionalized carbon nanotube yarn (CNT) as both cathode and anode. TiO2 and 2,2,7,-7-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD) are used as the electron transporting and hole transporting material respectively. The TiO2 oxide layer is deposited on the top of the twisted carbon nanotube yarn and annealed with TiCl4 …

Effects On Altering Reaction Conditions In Suzuki Cross Coupling Reactions Using The Microwave, Javier Alejandro Perez

Theses and Dissertations

Over the last few decades, Suzuki coupling has become a common process for the synthesis of intermediates in pharmaceutical and industrial applications. It is well known that palladium is an effective catalyst for the formation of cross-coupled products. Therefore, this catalyst was tested in a series of reactions. Also, it is believed that other catalyst with similar properties to palladium can work, for example cerium. Therefore, a cerium hydroxide catalyst was synthesized in lab and used as a potential catalyst for the Suzuki reaction. For this study, some bases were investigated (NaOH, Na2CO 3, K3PO4, NaNO3, NaHCO3, etc) for the …

Functional Materials, Device Architecture, And Flexibility Of Perovskite Solar Cell, Istiak Hussain, Hoang Phong Tran, Jared R. Jaksik, Justin Moore, Mohammed Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Perovskite solar cells (PSCs) are an emerging photovoltaic technology that promises to offer facile and efficient solar power generation to meet future energy needs. PSCs have received considerable attention in recent years, have attained power conversion efficiencies (PCEs) over 22%, and are a promising candidate to potentially replace the current photovoltaic technology. The emergence of PSCs has revolutionized photovoltaic research and development because of their high efficiencies, inherent flexibility, the diversity of materials/synthetic methods that can be employed to manufacture them, and the various possible device architectures. Further optimization of material compositions and device architectures will help further improve efficiency …

Molten-Salt Synthesis Of Complex Metal Oxide Nanoparticles, Jose P. Zuniga, Maya Abdou, Santosh K. Gupta, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we …

Vitamin D: Controversy Cancer And Beyond, Cristian J. Rosales, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Vitamins are an essential part to wellbeing. This was not something always known however, as the Germ theory was the accepted thesis of the 18th century. It was found that certain accessory factors helped mitigate and even cure these diseases such as beriberi, scurvy, and rickets. Accessory factors, later coined vitamins by Casimir Funk, are an essential constituent of the human diet. Vitamin D is technically not a vitamin but functions as a steroid hormone whose most well-known purpose is calcification of the human skeleton. This helps prevent osteomalacia in adults and rickets, a serious problem in children due to …

Advanced Cotton Fibers Exhibit Efficient Photocatalytic Self-Cleaning And Antimicrobial Activity, Jared Jaksik, Phong Tran, Veronica Galvez, Isaac Martinez, Darian Ortiz, Andy Ly, Monica Mcentee, Erin M. Durke, Sayeeda Tj Aishee, Margaret Cua, Ahmed Touhami, H. Justin Moore, M. Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Functional cotton fibers have a wide range of applications in domestic, commercial, and military settings, and so enhancing the properties of these materials can yield substantial benefits. Herein, we report the creation of functional fibers that are self-cleaning, anti-microbial, and protective against UV radiation. A uniform, and high surface area films of TiO2 were deposited on cotton fibers and gold/silver nanoparticles were directly incorporated on the nanostructured TiO2 surface. The synthetic method is simple and the produced TiO2 film is homogenous and the nanoparticles were shown to be effectively distributed on the surface using a simple photocatalytic reduction method. …

Removal Of Cu2+ And Ni2+ From Aqueous Solution Using Sno2 Nanomaterial Effect Of: Ph, Time, Temperature, Interfering Cations, Abigail M. Zepeda, Daisy Gonzalez, Luis Gonzalez Heredia, Karina Marquez, Cesar Perez, Erika Pena, K. Flores, Carolina Valdes, Thomas Eubanks, Jason Parsons, J. Cantu

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Tin oxide, SnO2, nanomaterial was synthesized and tested for the removal of Cu2+ and Ni2+ ions from aqueous solutions. Various parameters for the binding were investigated in batch studied, which included pH, time, temperature, and interferences. In addition, isotherm studied were performed to determine the maximum binding capacity for both Cu2+ and Ni2+ ions. The optimal binding pH determined from the effects of pH were to be at pH 5 for both the Cu2+ and Ni2+ ions. The isotherm studies were performed at temperatures of 4°C, 25 °C, and 45 °C for both the Cu2+ and Ni2+ ions and were …

Three-Dimensional Carbon Nanotube Yarn Based Solid State Solar Cells With Multiple Sensitizers Exhibit High Energy Conversion Efficiency, Glenn Grissom, Jared Jaksik, Monica Mcentee, Erin M. Durke, Sayeeda Tj Aishee, Margaret Cua, Okenwa Okoli, Ahmed Touhami, H. Justin Moore, M. Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Fiber-type dye sensitized solar cells that are non-metallic, flexible, and thread-like in structure have many potential military and functional textile applications. With the use of quantum dots (QD), exciton transfer facilitators (Phenyl-C61-butyric acid methyl ester-PCBM) and Poly(3-hexylthiophene-2,5-diyl-P3HT), and careful preparation of the TiO2 oxide layer deposited on the carbon fiber working electrode, an optimized efficiency of 7.6% was obtained. Carbon nanotube yarn (CNTY) was used to prepare both the working and counter electrodes of the fabricated cells. TiCl4 annealing of the TiO2 layer was carried out and the resulting oxide layer morphology was found to be very uniform. The quantum …

Conformational Analysis Of A Taddol-Based Phosphoramidite P,N Ligand In A Palladium(Ii) Η3-Π-Allyl Complex, Tülay A. Ateşin, Abdurrahman Atesin, Oscar Rodriguez, Diego Rivera, Lohany Y. Garcia

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Highlights

• Two lowest energy conformers differ in allyl conformation, conformer with exo allyl having lower energy.

• Lowest energy conformer has “chair” conformation of 7-membered ring and “edge-on/face-on/face-on/edge-on” array of pH groups.

• Next lowest energy conformer with exo allyl has alternating “edge-on/face-on” arrangement and “twist” 7-membered ring.

• Changes in “chair/twist” conformations with different substrates is possible due to 2.4 kcal/mol energy difference.

• These results explain stereochemical outcome of the reaction, and will guide design of new catalysts.

Abstract

The most stable conformations of a TADDOL-based phosphoramidite P,N ligand coordinated to a palladium(II) η3-π-allyl fragment have been investigated using …

Functionalized And Nanostructured Fibers For Photocatalysis And Energy Conversion, Jared R. Jaksik

Theses and Dissertations

Fiber-type / flexible materials present a unique opportunity for the incorporation of photocatalytic / energy generating technology, as they typically have a broad surface area exposed to light (clothing, curtains, carpet). In this work, several methods of harvesting incident light striking a flexible substrate to perform useful work are examined. In the first section a gold and silver nanoparticle augmented TiO2 thin film textile coating is evaluated for its self-cleaning / UV-protective / anti-microbial properties, and stability of the film / substrate over time is examined. In the second section a dye sensitized / hybrid type solar cell architecture based …

Glutathione: A Small Molecule With Big Sense, Cristina E. Raya, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Glutathione, a peptide found in microbes, plants and animals including human plays a key role in maintaining healthy cells. The peptide exists in both reduced and oxidized forms. Synthesis of GSH occurs in the cytosol of cells, and the extent of glutathione synthesis relies on various factors, such as amino acid availability, protein activity etc. Once synthesized, glutathione exists in both forms: oxidized (GSSG) and reduced (GSH). Oxidized glutathione characterized by its disulfide linkage. On the other hand, presence of a thiol group characterizes the reduced glutathione. This thiol makes the tripeptide an essential component of health; it makes glutathione …

Effect Of Molten Salt Synthesis Processing Duration On The Photo- And Radioluminescence Of Uv- Visible- And X-Ray-Excitable La 2 Hf 2 O 7 :Eu 3+ Nanoparticles, Jose P. Zuniga, Santosh K. Gupta, Maya Abdou, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Ln 3+ -ion-doped nanomaterials possess excellent properties because of their high color purity, longer excited state lifetime, narrow emission, and large Stokes shifts. In this work, we studied the correlation between the luminescence properties of La 2 Hf 2 O 7 :Eu 3+ pyrochlore nanoparticles (NPs) synthesized by a molten salt synthesis (MSS) method at a relatively low temperature and several MSS processing durations (from 1 to 12 h). We synthesized these NPs with different sizes just by changing the MSS processing time without subjecting to high temperature. Raman spectroscopy confirmed the stabilization of the ideal pyrochlore structure of the …

Thermodynamic And Kinetic Study Of The Removal Of Cu2+ And Pb2+ Ions From Aqueous Solution Using Fe7s8 Nanomaterial, Jesus Cantu, Diego F. Gonzalez, Yvette Cantu, Thomas Eubanks, Jason Parsons

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In the present study, pyrrhotite (Fe7S8) was investigated for the removal of Pb2+ and Cu2+ ions from aqueous solution. The Fe7S8 material was prepared through a solvothermal method and was characterized using XRD. The average particle size for the nanomaterial was determined to be 29.86 ± 0.87 nm using XRD analysis and Scherrer's equation. Batch studies were performed to investigate the effects of pH, time, temperature, interfering ions, and the binding capacity of Pb2+ and Cu2+ ions to the Fe7S8 nanomaterial. During the pH profile studies, the optimum pH for the binding of Pb2+ and Cu2+ was determined to be …

Microwave Popped Co(Ii)-Graphene Oxide Hybrid: Bifunctional Catalyst For Hydrogen Evolution Reaction And Hydrogen Storage, Lin Wei, Karen Lozano, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In an effort to develop a multifunctional catalyst for hydrogen generation and adsorption applications, a facile and cost-effective microwave popping method was used to synthesize popped graphene oxide (PGO) and Co-PGO hybrid. Both samples have been explored and compared as hydrogen storage materials and as electrocatalysts for hydrogen evolution reaction (HER) for the first time. The loading of Co(II) species on the surface of the PGO enhanced the hydrogen storage capability of PGO from 0.04wt% to 0.08wt% as measured at 293K and 800 mmHg. Co-PGO is also acting as a better electrocatalyst for HER compared to the PGO counterpart.

Experimental And Computational Studies Of Rotation And Proton Tunneling In Organic Molecules And Molecular Dimers, Agapito Serrato Iii

Theses and Dissertations

An introduction to the relations of classical and quantum mechanics are presented in brief. As is an overview of the instrumentation and quantum chemical analysis performed to characterize the molecules presented in in this thesis. The pure rotational spectrum of 3,3,3-trifluoro-2(trifluoromethyl)propanoic acid, perfluorobutyric acid–formic acid dimer, and tropolone–formic acid dimer were measured using high-resolution microwave spectroscopy. The spectra have been observed using a cavity-based Fourier-transform microwave (FTMW) spectrometer and/or a chirped-pulse FTMW.

Microwave-Assisted Ring-Opening Polymerization Of Poly(Ε-Caprolactone), Nancy Obregon

Theses and Dissertations

Poly(ϵ-caprolactone) (PCL) is a biodegradable polyester notorious by its promising properties and applications in the biomedical field. In this work, microwave-assisted ringopening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) was performed. Stannous octoate [Sn(Oct)2] was used as catalyst with and without an alcohol initiator. The different initiators tested were glycerol, diethylene glycol (DEG) and poly(ethylene) glycol (PEG). Aiming to establish reaction parameters, the influence of different reaction times, temperatures, and monomer:initiator:catalyst ratios were examined. It was observed that the reaction was obtained and high molecular weight PCL was achieved successfully without an initiator. However, mixed results were obtained using an initiator. Products …

Removal Of Chromium(Vi) And Chromium(Iii) Ions From Aqueous Solution Using Bio-Char Generated From Agricultural Waste Products, Diego Fernando Gonzalez

Theses and Dissertations

Heavy metals are one of the most persistent and prevalent contaminants in the aquatic environment. The removal of chromium from aqueous solution, especially in the hexavalent form is difficult. New technologies, techniques and/or new materials have been designed in order to effectively and efficiently remove chromium from the aqueous environment. The project focuses on the comparison of the effects of pH, time, temperature, binding capacity on bio-char’ generated from agricultural waste produces vs an amino modified derivative of the bio-char. Pineapple skins were dried, ground, sieved, and pyrolyzed to produce a bio-char material. The bio-char was analyzed using FTIR to …