Physical Sciences and Mathematics Commons^™

Halide Substitution Of Ternary Bismuth Chalcogenides For Photovoltaic Applications, Thomas Boggess

Theses and Dissertations

Semiconductors play an integral part in modern society. From computing to LEDs their use is ubiquitous, and no field is more reliant on them than that of power generation. Current political movements have seen a push to decrease reliance on traditional forms of power generation, which relies on fossil fuels, to renewable sources such as solar power. However, current commercial solar panels, based on silicon, are lacking in efficiency, only reaching between 18% and 22% efficiency.¹ In recent years, materials called perovskites have been garnering significant attention as possible replacements for silicon cells due to their favorable optoelectronic properties. …

Synthesis And Topochemical Manipulation Of New Layered Perovskites, Lea Gustin

University of New Orleans Theses and Dissertations

Metastable layered perovskites containing interlayer transition metals can readily be obtained by simple ion exchange reactions on receptive hosts, such as those of the Dion-Jacobson and Ruddlesden-Popper structure types. In this work, we focused on adding to the library of layered perovskites by not only creating new compounds, but by also showing their ability to be further manipulated, and by studying the stability of the series through thermal behavior studies.

The reactions with transition metal halides are particularly interesting since they often lead to novel architectures and magnetic behavior. On subsequent heat treatment, these exchange products typically decompose to thermodynamically …

New Dion-Jacobson And Ruddlesden- Popper Layered Perovskites Prepared By Topochemical Methods, Dariush Montasserasadi

University of New Orleans Theses and Dissertations

Layered perovskites can be classified in three major groups: Dion-Jacobson AA′_n-1B_nO_3n+1, Ruddlesden-Popper A₂A′_n-1B_nO_3n+1,and Aurivillius phase (Bi₂O₂)A′_n-1B_nO_3n+1. (A: Alkali metal, Alkali-earth metal; A′: Lanthanides and Bi; B: Ti, Nb, Ta; n: thickness of slabs). For more than two decades researchers have shown much interest in this series because of their magnetic and electrical properties. Tuning synthesis parameters such as temperature, time, and host structure can be used to direct such properties. Low temperature synthetic methods (topochemical methods) allow …

Development Of Monolithic Stationary Phases For Cation-Exchange Capillary Liquid Chromatography Of Peptides And Proteins, Xin Chen

Theses and Dissertations

This dissertation focuses on the preparation of polymeric monolithic capillaries for ion exchange chromatography of peptides and proteins, since polymeric monoliths have shown promise for providing improved protein separations. Characteristics of monolithic columns include low back pressure, simplicity of fabrication and biocompatibility. Preparation of strong and weak cation-exchange monolithic stationary phases in 75 μm I.D. capillaries by direct in situ copolymerization was achieved using various functional monomers including sulfopropyl methacrylate, phosphoric acid 2-hydroxyethyl methacrylate, bis[2-(methacryloyloxy)ethyl] phosphate and 2-carboxyethyl acrylate with polyethylene glycol diacrylate and other PEG materials. The resulting monoliths provided excellent ion exchange capillary LC of peptides and proteins …

Exploratory Synthesis Of New Open-Framework Iron (Ii,Iii)-Containing Polyanion Systems Targeted For Lithium-Ion Battery Applications, Gregory Becht

All Dissertations

The chemistry demonstrated in this dissertation is concerned with the synthesis, structure, properties and applications of inorganic solids containing iron(II,II) redox centers. The endeavor in exploratory synthesis is due largely to the employment of molten salt fluxes such as alkali metal chloride. These halide-fluxes act in two parts; 1) as a solvent to lower the reaction temperature and 2) as an in situ source of unavailable alkali oxides through metathesis reactions. Using these halide fluxes has allowed for the discovery of several new transition metal-containing phosphates, arsenates, and vanadates for a structure/property correlation study. From this study the selected compounds …

Ion-Association Complexes Of Thallium And Mercury With Rhodamine 6g In Aqueous Solution, Nasrein El-Masri

University of the Pacific Theses and Dissertations

The present study involves the determination of traces of thallium and mercury in aqueous solution by forming ion-association complexes of these metals with rhodamine 6G (R6G) in the presence of iodide. Thallium(lll) and mercury(Il) are able to quench the fluorescence of R6G in the presence of iodide by forming ion—association complexes, and the degree of quenching correlates with the thallium(III) or mercury(II) concentrations . By using this method, the minimum amount of thallium- (III) that can be determined in aqueous solutions is approximately 4.00 X 10-6m, while the minimum amount of mercury(II) is approximately 3.00 X 10-6m. Thallium(I) cannot be …

The Dependence Of The Apparent Pk Of Ion Exchange Celluloses Of Ionic Strength, Paul Cyril Gillespie

Theses and Dissertations

Diethylaminoethyl cellulose was titrated with acid and base in various concentrations of NaCl. The pK values were determined from titration curves using a graphical technique. Two titratable groups were observed from the acid titration curve, a major and a minor group. The minor group, which represented 20% of the acid titration, was barely detectable in the base titration curve and had a salt-independent pK of 6.0. The pK of the major group was strongly salt-dependent and was approximately a linear function of log N NaCl. An equilibrium shift caused by the counter ion may explain the salt dependence. Hydrogen bonding …

An Investigation Of Solvent Extraction Techniques In The Determination Of Formation Constants Of Complex Species In Aqueous Silver Chloride Solution, David Martin Bodily

Theses and Dissertations

Solvent extraction techniques have been used to determine formation constants for molecular silver chloride and dichloro silver (I) ion in unsaturated aqueous solutions. Nitrobenzene was used to extract the molecular silver chloride from the aqueous silver chloride solution. The total concentration of silver in each phase was determined by radioassay techniques and related by an expression involving the equilibrium constants. The reciprocal of the distribution ratio times the activity of the chloride ion was plotted versus the activity of the chloride ion and portions of the curve were analyzed by the method of least squares to obtain values for the …

An Investigation Of The Formation Constant Of Molecular Silver Chloride Using Ion Exchange Techniques.|Nii.|Pan Investigation Of The Rate Of Precipitation Of Silver Sulfide By Thioacetamide, James W. Pyper

Theses and Dissertations

The first part of this work reports on the investigation of the formation constant of molecular silver chloride using ion exchange techniques. In order to determine the formation constant, it was necessary to develop a method of rinsing the sorbed molecular silver chloride from the resin. It was found that desorption with nitrobenzene would remove the sorbed molecular species. However, the formation constant was not calculated since the nitrobenzene used contained hydrogen ion and chloride ion which removed silver ion as well as the molecular species. In the study of the formation of silver sulfide by the reaction between the …

An Investigation Of Complex Species In Silver Chloride Solutions I. Solubility Measurements ; Ii. Ion Exchange Methods, Harry G. Hecht

Theses and Dissertations

The complex species in silver chloride solutions have been investigated by solubility measurements and by ion exchange methods in this work. The solubility of silver chloride in solutions of varying chloride ion concentrations was determined by radioassay techniques. The method of least squares was used to evaluate the constants for the formation of the aqueous silver chloride and the dichloro-complex species; the values being 1.99 x 103 and 2.98 x 104, respectively, at 25.00°C. Aqueous solver chloride has been shown to be sorbed by Amberlite IR-120 from silver chloride solutions which have an ionic strength of 0.2. This sorption has …

Reactions Of Carbonyl Compounds With Amberlite Ir-45, Nathaniel Joseph Lane Jr.

University of the Pacific Theses and Dissertations

It is the purpose of this thesis to explore the experimental relationships which exist between Amberlite IR-45 and various carbonyl compounds with the hope that the knowledge obtained may ultimately form the basis of a new separation technique.

The Effect Of Cross-Linkage On Internal Diffusion In Dowex-50 Ion Exchange Resin, John Paul Peterson Jr.

University of the Pacific Theses and Dissertations

As far back as the time of Aristotle sand filters were used to purify water. However it was not until the time of Thompson and Way (1848), two English agricultural chemists, that the idea of actual exchange of ions was proposed. Ion exchange has been investigated extensively, resulting in applications to softening of water, purification of sugar, separation of compounds, recovery of metals, many pharmaceutical separations and many others.

It has been proposed that the internal diffusion should be related to the internal structure of the ion exchange resin. The object of this research was to measure the internal diffusion …