Environmental Chemistry Commons^™

De Novo Protein Binding To Zinc Oxide Through Biomineralization Pathways, Jean-Mark A. Francis

Theses and Dissertations

De novo proteins are structurally distinct from proteins found in nature and thus capable of having their amino acid sequence modified to accomplish tasks such as increasing protein-nanoparticle binding without unfolding or decomposing. Zinc Oxide nanoparticles are functionally distinct from their bulk counterparts and are widely used as semiconductors in a variety of fields such as medicine and agriculture. With demand for these nanoparticles increasing, environmentally sustainable methods of Zinc Oxide nanoparticle synthesis are being investigated as an eco-friendly alternative to currently utilized but environmentally hazardous chemical and physical techniques. This research investigates the binding characteristics between Zinc Oxide nanoparticles …

Air-Based Chemical Patient Decontamination Methodologies For Arctic Regions Using Methly Salicylate As A Chemical Agent Surrogate On A Litter-Bound Manikin, Marcus D. Shadd

Theses and Dissertations

This study evaluated a mobile air shower for patient decontamination without disrobing or rinsing, an alternative for Arctic conditions where water is scarce. A manikin in extreme cold weather gear was exposed to 10 µL of methyl salicylate (MeS), a sulfur mustard surrogate, and placed in a horizontal chamber on a military litter. Airborne MeS was measured using a ppbRAE 3000 detector to assess inhalation risk for the patient and decontamination team. Three methods were tested: an air-knife system, paper towels, and no decontamination, with 10 trials each (30 total). ANOVA analysis showed significant reductions in airborne MeS with air-knife …

Evaluating Dry Air Personnel Decontamination Of Methyl Salicylate As A Chemical Agent Surrogate In Extreme Cold Environments To Reduce Airborne Risks Using A Manikin, Lance E. Campbell

Theses and Dissertations

This research investigated a mobile air shower as an alternative to water washing for personnel chemical decontamination in Arctic environments, where traditional methods like disrobing and rinsing are impractical. Interest in Arctic operations has grown with recent U.S. military focus on strategic advancements by Russia and China, yet research on air shower effectiveness for chemical decontamination remains limited. This study examined whether a commercial off-the-shelf air shower could effectively decontaminate methyl salicylate (MES), a surrogate for chemical warfare blister agents, from a manikin outfitted in military cold-weather gear. Researchers used a ppbRAE 3000 photo-ionization detector to measure MES concentrations following …

Molecular Scale Investigations Of Interactions Between Pfas And Concrete, Eric E. Keeler

Theses and Dissertations

Per- and polyfluoroalkyl substances (PFAS), widely referred to as “forever chemicals,” exhibit high environmental persistence and potential health risks due to their robust carbon-fluorine bonds. These substances are prevalent in aqueous film-forming foams (AFFF), used in industrial and military applications, and are known to contaminate environmental surfaces, including concrete. This study aims to characterize the molecular-level interaction energies of six PFAS species—PFOA, PFOS, PFHxS, PFHxA, 6:2 FTS, and PFBS—with calcium silicate, a key component of concrete, using density functional theory (DFT) calculations. Change in Gibbs free energy (ΔG) was determined for each of the interactions, revealing negative ΔG values for …

Atmospheric Water Generation: Bacterial And Inorganic Chemical Quality, Garrett E. Stanley

Theses and Dissertations

This study investigated the quality of untreated water collected from a vapor compression-based atmospheric water generator (AWG) operated outdoors in Dayton, Ohio. The concentrations of bacterial and chemical constituents were determined. The concentration of culturable bacteria was between 200 and 2300 CFU/mL, significantly higher than the reference levels described in recreational and drinking water quality guidance. Three discrete bacteria phenotypes were visually identified; two were yellow in color, rod-shaped and gram-negative while the third was milky white, circular, and gram-positive. Chemical analysis on 15 randomly selected samples revealed the presence of Barium (average = 0.16 mg/L), Magnesium (0.08 = mg/L), …

High Throughput, Solid Sample Analysis With Cone-Based Mass Spectrometric Ionization Sources, Emily J. Wiggins

Theses and Dissertations

The widespread presence of environmental and consumer-product contaminants (e.g. trace metals, opium alkaloids) has underscored the need for rapid, reliable, and high-throughput analytical techniques that are capable of handling complex solid samples. While traditional mass spectrometric (MS) methods tend to have high sensitivity and accuracy, they often require labor-intensive and time-consuming sample preparation steps that limit throughput and field applicability. This thesis investigates the use of 3D-Printed Cone Spray Ionization-Mass Spectrometry (3D-PCSI-MS) as an ambient ionization technique for the direct screening of contaminants from solid matrices, eliminating the need for traditional sample preparation and allowing for real-time analysis.

In …

Advanced Oxidation Of Tert-Butanol With Ultraviolet Light Emitting Diodes And Hydrogen Peroxide, Lauren R. Mainolfi

Theses and Dissertations

Tert-butanol (TBA), a versatile chemical widely used in industrial processes, poses exposure risks through inhalation, ingestion, and skin contact. Environmental contamination, often from industrial activities, emphasizes the importance of robust waste management and monitoring to protect water supplies from potential TBA migration and ensure drinking water safety. This study employed hydrogen peroxide (H2O2): TBA molar ratios of 100, 200, 400, and 500:1 in a Continuous Flow Stirred-Tank Reactor (CSTR) with UV-LED as the TBA degradation mechanism in an Advanced Oxidation Process (AOP). The UV-LEDs and H2O2 were synergistically employed to generate hydroxyl radicals in an advanced oxidation process. Gas chromatography–mass …

Advanced Oxidation Of Methyl Tert Butyl Ether With Ultraviolet Light Emitting Diodes, Aaron R. Neal

Theses and Dissertations

Methyl Tert-Butyl Ether (MTBE) is a volatile, soluble, organic compound introduced to gasoline within the United States as a fuel oxygenator in 1979. MTBE is a common groundwater pollutant due to its high water solubility and resistance to bio-degradation; it commonly infiltrates groundwater sources via leaking underground storage tanks or fuel spills. This research employed ultraviolet light emitting diodes (UV-LEDs) and hydrogen peroxide (H₂O₂) induced advanced oxidation process (AOP) to treat MTBE contaminated water at the bench scale. Using four H₂O₂:MTBE molar peroxide ratios (100:1, 200:1, 400:1, 500:1), MTBE degradation was induced …

Thin-Film Nanocomposite Membranes With Alumina Nanoparticles For Textile Wastewater Treatment Applications, Amr Mohamed Tayel

Theses and Dissertations

Thin-film nanocomposite (TFN) membranes are gaining great interest in industrial wastewater treatment due to their superior performance, especially for higher water flux and pollutants’ rejection, as well as improved chemical, thermal and mechanical stabilities, compared to other types of membranes. The performance of TFN membranes can be enhanced using different types of nanofillers, among which ceramic nanomaterials, such as Al2O3, offer a promising potential for applications involving treatment of industrial wastewater such as textile effluents, and this is due to their stability, hydrophilicity, and relative low cost. The study of the TFN membrane properties and structure allows the optimization and …

The Effect Of The Carbon Nanotubes’ Surface Area On The Morphology And Performance Of Cellulose Acetate Nanocomposite Membranes In Nanofiltration Applications, Nouran Elbadawi

Theses and Dissertations

Population increase and climate change have significantly affected the availability of fresh water for consumption. Studies by UNESCO showed that more than 28% of the world population didn’t have access to clean safe drinking water in 2020. This situation is expected to get more serious over the coming 30 years with the limited availability of natural fresh water sources. The need to find solutions from alternative non-freshwater resources for drinking or irrigation is becoming a necessity. Within the context of desalination technologies, thousands of investigations are conducted to find the cheapest most efficient way of water treatment aiming at expanding …

Biopolymer-Coated Magnetite Nanoparticles For The Removal Of Emerging Contaminants From Aqueous Solutions, Hebatullah Farghal

Theses and Dissertations

Abstract

Biopolymers are gaining interest as promising materials for water purification due to their functionality, biodegradability, abundance, and safe use. In this work, three biopolymer-based systems were developed as adsorbents for removing emerging contaminants from water. The first system of biopolymeric nanocomposites was synthesized by coating chitosan/xylan biopolymeric nanocomposites on magnetite nanoparticles (CsXM) to facilitate their separation from water via a magnetic field. The prepared mesoporous CsXM nanocomposite was thermally stable and possessed a particle size of 11 nm and a neutral to slightly negative charge over the studied pH range of about 3 to 10. The nanocomposite efficiently removed …

Carbon Dioxide Capture Potential Of Chitosan-Nanocrystalline Cellulose Aerogel Composite Materials: Synthesis, Functionalization, And Characterization, Victor Oghenekohwo

Theses and Dissertations

The carbon dioxide capture technology has been established as an invaluable player in the current global efforts to allay the warming of the planet and climate change. In this connection, the study centers on the valorization of waste organic materials for the application described herein. The sorbents, sourced from a combination of by-products of food processing and agricultural residue waste products, viz. seafood waste and sugarcane bagasse, showed prospects for selective carbon dioxide capture, adsorbing up to 5.78 mg/g of the gas at 273 K and 2.82 mg/g at 298 K, as observed on the Micromeritic ASAP 2020 surface area …

Adsorption Of Antibiotics In Wastewater By Stevia Rebaudiana Zinc Oxide Nanoparticles, Hania Guirguis

Theses and Dissertations

Green zinc oxide nanoparticles (ZnO NPs), synthesized using Stevia rebaudiana extract, are investigated as novel adsorbents for the removal of the antibiotics ciprofloxacin (CIP) and tetracycline (TET) from water. The green ZnO NPs were synthesized using a novel, rapid and ecofriendly technique that utilized a natural source with high sugar content as a reducing agent and a less energy intensive approach that did not require annealing or calcination at high temperatures. The particles are mesoporous, with a hexagonal wurtzite structure, a BET surface area of 15.28 m2/g and a size range of 37.36-71.33 nm. At pH 5, the green ZnO …

Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy, Rongrong Wu Cohen

Theses and Dissertations

The widespread pollution of mercury motivates research into its atmospheric chemistry and transport. Gaseous elemental mercury (Hg(0)) dominates mercury emission to the atmosphere, but the rate of its oxidation to mercury compound (Hg(II)) plays a significant role in controlling where and when mercury deposits to ecosystems. Atomic bromine is regarded as the main oxidant for Hg(0) oxidation, known to initiate the oxidation via a two-step process in the atmosphere – formation of BrHg (R1) and subsequent reactions of BrHg with abundant free radicals Y, i.e., NO2, HOO, etc. (R2), where the reaction of BrHg +Y could also lead to the …

Functionalized Biochar Electrodes For Asymmetric Capacitive Deionization, Hellen Stephanie

Theses and Dissertations

Electrosorption-based capacitive deionization (CDI) has become a viable process for brackish water desalination and defluoridation. In this study, activated Douglas fir biochar is used as a low-cost electrode material with adsorption capacity comparable to activated carbon obtained from biomass precursors. Adding functional groups to the activated biochar enhanced salt removal capacity, providing cation and anion selectivity. The functionalized electrodes were prepared by Nafion, titanium isopropoxide, and p-phenylenediamine treatment, respectively, which introduced sulfonate, titanium dioxide and amine functional groups to the electrode surface. These modification methods are versatile and can be easily performed without sophisticated laboratory environment. Modified biochar electrodes …

Insights Into Molecular Recognition And Reactivity From Molecular Simulations Of Protein-Ligand Interactions Using Md And Qm/Mm, Jerrano L. Bowleg

Theses and Dissertations

In this thesis, we have employed two computational methods, molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) MD simulations with umbrella sampling (US), to gain insights into the molecular mechanism governing the molecular recognition and reactivity in several protein-ligand complexes. Three systems involving protein-ligand interactions are examined in this dissertation utilizing well-established computational methodologies and mathematical modeling. The three proteins studied here are acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1). These enzymes are known to interact with a variety of ligands. AChE dysfunction caused by organophosphorus (OP) chemicals is a severe hazard since AChE is …

Phosphorus Enriched Modified-Douglas Fir Biochar As A Soil Amendment, Beatrice Arwenyo

Theses and Dissertations

Biochar application as a soil additive is gaining global acceptance. In this era of climate change, biochar use for improved soil productivity is not just a sustainable eco-friendly substitute to synthetic fertilizer, but a noble contributor to the fight against climate change. Although biochar has been accredited with some environmental and agricultural benefits, most studies concentrated on agricultural and biowaste products as feedstocks. This research was designed to explore P-enriched modified-Douglas fir biochar potential as a soil additive. Using corn as a test crop, greenhouse studies were performed on acidic sandy soil, comparing phosphorus enriched modified-Douglas fir biochar efficacy to …

Engineered Nanostructured Nitrogen-Doped Carbon Network (Ndc) Electrodes With Unprecedented Cycling Stability For Water Capacitive Deionization In Harsh Conditions, Soha Essam Anwar

Theses and Dissertations

Capacitive deionization (CDI) is a feasible low-cost desalination technique for low-to-medium (brackish) salinity water. However, cycling stability and regeneration of the CDI electrodes are the bottlenecks hindering the practical application of the technology on large scale. Oxidation of the electrodes during the sequential adsorption-desorption processes is one of the most challenging problems hindering their long-term cycling performance. Herein, we demonstrated the ability to design and fabricate exceptionally stable CDI electrodes via a one-pot pyrolysis protocol. The optimized pyrolysis of nitrogen-carbon precursors at different temperatures enabled the fabrication of carbon materials with a controlled amount nitrogen dopant (NDCs) with exceptional cycling …

The Effect Of Amino Acids And Molar Peroxide Ratio On The Oxidation Of 2,4 Dinitroanisole In An Ultraviolet Light Emitting Diode/H2O2 Advanced Oxidation Process, Jeffry P. Hart

Theses and Dissertations

2,4 Dinitroanisole (DNAN) is an organic insensitive munition that is a likely candidate to replace trinitrotoluene (TNT) for a variety of purposes. Advanced Oxidation Processes (AOPs) are a promising method that have the potential to reduce a variety of persistent chemicals, however, the performance of these systems may be degraded by co-contaminants in the influent. In this contribution, DNAN, with casamino acids as a co-contaminant, was oxidized with Ultraviolet (UV) Light Emitting Diodes (LEDs) with hydrogen peroxide (H₂O₂) in an AOP in a laboratory. The UV/ H₂O₂ AOP was capable of degrading DNAN …

Analysis Of Organochlorine Pesticides Levels In Irrigation Water From Various Water Sources Across Egypt, Omar Tarek Khairy

Theses and Dissertations

Organochlorine pesticides are extensively used in agriculture to cope with the world’s increasing population and demands for nutrition. This class of pesticides poses a serious risk to human health upon chronic exposure to elevated levels. Determination of organochlorine pesticides levels in water has been extensively covered in literature in Egypt and other parts of the world. The need for up-to date data and statistical information regarding the levels of organochlorine pesticides in water is ever increasing. These compounds, although a lot have been prohibited from use decades ago, can still be detected in trace levels in water due to their …

Development Of Photocatalysts Supported On Graphitic Carbon Nitride For The Degradation Of Organic Water Pollutants, Atanu Giri

Theses and Dissertations

Graphitic carbon nitride (g-C₃N₄) heterojunction composites with the semiconducting metal oxides, CeO₂, ZnO and TiO₂ are prepared in situ by co-calcination of the precursor materials or by a solvothermal method. The structural, morphological and the optical properties of the prepared materials are studied using various microscopy and spectroscopy techniques. The synthesized composite materials, CeO₂/g-C₃N₄, ZnO/g-C₃N₄ and TiO₂/g-C₃N₄ are more efficient in the photocatalytic degradation of the water pollutants indigo carmine (IC) and atrazine than the pure metal oxide, g-C …

Exploring The Effects Of Different Classroom Environments On The Learning Process. Synthesis Of Thiazole-Linked Porous Organic Polymers For Co2 Separation And Nitro-Aromatics Sensing., Davide D'Urbino

Theses and Dissertations

When attempting to study the learning process of undergraduate chemistry student, the classroom and any interaction that take place within it constitute the social context of interest. By studying how different approaches can foster different classroom environments, it is possible to approach course design from an informed and scientifically sound perspective. Thus, it becomes necessary to identify and quantify the factors that have a positive or negative effect on the classroom environment. Social comparison concerns, comfort levels and self-efficacy have been shown to be social factors that affect each other as well as the learning process and have therefore been …

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …

Systematic Postsynthetic Modification Of Nanoporous Organic Frameworks And Their Performance Evaluation For Selective Co2 Capture, Timur Islamoglu

Theses and Dissertations

Porous organic polymers (POPs) with high physicochemical stability have attracted significant attention from the scientific community as promising platforms for small gas separation adsorbents. Although POPs have amorphous morphology in general, with the help of organic chemistry toolbox, ultrahigh surface area materials can be synthesized. In particular, nitrogen-rich POPs have been studied intensively due to their enhanced framework-CO₂ interactions. Postsynthetic modification (PSM) of POPs has been instrumental for incorporating different functional groups into the pores of POPs which would increase the CO₂ capture properties. We have shown that functionalizing the surface of POPs with nitro and amine groups …

Comparing Three Methods For Estimating Ozone Depleting Substance Substitute Greenhouse Gases: Case Study Of The New York City Region, Wallace A. Murray Iii

Theses and Dissertations

This thesis evaluates the United States Environmental Protection Agency (EPA) method for estimating emissions from one source, Ozone Depleting Substances Substitutes (ODS substitutes) by comparing results for the New York City Metropolitan Statistical Area (NYC-MSA) with results from two other methodologies. The EPA’s method utilizes population data and GDP data to estimate and geographically allocate emissions, with little regard for the geographies of industrial activity. The two alternative methods use data for industrial employment and activity to provide results for comparison and perhaps a more accurate accounting and allocation of emissions throughout the NYC-MSA.

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 …

Traceability Implementation In Organic Farming: Case Study, Chamomile Tea Production, Shaima Ibrahim

Theses and Dissertations

Implementing a traceability plan in an herbal production plant is a complex task. In this study an attempt to integrate food safety, quality and traceability through the different stages of the organic German Chamomile (Matricaria recutita) production chain was made. First, all the current relevant international laws, regulations and standards regarding traceability, safety and quality, with emphasis on how and why they are necessary for any food production chain, were set forward. Second, physico-chemical and microbiological analyses were run throughout the different processing stages of production, for four different Chamomile batches produced over the same season using the same farming …

Comparative Kinetics And Distribution To Target Tissues Of Organophosphates Using Physiologically-Based Pharmacokinetic Modeling, Rick E. Vermillion

Theses and Dissertations

A physiologically-based pharmacokinetic model has been developed to examine the effects of organophosphates on the levels of acetylcholine in different tissues throughout the mammalian body. Many organophosphate-like chemical and kinetic characteristics are tested without reference to a specific chemical. Characteristics include partition coefficients, metabolic constants, the inhibition coefficient, the aging rate, and the regeneration rate. Two separate exposure scenarios are tested and compared against a baseline. The baseline consists of a direct inhalation exposure. The first exposure scenario examines the effects of bronchial scrubbing (via inhalation) and the second scenario is a study of dermal exposures and compares the levels …

Oxygenation Of The Root Zone And Tce Remediation: A Plant Model Of Rhizosphere Dynamics, Ian F. Thompson

Theses and Dissertations

This study analyzes rhizosphere conditions that enhance the effective aerobic degradation of TCE in wetland bioremediation systems. A plant model was built using Stella 9.0 modeling software and uses numerical integration evaluation; it addresses movement of oxygen through plant vascular and aerenchymal systems, and into the rhizosphere where oxygen and other substrates influence bacteria. Methanotrophs and heterotrophs are assumed to be influential bacteria groups. Variations of humidity-induced-convection, methane, soil carbon, and copper concentrations are evaluated. Varying concentrations and hydraulic loadings of TCE are assessed with respect to TCE consumption rate and TCE treatment efficiency. Soil conditions most directly affected TCE …

Molecular Characterization Of Wetland Soil Bacterial Community In Constructed Mesocosms, Ethan C. Bishop

Theses and Dissertations

The use of wetlands to effectively remediate aquifers contaminated with chlorinated solvents is an emerging technique, which shows high promise. In order to better understand this process and test its legitimacy, a treatment wetland was constructed at Wright-Patterson AFB, Dayton, Ohio and, in a joint effort with Wright State University (WSU), has previously shown the effective removal of PCE. The purpose of this research was to characterize the soil bacterial community, pre-PCE injection, among three wetland plant species from the sedge family (Cyperaceae) within constructed wetland mesocosms and to identify any bacterial dominance. Carex comosa, Scirpus atrovirens, and Eleocharis erythropoda …