Environmental Chemistry Commons^™

Mechanisms And Transients Involved In The Solar Conversion Of Petroleum Films In Aquatic Systems, Phoebe Z. Ray

LSU New Orleans Theses and Dissertations

The behavior of Deepwater Horizon crude oil and other sources of oil were investigated when exposed to sunlight in aquatic systems under environmentally relevant conditions. This research decoupled the abiotic and biotic weathering modifications of oil by focusing solely on the photochemical transformations of oil in aquatic systems. Photochemical rates and mechanisms were measured through the determination of reactive transients. Total hydroxyl radical formation was studied using high benzoic acid concentrations and varying exposure time. Titanium dioxide (TiO₂) nanomaterials were added to the system in an effort to determine if the photocatalyst would enhance oil photodegradation. Photochemical production …

Using Stable Isotopes To Quantify Nitrogen Fates In Container Plants, Sam Raimann, Greg Michalski, Michael V. Mickelbart

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, in the agriculture field, it is not yet known the accurate amount of Nitrogen in fertilizer that plants take up. This statistic, known as the Nitrogen Use Efficiency is currently known to be within the 30-50% range (Lea-Cox and Ross, 2001). This is very important figure to know and it is a figure that can be improved, and therefore much time, energy, and resources can be saved. This research project will use concepts involving stable isotopes to examine red maple plant material and the soilless media that the plants were grown in. Three different isotope-labelled fertilizer treatments will be …

Evaluating Contaminants Of Emerging Concern In Commercial Biosolid-Based Fertilizers, John Hemmerling, Michael L. Mashtare, Linda S. Lee

The Summer Undergraduate Research Fellowship (SURF) Symposium

The production and popularity of commercially available biosolid-based fertilizers are increasing because of their economic, environmental, and plant nutrition benefits, particularly in urban and suburban areas. Because biosolid-based fertilizers are derived from waste water treatment plant residuals, we hypothesized that there is the potential for micropollutants to persist in these products. Their presence would be of particular concern due to their potential impact on human and ecological health and risk of bioaccumulation. This study involves quantifying contaminants of emerging concern in three biosolid-based fertilizers, and 2 non-biosolid-based fertilizers, a composted animal manure and an organic compost. Our extraction method employed …

Laboratory Evaluation Of Black Carbon Deposition Onto Snow And Transport Via Snowmelt, Larry D. Hermanson, Joshua P. Schwarz

STAR Program Research Presentations

Black carbon (BC) is an aerosol material produced by incomplete combustion of fossil fuels and biomass. BC has been shown to be the second most important anthropogenic climate warming agent after carbon dioxide due to its ability to absorb solar radiation, influence cloud behavior, and accelerate snow melt. BC in otherwise clean snow can significantly reduce its reflectivity. In order to learn about the significance of BC contamination in snow, we explored the deposition of BC onto snow and the transport of BC in snow during snowmelt. A Single Particle Soot Photometer (SP2), was used to measure the concentration and …

Characterization Of Organic Carbon In Sediments From Old Rifle, Co, A Former Uranium Mill, Francis Michael Tee, Morris Jones, Sharon Bone, Michael Schaefer, Scott Fendorf, John Bargar

STAR Program Research Presentations

Characterization of sediments from Old Rifle, CO, a former uranium mill

More than 34 million gallons (~129 million liters) of groundwater are contaminated with uranium at Old Rifle, Colorado – a former uranium-processing site that operated until 1958. The original Department of Energy strategy for remediation, involving natural flushing of U from the groundwater through mixing with surface water, has not been as successful as predicted. The uranium plume is replenished when insoluble U(IV) is oxidized to the more mobile U(VI). Relatively thin pockets of silt-, clay-, and organic-rich sediments contain reduced uranium, iron and sulfur and are referred to …

Ice Caves On Extraterrestrial Bodies: What Are The Prospects For Speleogenesis And Detection?, Penelope J. Boston

The International Workshop on Ice Caves

Potential mechanisms for creating cavities in icy extraterrestrial bodies have been tentatively explored by several authors. On one hand we have examples of mechanisms that create caves in water ice here on Earth. In addition, there may be unique mechanisms on other Solar System objects that do not occur on Earth but might produce cavities, e.g. sublimation of comets upon perihelion passage. The methods of detecting such cavities depend upon the nature of the icy body in question, the potential for orbital or landed missions to visit those bodies in the future, and remote or landed methods for detecting the …

Heat Release Of Polyurethanes Containing Potential Flame Retardants Based On Boron And Phosphorus Chemistries, Vladimir Benin, Bastien Gardelle, Alexander Morgan

Chemistry Faculty Publications

Using a polyurethane of methylene diphenyl isocyanate and 1,3-propane diol, several new non-halogenated aromatic boron and phosphorus flame retardants were evaluated for heat release reduction potential using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods, and were then analyzed via spectroscopic methods to determine if the flame retardant was still present in the final product. PCFC testing on the resulting products showed that the flame retardant molecule can have different effects on heat release depending upon how it is mixed into the polyurethane. Some …

Determination Of Corrosion Inhibitor Lubricity Improver In Jet Fuel By Liquid Chromatography-Electrospray Ionization Mass Spectrometry, David W. Johnson, Milissa Flake, Ryan Adams

Chemistry Faculty Publications

Military jet fuel (JP-8) is very similar to commercial jet fuel (Jet A) except for the presence of three additives, fuel system icing inhibitor, corrosion inhibitor–lubricity improver (CI-LI), and antistatic additive, which are added to improve characteristics of JP-8. Of particular interest is the CI-LI additive; the most common active ingredient is a dimer of linoleic acid. This article focuses on quantification of the active ingredient in the CI-LI additive by liquid chromatography–mass spectrometry (LC–MS). This method will allow the determination of CI-LI content in military jet fuel samples.

Carbon Sequestration In Tidal Salt Marshes And Mangrove Ecosystems, Carlos Eduardo Quintana-Alcantara

Master's Projects and Capstones

Wetlands are dynamic systems that provide support to vital environmental functions and services. Wetlands take part in the global carbon cycle by holding organic carbon in biomass, soils and sediments. In recent years, the wetland carbon sequestration capacity has been researched worldwide due to the increase of the concentrations of greenhouse gasses implicated in global warming and climate change. Although coastal wetlands release the greenhouse gasses carbon dioxide, methane and nitrous oxide, these ecosystems maintain high performance in offsetting significant amounts of atmospheric carbon. This paper investigated the carbon sequestration capacity of coastal wetland ecosystems summarizing the environmental conditions and …

Co2 Reduction Under Periodic Illumination Of Zns, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The photoreduction of CO₂ to formate (HCOO^–) in sphalerite (ZnS) aqueous suspensions is systematically studied in the presence of Na₂S hole scavenger. A series of cut-on filters at λ_cut-on ≥ 280, 295, 305, 320, and 400 nm are used to measure the reaction rate of formate production. The dependence of the measured reaction rates on λ_cut-on indicates that a wavelength of λ = 345 nm is associated with the actual bandgap of the semiconductor nanocrystallites suspended in water. The results from apparent quantum yield measurements during periodic illumination experiments suggest that (1) valence-band …

Tetracyclines In Swine Waste, Natalie Kaye Jones

Masters Theses & Specialist Projects

Antibiotics are added to animal feeds as prophylactic agents and to encourage weight gain in livestock. However, there is concern that the widespread use of antibiotics in animal agriculture encourages for the selection of resistance genes and has contributed to the rise of multiply antibiotic resistant strains of pathogenic bacteria. For this reason, there is interest in quantifying antibiotics in environmental samples. The determination of three antibiotics in swine waste, namely chlortetracycline, tetracycline and oxytetracycline, using LC-MS with electrospray ionization is presented here in. Antibiotics from swine waste were quantified across the lifespan of the swine. Trends were present in …

Removal Of Arsenic Using Iron Coated Limestone, Anitha Swarna

Masters Theses & Specialist Projects

Arsenic contamination in drinking water is a severe problem worldwide. The best way to prevent hazardous diseases from chronic arsenic exposure is to remove the exposure. Efforts to remediate arsenic in drinking water have taken two tracks. One is to provide surface or shallow well water sources as an alternative to the arsenic contaminated deep wells. Another approach is to remove arsenic from the contaminated water. Different removal technologies like oxidation, chemical coagulation, precipitation, adsorption and others are available. There are problems and benefits associated with each of these approaches that can be related to cultural, socio-economic and engineering influences. …

Synthesis Of Perylenediimide-Functionalized Silsesquioxane Nanostructures, Lan Xu

Masters Theses & Specialist Projects

Organic semiconductors functionalized nanostructures are becoming as promising materials for electronic device applications including organic photovoltaics (OPVs). Perylenediimide (PDI) derivatives have also been known as one of the best n-type organic semiconductors. PDI derivatives can form bulk materials, which are both photochemically and thermally stable and have been widely used in various optoelectronic devices. Due to the formation of high electron mobility of crystalline domains, they prefer to incorporate into a silsesquioxane network. Here, we describe the potential applicability of perylenediimide functionalized silsesquioxane nanoribbons (PDI-dimethyl nanoribbons) as an acceptor for optoelectronic devices. We have developed synthetic procedures to make the …

Thermal Analysis Of Binding Of Organic Pollutants To Titanium Dioxide, Shashidhar Annarapu

Masters Theses & Specialist Projects

Conventional waste water treatment processes are not completely effective in removing highly stable organic compounds. Photocatalytic degradation on titanium dioxide is a possible alternative technique for many classes of these compounds. Several studies have been done by other researchers to study mechanisms of photocatalytic degradation, which occurs either through direct oxidation by holes or via indirect oxidation by radical messengers. Titanium dioxide can oxidize substrates directly through hole oxidation mechanisms or indirectly through free radical mechanisms. Substrates must bind onto the catalyst surface to undergo direct oxidation by holes. Thermogravimetric analysis (TGA) was performed on four different classes of compounds; …

Biogeochemistry Of Trace Elements In The Mixing Zone Of The Mississippi And Atchafalaya Rivers And Chemical Distributions As Affected By The Deepwater Horizon Blowout, Dongjoo Joung

Dissertations

Selected trace elements (TEs), dissolved organic carbon, and nutrients were studied in Louisiana Shelf waters including the Mississippi (MR) and Atchafalaya (AR) River plumes during periods of high, intermediate, and low river discharges. Seasonal variations in TEs were observed at low salinity, reflecting seasonal changes in the river water endmembers. Shelf surface water dissolved Mo, Cs, U, Ni, and Cu showed conservative behavior with minor scattering in some high salinity waters. Based on associated mixing experiments, nutrient and chlorophyll distributions, as well as surface-bottom concentration contrasts, the non-conservative behavior of TEs was variously related to colloidal flocculation (Fe, Cr), biological …

Environmental Impact Assessment Of The Missouri Mine, Christian Laursen, Waco Holve-Burk

College of Arts and Sciences Presentations

Gold mining in Idaho and other western states has left a legacy of heavy metal contamination. These metals enter the food chain via plants and water, and are toxic to living organisms. There is a need to identify and map the heavy metal contamination, and to track the fate and transport of heavy metals from one mine site to another via surface waters. Our hypothesis is that the severe contamination in the area of the Missouri Mine is not all from that site, but includes heavy metals transported in surface water from another mine to the northeast, in the Summit …

Ultraviolet Light Emitting Diode Use In Advanced Oxidation Processes, Kelsey L. Duckworth

Theses and Dissertations

Cleanup from a hazardous chemical release can result in large volumes of water containing hazardous materials, such as organophosphates. Unfortunately, this water cannot be treated in a municipal wastewater treatment plant without adversely affecting the performance of the plant. A known method for pretreating this water to prepare it for processing in a traditional treatment plant includes the addition of hydrogen peroxide, followed by ultraviolet (UV) light exposure to form reactive hydroxyl radicals which oxidize the chemical. Light emitting diodes (LEDs) are explored as a UV source as they are durable; compact; can be powered by low voltage, direct current …

Reduction Of Uranium By Bacterial Products, Adesanya A. Akinleye, Sharon Bone, John Bargar

STAR Program Research Presentations

The Old Rifle Mill Processing site at Rifle, CO, contains uranium contaminated groundwater. The presence of uranium is one of the major problems at Department of Energy legacy sites. There is an initiative for attenuation of uranium by the Department of Energy. Uranium undergoes oxidation/reduction reactions with the substances at the site. Uranium’s oxidation state determines its solubility and mobility in the aquifer. The oxidation reduction pathways at this site have mineralogical, microbial and geochemical components. Understanding the oxidation/reduction pathways of these components will allow for better predictions of the changes and movement of uranium.

Sulfide [S^2- ] and …

Determination Of Optical Properties Of Secondary Organic Aerosols Using Uv-Vis Spectroscopy, Vanessa Selimovic, Matthew E. Wise, John Shilling

CUP Undergraduate Research

• Aerosols interact differently with the atmosphere depending on:
• Composition
• Size
• Phase
• Reactivity
• Optical Properties
• Reactivity with atmosphere determines impact on Earth’s radiative budget

[excerpt]

Applying Green Chemistry Principles In The Electrophilic Bromination Of Indole-3-Acetic Acid, Kyle Murphy

Undergraduate Review

The goals of green chemistry are to reduce or eliminate the use of hazardous reagents, prevent the synthesis of toxic products and byproducts, and improve the overall efficiency of chemical reactions. Green chemistry is incredibly important today as chemical products are produced and used around the world, resulting in the use and generation of hazardous chemicals, and unintended consequences to human health and the environment. Figure 1 shows the 12 Principles of Green Chemistry1, developed by Paul Anastas and John Warner, which provide the framework for a sustainable future in the design of more efficient technologies to produce consumer products …