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Environmental Chemistry Commons

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2016

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Articles 1 - 30 of 73

Full-Text Articles in Environmental Chemistry

Assessing The Impact Of A Constructed Wetland Biome On The Ecosystem Health Of Cedar Run, Thomas Vasilopoulos, Casey Lee Dec 2016

Assessing The Impact Of A Constructed Wetland Biome On The Ecosystem Health Of Cedar Run, Thomas Vasilopoulos, Casey Lee

Senior Honors Projects, 2010-2019

A wetlands ecosystem is defined as “an area saturated by surface or groundwater at a frequency or duration sufficient to support...a prevalence of vegetation typically adapted for life in saturated soil conditions” (Batzer and Sharitz, 2007). Wetlands serve as biofilters and thus have been used to treat sewage and wastewater, as well as to restore the health of polluted water systems. Solly Walker and Lorinda Palin, owners of a certified natural and biodynamic farm called Avalon Acres located in Broadway, Virginia, constructed a wetland two years ago, using the stream, Cedar Run, that flows through their property. Pollution from agricultural …


A Pes Study Of Factors Influencing Metal Partitioning In Aquatic Systems: “Design Of Experiment As, Cd, Co, Cr, Cu, Pb, Ni, And Zn”, Eid A. Alkhatib, John Rapaglia, Leon Theim Dec 2016

A Pes Study Of Factors Influencing Metal Partitioning In Aquatic Systems: “Design Of Experiment As, Cd, Co, Cr, Cu, Pb, Ni, And Zn”, Eid A. Alkhatib, John Rapaglia, Leon Theim

Chemistry & Physics Faculty Publications

Mobility and bioavailability of heavy metals are related to their partitioning amongst suspended sediment and water. A Particle Entrainment Simulator (PES) is used to simulate sediment resuspention in natural surface water systems. The simulations were carried out under various conditions of water/suspended solids conditions. Five factors, each at various levels, are tested collectively: the pH of water at two levels (4 and 8), shear stress on bottom sediment at three levels (0.1, 0.3, and 0.5 N/m2 ) salinity of water at two levels (0.01 and 14.0 ppt), organic matter in sediment at three levels (0.50, 1.93, and 3.80%) and temperature …


Environmental Emission Of Pharmaceuticals From Wastewater Treatment Plants In The Usa, Bikram Subedi, Bommanna G. Loganathan Dec 2016

Environmental Emission Of Pharmaceuticals From Wastewater Treatment Plants In The Usa, Bikram Subedi, Bommanna G. Loganathan

Faculty & Staff Research and Creative Activity

The residual drugs, drug bioconjugates, and their metabolites, mostly from human and veterinary usage, are routinely flushed down the drain, and enter wastewater treatment plants (WWTP). Increasing population, excessive use of allopathic medicine, continual introduction of novel drugs, and existing inefficient wastewater treatment processes result in the discharge of large volumes of pharmaceuticals and their metabolites from the WWTPs into the environment. The effluent from the WWTPs globally contaminate ~25% of rivers and the lakes. Pharmaceuticals in the environment, as contaminants of emerging concerns, behave as pseudo-persistent despite their relatively short environmental half-lives in the environment. Therefore, residual levels of …


Persistent Organic Chemicals In The Pacific Basin Countries: An Overview, Bommanna G. Loganathan Dec 2016

Persistent Organic Chemicals In The Pacific Basin Countries: An Overview, Bommanna G. Loganathan

Faculty & Staff Research and Creative Activity

The Pacific Basin is a unique geographical region representing tropical, temperate and polar zones. This region is home to 2/3 of world’s population and consists of rapidly growing economies (countries) and highly developed countries. The Pacific Basin countries have had a history of use of persistent organic chemicals (POCs) at varying proportions during the last five decades. Due to diverse climatic and socio-economic conditions, the environment and biota in different countries in this basin have varying degrees of environmental contamination and effects on wildlife and humans. In this chapter, the historical background of POCs including, discovery, production, use, regulations/restrictions imposed, …


Interactions In The Cpsrp Dependent Targeting Of Light Harvesting Chlorophyll Binding Protein To The Thylakoid Membrane, Rory Henderson Dec 2016

Interactions In The Cpsrp Dependent Targeting Of Light Harvesting Chlorophyll Binding Protein To The Thylakoid Membrane, Rory Henderson

Graduate Theses and Dissertations

Targeting of proteins is a critical component of cellular function. A universally conserved targeting system of the cytosol utilizes a signal recognition particle (SRP) to target many proteins contranslationally to the endoplasmic reticulum in eukaryotes or the inner membrane in prokaryotes. A homologous SRP system exists in the chloroplast that delivers light harvesting chlorophyll binding proteins (LHCP) to they thylakoid membrane. The chloroplast SRP (cpSRP) is a heterodimer composed of a novel 43 kDa subunit and a 54 kDa subunit homologous to a component of the SRP system, SRP54. Many details regarding the interactions between the proteins of the cpSRP …


Going Beyond The Analysis Of Common Contaminants: Target, Suspect, And Non-Target Analysis Of Complex Environmental Matrices By High-Resolution Mass Spectrometry, Anna Katarina Huba Nov 2016

Going Beyond The Analysis Of Common Contaminants: Target, Suspect, And Non-Target Analysis Of Complex Environmental Matrices By High-Resolution Mass Spectrometry, Anna Katarina Huba

FIU Electronic Theses and Dissertations

The advancements in the field of analytical chemistry, and especially mass spectrometry, have been redefining the field of contaminant detection. While more traditional analysis was sufficient to screen for a small number of well-known compounds, new techniques such as high-resolution mass spectrometry, have enabled a fairly comprehensive screening for previously unknown contaminants. This is enormously beneficial with respect to the analysis of water, air, or soil quality in a society that continuously introduces novel anthropogenic compounds into the environment. This dissertation, thus, focused on the analysis of the uncharacterized portion of compounds in two types of complex environmental matrices (i.e., …


Aggregation And Coagulation Of C60 Fullerene As Affected By Natural Organic Matter And Ionic Strength, Hamid Mashayekhi Nov 2016

Aggregation And Coagulation Of C60 Fullerene As Affected By Natural Organic Matter And Ionic Strength, Hamid Mashayekhi

Doctoral Dissertations

With widespread production and use of C60 fullerene nanoparticles, their release to the environment and natural waters is inevitable. The colloidal nature of C60 fullerene in the aquatic environment significantly influences its behavior in the environment including its transport, bioavailability and toxicity to different organisms. Natural organic matter (NOM) is a ubiquitous and reactive material in aquatic environments with significant structural heterogeneity. Therefore, the effect of NOM molecules on the colloidal behavior of fullerene particles needs to be studied. A major part of NOM consists of humic acids (HA). HAs have pronounced effects on the aggregation of C …


Mercury Sulfide Dissolution In Environmental Conditions: Thermodynamic And Kinetic Approaches, Ping Jiang Nov 2016

Mercury Sulfide Dissolution In Environmental Conditions: Thermodynamic And Kinetic Approaches, Ping Jiang

FIU Electronic Theses and Dissertations

Mercury (Hg) is a global contaminant of ecosystems and human health risk, with complicated biogeochemical processes. Mercury sulfide (HgS) dissolution has been suggested as a key process in Hg cycling, as it could potentially increase the pool of inorganic Hg (iHg) for the production of methylmercury (MeHg). Despite previous sporadic observations of enhanced HgS dissolution under certain conditions, much remains unclear on mechanisms of HgS dissolution. The objective of my research was to advance the mechanistic understanding of HgS dissolution, concerning re-adsorption of released Hg, effects of thiol-ligands, and Hg speciation.

Considering the lack of feasible techniques to differentiate dissolution …


Specific Phosphate Sorption Mechanisms Of Unaltered And Altered Biochar, Kathryn D. Szerlag Nov 2016

Specific Phosphate Sorption Mechanisms Of Unaltered And Altered Biochar, Kathryn D. Szerlag

Masters Theses

Biochar has been shown to act as an effective sorbent for many organic and inorganic contaminants (including phosphate) and can help to improve the quality of our fresh water resources by preventing eutrophication. Most of the high efficiency biochar phosphate-adsorbent feedstocks are modified with chemical pretreatment, phytoremediation or anaerobic digestion to accumulate desired elements. The main objectives of this project were to first engineer magnesium (Mg) and calcium (Ca) altered biochar by chemical pretreatment followed by pyrolysis at either 350 or 550°C and evaluate their phosphate adsorption rate and potential as compared to their unaltered counterparts. Determination of surface physiochemical …


Development Of Filter-Based Surface Enhanced Raman Spectroscopic Assays For Rapid Detection Of Chemical And Biological Contaminants In Water, Siyue Gao Nov 2016

Development Of Filter-Based Surface Enhanced Raman Spectroscopic Assays For Rapid Detection Of Chemical And Biological Contaminants In Water, Siyue Gao

Masters Theses

Surface enhanced Raman spectroscopy (SERS) has been widely applied for rapid and sensitive detection of various chemical and biological targets. Here, we incorporated a syringe filter system into the SERS method to detect pesticides, protein toxins and bacteria in water. For the detection of chemical and protein targets, silver nanoparticles (Ag NPs) were aggregated by sodium chloride (NaCl) to form nanoclusters that could be trapped in the pores of the filter membrane to from the SERS-active membrane. Then a coating of capture (e.g. aptamer) was integrated on the nanoparticle substrate if needed. Then samples were filtered through the membrane. After …


Determination Of The Optical Properties Of Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Felisha Imholt, Ryan Caylor Oct 2016

Determination Of The Optical Properties Of Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Felisha Imholt, Ryan Caylor

Matthew E. Wise

The enhanced greenhouse effect is currently considered to be our most important global environmental problem. While the magnitude of radiation absorbed by greenhouse gases is known to a high certainty, the absorption of radiation by atmospheric aerosol particles is not. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which secondary organic aerosol particles (SOA) absorb visible light. Early in the research period, the UV/Vis technique was optimized for three solvent systems (methanol, water and 0.1 M hydrochloric acid). Using …


Determination Of Total Peroxide Content In Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Ryan Caylor Oct 2016

Determination Of Total Peroxide Content In Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Ryan Caylor

Matthew E. Wise

Secondary organic aerosol particles (SOA) formed from the oxidation of monoterpenes can impact the Earth’s radiation balance, act as cloud condensation nuclei and negatively affect human health. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which SOA absorb visible light. The inclusion of Concordia University in the Secondary Organic Aerosol From Forest Emissions Experiment (SOAFFEE) laboratory campaign at PNNL necessitated a change in the proposed experiments. An iodometric-spectrophotometric (IS) technique was developed to quantify the total peroxide content in SOA. …


Green Chemistry: Progress And Barriers, Sarah A. Green Oct 2016

Green Chemistry: Progress And Barriers, Sarah A. Green

Michigan Tech Publications

Green chemistry can advance both the health of the environment and the primary objectives of the chemical enterprise: to understand the behavior of chemical substances and to use that knowledge to make useful substances. We expect chemical research and manufacturing to be done in a manner that preserves the health and safety of workers; green chemistry extends that expectation to encompass the health and safety of the planet. While green chemistry may currently be treated as an independent branch of research, it should, like safety, eventually become integral to all chemistry activities. While enormous progress has been made in shifting …


Characterization Of S-Swcnt/Pf-Pd Dispersions And Networks, Tamara N. El-Hayek Ms., Jeffrey Blackburn, Andrew Ferguson, Tammy Pheuphong Oct 2016

Characterization Of S-Swcnt/Pf-Pd Dispersions And Networks, Tamara N. El-Hayek Ms., Jeffrey Blackburn, Andrew Ferguson, Tammy Pheuphong

STAR Program Research Presentations

Single-Walled Carbon Nanotubes (SWCNTs) are being investigated for their use in a wide variety of renewable energy applications. Their unique physical properties contribute to desirable traits such as a high carrier mobility, strong optical absorption and tunable electronic band gap. Unfortunately, due to variability in certain parameters, SWCNTs are limited in their application. The major drawback is that SWCNTs are variable in size and type and typical synthetic methods are not selective. As a result, selective methods must be developed in order to sort these tubes and extract those which are desirable for a particular application. Though there are several …


A Complex Legacy Of Contamination In Urban Estuarine Systems, Michael A. Kruge Sep 2016

A Complex Legacy Of Contamination In Urban Estuarine Systems, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Industrialized urban waterways have typically suffered decades of contamination, varying in source and intensity as manufacturing and transportation practices evolved. The U.S. Environmental Protection Agency designates locales with particularly severe contamination as Superfund sites. Among these, the Gowanus Canal and lower Passaic River in the New York/New Jersey harbor estuary illustrate a complex range of contamination types.

The 2.2 km Gowanus Canal, with sluggish circulation driven mostly by tides, accumulated fine-grained sediments (average thickness of 3 m) highly enriched in organic carbon (OC, mean 11 % but up to 49 %) derived from hydrocarbons, sewage, coal, char, and biomass, along …


Hydraulic And Electrokinetic Delivery Of Remediants For In-Situ Remediation, Ahmed I. A. Chowdhury Sep 2016

Hydraulic And Electrokinetic Delivery Of Remediants For In-Situ Remediation, Ahmed I. A. Chowdhury

Electronic Thesis and Dissertation Repository

Nano-scale zero valent iron (nZVI) has shown promising mobility and in-situ reactivity with chlorinated volatile organic compounds when injected into saturated porous media. The current study evaluated nZVI mobility and subsequent reactivity with in-situ contaminants in a variably saturated porous media. The nZVI particles, synthesized onsite at subzero temperatures, demonstrated complete trichloroethene (TCE) degradation within the target area. Furthermore, a three dimensional finite difference model (CompSim) was utilized to investigate nZVI mobility in variably saturated zones. Model predicted well head data were in very good agreement with field observations. Simulation results showed that the injected slurry migrated radially outward from …


Expanding The Applicability Of Raman Spectroscopy For Monitoring Photocatalytic Degradation, Franklyn Wallace Sep 2016

Expanding The Applicability Of Raman Spectroscopy For Monitoring Photocatalytic Degradation, Franklyn Wallace

Mahurin Honors College Capstone Experience/Thesis Projects

Compared to other types of wastewater pollutants, dangerous chemical compounds such as pharmaceuticals, pesticides, and herbicides are difficult to remove and consequently being detected (at least in part because detection limits have decreased) in drinking water at increasing concentrations. Photocatalytic degradation degrades harmful compounds to innocuous end products using energy from light. Although it is effective and cost-efficient, the underlying chemical mechanisms are not understood well enough to ensure that dangerous intermediate products are not formed during the degradation process. Raman spectroscopy can be used to analyze photocatalytic degradation reactions in real time, identifying intermediate products based on spectral features. …


A Comparison Of Solvent And Water-Borne Alkyd Coatings And The History Of Voc Regulations In The United States, Molly Elise Burns Sep 2016

A Comparison Of Solvent And Water-Borne Alkyd Coatings And The History Of Voc Regulations In The United States, Molly Elise Burns

Master's Theses

A Comparison of Solvent and Water-Borne Alkyd Coatings Abstract

Conventional solvent based alkyd coatings have gone out of favor due to concerns over volatile organic compound (VOC) content. However, due to recent focus on renewable raw materials, alkyds are making a comeback in waterborne form. Water based alkyd coatings are known to have poor shelf stability and corrosion resistance, as well as other problems during the formulation process. This project focused on comparing solvent borne to two types of water-borne alkyds, water reducible alkyds and alkyds emulsions. The purpose was to understand the differences between the three types of alkyds …


Persistence Of Trace Organic Contaminants From A Commercial Biosolids-Based Fertilizer In Aerobic Soils, Travis A. Banet, Jihyun R. Kim, Michael L. Mashtare Aug 2016

Persistence Of Trace Organic Contaminants From A Commercial Biosolids-Based Fertilizer In Aerobic Soils, Travis A. Banet, Jihyun R. Kim, Michael L. Mashtare

The Summer Undergraduate Research Fellowship (SURF) Symposium

Municipal biosolids are recycled as agricultural fertilizers. Recent studies have raised concerns due to the presence of emerging contaminants in municipal biosolids. Previous research suggests that these contaminants have the potential to reside in biosolids-based fertilizers that are commercially distributed. Use of these products in urban/suburban areas may provide a pathway for these contaminants to enter ecosystems and impact human and environmental health. Soils from Purdue University’s community garden and MiracleGro Potting Mix were chosen to represent commonly used urban/suburban growth media. Triclosan, triclocarban, and methyl parabens were selected as compounds of interest for this study. A heat treated commercial …


The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii Aug 2016

The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii

Graduate Theses and Dissertations

Organic matter (OM) in the environment acts as a nutrient, but may also act as a transport vector for harmful chemical compounds and bacteria. Acetate is a labile form of OM produced during fermentation in anaerobic lagoons used to store animal fecal-waste from concentrated animal feeding operations (CAFOs). Dry and liquid fertilizers from CAFOs pose a threat to groundwater by introducing excessive amounts of nutrients (e.g. OM, nitrate and ammonia), metals, and antibiotic compounds. In the epikarst of Northern Arkansas in the Buffalo River watershed additional input of labile dissolved organic carbon (DOC) from liquid CAFO waste-fertilizers was hypothesized to …


The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz Aug 2016

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …


Multiple New-Particle Growth Pathways Observed At The Us Doe Southern Great Plains Field Site, Anna L. Hodshire, Michael J. Lawler, Jun Zhao, John Ortega, Coty Jen, Taina Yli-Juuti, Jared F. Brewer, Jack K. Kodros, Kelley C. Barsanti, Dave R. Hanson, Peter H. Mcmurry, James N. Smith, Jeffery R. Pierce Jul 2016

Multiple New-Particle Growth Pathways Observed At The Us Doe Southern Great Plains Field Site, Anna L. Hodshire, Michael J. Lawler, Jun Zhao, John Ortega, Coty Jen, Taina Yli-Juuti, Jared F. Brewer, Jack K. Kodros, Kelley C. Barsanti, Dave R. Hanson, Peter H. Mcmurry, James N. Smith, Jeffery R. Pierce

Civil and Environmental Engineering Faculty Publications and Presentations

New-particle formation (NPF) is a significant source of aerosol particles into the atmosphere. However, these particles are initially too small to have climatic importance and must grow, primarily through net uptake of low volatility species, from diameters ∼ 1 to 30–100 nm in order to potentially impact climate. There are currently uncertainties in the physical and chemical processes associated with the growth of these freshly formed particles that lead to uncertainties in aerosol-climate modeling. Four main pathways for new-particle growth have been identified: condensation of sulfuric-acid vapor (and associated bases when available), condensation of organic vapors, uptake of organic acids …


Possible Sources And Impacts Of Biochar Water Extractable Organic Compounds On Aquatic Microorganisms, Cameron Russell Smith Jul 2016

Possible Sources And Impacts Of Biochar Water Extractable Organic Compounds On Aquatic Microorganisms, Cameron Russell Smith

Chemistry & Biochemistry Theses & Dissertations

Smokeless biomass pyrolysis with application of biochar as a soil amendment could be a significant approach for carbon sequestration to possibly control climate change for energy and environmental sustainability. If biochar were to be utilized as a soil amendment and a carbon sequestration agent at Gt C scales, the release of potentially toxic compounds into soils and associated hydrological systems, through soil rainwater runoff and leaching, might have negative consequences, in both agro-ecosystems and aquatic environmental systems. Therefore, the main focus of this dissertation was to study the sources and chemical composition of biochar water extractable (soluble) organic compounds and …


Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman Jun 2016

Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging …


Carbon Nanotubes Affect The Toxicity Of Cuo Nanoparticles To Denitrification In Marine Sediments By Altering Cellular Internalization Of Nanoparticle, Xiong Zheng, Yinglong Su, Yinguang Chen, Rui Wan, Mu Li, Haining Huang, Xu Li Jun 2016

Carbon Nanotubes Affect The Toxicity Of Cuo Nanoparticles To Denitrification In Marine Sediments By Altering Cellular Internalization Of Nanoparticle, Xiong Zheng, Yinglong Su, Yinguang Chen, Rui Wan, Mu Li, Haining Huang, Xu Li

Department of Civil and Environmental Engineering: Faculty Publications

Denitrification is an important pathway for nitrate transformation in marine sediments, and this process has been observed to be negatively affected by engineered nanomaterials. However, previous studies only focused on the potential effect of a certain type of nanomaterial on microbial denitrification. Here we show that the toxicity of CuO nanoparticles (NPs) to denitrification in marine sediments is highly affected by the presence of carbon nanotubes (CNTs). It was found that the removal efficiency of total NOX-N (NO3-N and NO2-N) in the presence of CuO NPs was only 62.3%, but it …


Conversion Of Cafo Manure Into A Slow-Release Fertilizer, Richard Allan Williams Iii May 2016

Conversion Of Cafo Manure Into A Slow-Release Fertilizer, Richard Allan Williams Iii

Honors Projects

Alginate polymer is known to form gel through the process of Ionotropic gelation. By use of extrusion and diffusion setting manure was encapsulated into gel beads. These beads were then tested to determine their potential for further testing as a manure treatment process. From the limited data in this preliminary study, it appears as though there is potential for further testing of alginate beads as a treatment process for manure. The treatment is potentially valuable because of the ease of filtration of the alginate beads, the low cost of transportation of the dehydrated beads, and because the limited data suggests …


Effects Of Cigarette Butts On Coastal Waters: An Elemental Analysis Of Seawater From St. Simon’S Island, Katherine Adorati May 2016

Effects Of Cigarette Butts On Coastal Waters: An Elemental Analysis Of Seawater From St. Simon’S Island, Katherine Adorati

Honors Theses

Cigarette litter can have detrimental effects on the environment, specifically when taking into account that over 4.5 trillion cigarette butts are littered every year. Within seawater, trace elements present in cigarettes may leach into the ocean, having damaging effects on the marine ecosystem. The goal of this research was to investigate if elemental contaminants leached from cigarette litter are significant in samples of seawater collected near St. Simon’s Island at both high and low tides, surrounding a beach party during the Florida/Georgia football game which occurred on November 1, 2014. Samples were collected in the months prior to and during …


Novel Methods And Sensors For The Analysis Of Trace Chemicals With Potential Environmental Applications, Samuel Mason Rosolina May 2016

Novel Methods And Sensors For The Analysis Of Trace Chemicals With Potential Environmental Applications, Samuel Mason Rosolina

Doctoral Dissertations

The work in this dissertation focuses on the detection and analysis of trace chemicals in biological and environmental samples. Methods for the electrochemical detection of heavy metals Cd(II) [cadmium] and Pb(II) [lead], and the catalytic metal Pd(II) [palladium] in pharmaceutical ingredients have been optimized without the necessity of sample pretreatment. The metals can be analyzed simultaneously as well as individually, and the study includes the first known instance of the use of anodic stripping voltammetry (ASV) to detect metals in dimethyl sulfoxide (DMSO) solutions. Another method, based on ASV, has been optimized and evaluated for the purpose of mercury(II) analysis …


Immobilization Of Heteropolyacids In Silica Gel, Opeyemi Adetola May 2016

Immobilization Of Heteropolyacids In Silica Gel, Opeyemi Adetola

Electronic Theses and Dissertations

Silica gels containing incorporated heteropolyacids (HPAs) were synthesized in acidic media by co-condensation of tetraethoxysilane (TEOS) with phosphotungstic or phosphomolybdic acids using sol-gel technique. Effect of the synthesis conditions on their structure and morphology was studied. Yields of modified materials were some lower as compared to non-modified silica gels. All materials were mesoporous but contained micropores in their structures. Presence of bands of Keggin’s structures in FT-IR spectra along with absence of XRD patterns of crystalline HPAs confirmed their fine incorporation into silica network. Particle sizes of modified materials were 800-1100 nm excepting for W-containing sample obtained with trimethylstearylammonium chloride. …


Late Holocene Climate And Environmental Reconstruction Derived From The Asian Ice Core Array (Aica), Bjorn Grigholm May 2016

Late Holocene Climate And Environmental Reconstruction Derived From The Asian Ice Core Array (Aica), Bjorn Grigholm

Electronic Theses and Dissertations

Recent climate change has impacted natural and human systems across the Earth, emphasizing the need for greater understanding of both the existing and changing natural and anthropogenic forcing mechanisms and subsequent responses of the Earth’s climate system. High-resolution, multi-parameter ice core records retrieved and analyzed from two Asian Ice Core Array (AICA) sites, Geladaindong (central Tibetan Plateau) and Inilchek (central Tien Shan) were utilized to reconstruct atmospheric chemical concentrations and composition over the past ~100-500 years, improving the understanding of late Holocene climate and environmental variability in Asia. Both ice cores were analyzed for major and trace elements, major soluble …