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Full-Text Articles in Chemistry

Extraction Of Neutron-Gamma Irradiated Diffusion Pump Oils, Cooper L. Tillman Aug 2024

Extraction Of Neutron-Gamma Irradiated Diffusion Pump Oils, Cooper L. Tillman

All Theses

This work successfully demonstrates solvent extraction methods for separation of oil from the by-products when two commercially available vacuum pump oils were exposed to an intense neutron and gamma-ray radiation environment. Nuclear fusion power at a commercial scale has accelerated the need for radiation resistant vacuum technology, such as oil-based diffusion pumps. Polyphenyl ether and aromatic silicone oils were irradiated at the Rhode Island Nuclear Science Center (RINSC) up to MGy absorbed doses with neutron and gamma-ray radiation. Solvent extractions were performed using hexane and isopropanol to characterize the oil extraction as a function of total absorbed dose. The by-products …


Prediction Of Pfoa And Pfos Toxicity Through Log P And Number Of Carbon With Comptox And Machine Learning Tools, Ahmed Dashtey, Patrick Mormile, Sandra Pedre, Stephany Maure Valdaliso, Walter Z. Tang Jul 2024

Prediction Of Pfoa And Pfos Toxicity Through Log P And Number Of Carbon With Comptox And Machine Learning Tools, Ahmed Dashtey, Patrick Mormile, Sandra Pedre, Stephany Maure Valdaliso, Walter Z. Tang

Department of Civil and Environmental Engineering Faculty Publications

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are two major groups of PFAS will be subjected to the Maximal Contamination Concentration (MCL) of 4 ng/l in drinking water to be implemented by the U.S. EPA by 2025. How to accurately predict toxicity of PFAS with varied carbon chain length is important for treatment and sequential removal from drinking water. This study presents Quantitative Structure and Activity Relationship (QSAR) models developed through both linear regression and two order regression. Log P is compiled from reference and carbon content is counted as the molecule represented. Bioconcentration potential is predicted from CompTox.The …


Pet And Polyolefin Plastics Supply Chains In Michigan: Present And Future Systems Analysis Of Environmental And Socio-Economic Impacts, Utkarsh S. Chaudhari, Kamand Sedaghatnia, Barbara K. Reck, Kate Maguire, Anne T. Johnson, David Watkins, Robert M. Handler, Tasmin Hossain, Damon S. Hartley, Vicki S. Thompson, Alejandra Peralta, Jenny L. Apriesnig, David Shonnard May 2024

Pet And Polyolefin Plastics Supply Chains In Michigan: Present And Future Systems Analysis Of Environmental And Socio-Economic Impacts, Utkarsh S. Chaudhari, Kamand Sedaghatnia, Barbara K. Reck, Kate Maguire, Anne T. Johnson, David Watkins, Robert M. Handler, Tasmin Hossain, Damon S. Hartley, Vicki S. Thompson, Alejandra Peralta, Jenny L. Apriesnig, David Shonnard

Michigan Tech Publications, Part 2

Many actions are underway at global, national, and local levels to increase plastics circularity. However, studies evaluating the environmental and socio-economic impacts of such a transition are lacking at regional levels in the United States. In this work, the existing polyethylene terephthalate and polyolefin plastics supply chains in Michigan were compared to a potential future (‘NextCycle’) scenario that looks at increasing Michigan’s overall recycling rate to 45%. Material flow analysis data was combined with environmental and socio-economic metrics to evaluate the sustainability of these supply chains for the modeled scenarios. Overall, the NextCycle scenario for these supply chains achieved a …


Advancing Simultaneous Extraction And Sequential Single-Particle Icp-Ms Analysis For Metallic Nanoparticle Mixtures In Plant Tissues, Lei Xu, Xingmao Ma, John Yang, Joel G. Burken, Paul Ki-Souk Nam, Honglan Shi, Hu Yang May 2024

Advancing Simultaneous Extraction And Sequential Single-Particle Icp-Ms Analysis For Metallic Nanoparticle Mixtures In Plant Tissues, Lei Xu, Xingmao Ma, John Yang, Joel G. Burken, Paul Ki-Souk Nam, Honglan Shi, Hu Yang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Engineered Nanoparticles (ENPs) Have Been Increasingly Used in Agricultural Operations, leading to an Urgent Need for Robust Methods to Analyze Co-Occurring ENPs in Plant Tissues. in Response, This Study Advanced the Simultaneous Extraction of Coexisting Silver, Cerium Oxide, and Copper Oxide ENPs in Lettuce Shoots and Roots using Macerozyme R-10 and Analyzed Them by Single-Particle Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Additionally, the Standard Stock Suspensions of the ENPs Were Stabilized with Citrate, and the Long-Term Stability (Up to 5 Months) Was Examined for the First Time. the Method Performance Results Displayed Satisfactory Accuracies and Precisions and Achieved Low Particle Concentration …


Lithium Extraction From Aqueous Solution Using Magnesium Doped Lithium Ion-Sieve Composite, Ujjwal Pokharel Oct 2023

Lithium Extraction From Aqueous Solution Using Magnesium Doped Lithium Ion-Sieve Composite, Ujjwal Pokharel

Civil & Environmental Engineering Theses & Dissertations

This study focused on the development of a magnesium doped ion-sieve composite to extract lithium from an aqueous solution using adsorption process. The extraction process will provide a sustainable alternative to the currently practiced solar evaporation/concentration method which is very slow (takes 24 months) and water intensive. Currently, most of the lithium in the world comes from the mining of lithium or from the evaporative extraction process from the brine. Additionally, the Salton Sea area geothermal brines are recognized as potentially important domestic sources of lithium. Lithium concentration in geothermal brines from the Salton Sea area is reported to be …


Design Of Stormwater Bmps For Surface And Groundwater Protection Based On Site-Scale Soil Properties: Phase I, Kelly Kibler, Lisa Chambers, Melanie Beazley Aug 2023

Design Of Stormwater Bmps For Surface And Groundwater Protection Based On Site-Scale Soil Properties: Phase I, Kelly Kibler, Lisa Chambers, Melanie Beazley

Florida DOT

Much of Earth’s nutrient cycling takes place in soils. Characteristics of soils control physical, chemical, and biological processes that determine rates of nutrient fluxes, storage, or transformation. As remediation of excess nutrients in stormwater runoff is one function of stormwater Best Management Practices (BMPs), the soil profile constitutes one of the most important factors of BMP design. Variation observed in BMP effectiveness (e.g., why one BMP design works effectively in one place and not another) can often be explained by variations in the soil profile, either through direct means or by a soil’s influence on hydraulics of stormwater flow through …


Fate And Transport Of Per- And Polyfluoroalkyl Substances (Pfas) At Aqueous Film Forming Foam (Afff) Discharge Sites: A Review, Jeffery T. Mcgarr, Eric G. Mbonimpa, Drew C. Mcavoy, Mohamad R. Soltanian May 2023

Fate And Transport Of Per- And Polyfluoroalkyl Substances (Pfas) At Aqueous Film Forming Foam (Afff) Discharge Sites: A Review, Jeffery T. Mcgarr, Eric G. Mbonimpa, Drew C. Mcavoy, Mohamad R. Soltanian

Faculty Publications

Per- and polyfluorinated alkyl substances (PFAS) are an environmentally persistent group of chemicals that can pose an imminent threat to human health through groundwater and surface water contamination. In this review, we evaluate the subsurface behavior of a variety of PFAS chemicals with a focus on aqueous film forming foam (AFFF) discharge sites. AFFF is the primary PFAS contamination risk at sites such as airports and military bases due to use as a fire extinguisher. Understanding the fate and transport of PFAS in the subsurface environment is a multifaceted issue. This review focuses on the role of adsorbent, adsorbate, and …


Utilization Of Cellulose Symbiotic Culture Of Bacteria And Yeast (Scoby) With Sweet Tea Media As Methylene Blue And Brilliant Green Biosorbent Material, Leonard Mateus Sigiro, Ahmad Maksum, Donanta Dhaneswara May 2023

Utilization Of Cellulose Symbiotic Culture Of Bacteria And Yeast (Scoby) With Sweet Tea Media As Methylene Blue And Brilliant Green Biosorbent Material, Leonard Mateus Sigiro, Ahmad Maksum, Donanta Dhaneswara

Journal of Materials Exploration and Findings

The cellulose from Symbiotic Culture of Bacteria and Yeast (SCOBY) can be used as a biosorbent for dye adsorption, such as Methylene Blue and Brilliant Green. This study used sweet tea with a 6% of sugar concentration and 14 days of fermentation time to synthesize biosorbent material from SCOBY. The results from this synthesis are then characterized using FTIR, SEM, and BET. From the result of characterization, it was found that SCOBY has pores formed from cellulose. The results of the average pore size are 1.5976nm with a pore volume of 0.229cc/g, while the specific surface area is 143.244m2/g. The …


Impacts Of Preferential Flow On Tc-99and Np-237 Vadose Transport In Soils At The Savannah River Site, Josh Parris May 2023

Impacts Of Preferential Flow On Tc-99and Np-237 Vadose Transport In Soils At The Savannah River Site, Josh Parris

All Theses

Since the 1950s, the United States has produced approximately 90,000 metric tons of spent nuclear fuel (SNF) (Office of Nuclear Energy, 2022); however, no long-term storage solutions are available. Technecium-99 and neptunium-237, two fission products found in SNF, readily form highly mobile species in oxidizing conditions (Hu, 2008; Bondietti, 1979) and have respective half-lives of 2.13 x 105 and 2.14 x106 years (Hu, 2010). Considering these characteristics, 99Tc and 237Np are two risk-driving isotopes found in SNF storage. The process of macropore-facilitated preferential flow, transport through cracks within a soil matrix, has been recognized to increase …


Science Club, Danielle Gibson, Krista Andersen Apr 2023

Science Club, Danielle Gibson, Krista Andersen

Honors Expanded Learning Clubs

Honors After School program for elementary age children to engage with scientific principles. Students performed hands-on experiments to explore various STEM fields. Each weekly lesson consisted of a different concept to be learned or explored by early elementary aged students.


Enzymatic Removal Of Sulfa Drugs From Synthetic Wastewater By Soybean Peroxidase, Maryam Sharifzadeh Jan 2023

Enzymatic Removal Of Sulfa Drugs From Synthetic Wastewater By Soybean Peroxidase, Maryam Sharifzadeh

Electronic Theses and Dissertations

Sulfa drugs are a broad family of antibiotics that are widely used in the treatment of a wide range of infections, and they have been found in surface and groundwater, as well as present in sewage and effluent (treated sewage and sludge)municipal or industrial wastewater treatment plants (WWTPs). in concentrations of ng/L to >g/L. The continued presence of these so-called emerging pollutants (ECs) and their metabolites can cause adverse ecological effects, including bacterial resistance, even at very low concentrations. In this study, the first aim was to explore the feasibility of oxidation processes catalyzed by soybean peroxidase as an eco-friendly …


Food Waste Storage Gaseous Emissions Detection And Quantification Using Infrared Spectroscopy, Ryley A. Burton-Tauzer Jan 2023

Food Waste Storage Gaseous Emissions Detection And Quantification Using Infrared Spectroscopy, Ryley A. Burton-Tauzer

Cal Poly Humboldt theses and projects

A growing interest in sustainable waste management and the implementation of new policies have prompted a shift towards alternative resource recovery methods for organic waste, including food waste. To effectively assess alternative food waste treatment scenarios, it is important to evaluate the life cycle impacts associated with each scenario. The storage phase of food waste, encompassing its accumulation in kitchens, and storage in bins for collection and transportation, has been overlooked as a source of greenhouse gases in previous studies. This investigation aimed to identify the greenhouse gases emitted during the initial five-day period of low-oxygen storage. An open dynamic …


Predicting The Reactivities And Reaction Mechanisms Of Photochemically Produced Reactive Intermediates, Benjamin Barrios Cerda Jan 2023

Predicting The Reactivities And Reaction Mechanisms Of Photochemically Produced Reactive Intermediates, Benjamin Barrios Cerda

Dissertations, Master's Theses and Master's Reports

Photochemically produced reactive intermediates (PPRIs) such as the hydroxyl radical, carbonate radical (CO3•-) singlet oxygen (1O2) and triplet state of chromophoric dissolved organic matter (3CDOM*) are formed in sunlit natural waters upon photoexcitation of chromophoric dissolved organic matter (CDOM). PPRIs react with the organic compounds involved in key environmental processes, resulting in transformation products of smaller molecular weight than their parent compounds. Photochemical transformation of these key water constituents due to their reactions with PPRIs may pose potential effects on human and aquatic ecosystems. Consequently, there is a need …


Reduced Metal Nanocatalysts For Selective Electrochemical Hydrogenation Of Biomass-Derived 5-(Hydroxymethyl)Furfural To 2, 5-Bis(Hydroxymethyl)Furan In Ambient Conditions, Baleeswaraiah Muchharla, Moumita Dikshit, Ujjwal Pokharel, Ravindranath Garimella, Adetayo Adedeji, Kapil Kumar, Wei Cao, Hani Elsayed-Ali, Kishor Kumar Sadasivuni, Naif Abdullah Al-Dhabi, Sandeep Kumar, Bijandra Kumar Jan 2023

Reduced Metal Nanocatalysts For Selective Electrochemical Hydrogenation Of Biomass-Derived 5-(Hydroxymethyl)Furfural To 2, 5-Bis(Hydroxymethyl)Furan In Ambient Conditions, Baleeswaraiah Muchharla, Moumita Dikshit, Ujjwal Pokharel, Ravindranath Garimella, Adetayo Adedeji, Kapil Kumar, Wei Cao, Hani Elsayed-Ali, Kishor Kumar Sadasivuni, Naif Abdullah Al-Dhabi, Sandeep Kumar, Bijandra Kumar

Chemistry & Biochemistry Faculty Publications

Selective electrochemical hydrogenation (ECH) of biomass-derived unsaturated organic molecules has enormous potential for sustainable chemical production. However, an efficient catalyst is essential to perform an ECH reaction consisting of superior product selectivity and a higher conversion rate. Here, we examined the ECH performance of reduced metal nanostructures i.e., reduced Ag (rAg) and reduced copper (rCu) prepared via electrochemical or thermal oxidation and electrochemical reduction process, respectively. Surface morphological analysis suggests formation of nanocoral and entangled nanowire structure formation for rAg and rCu catalysts. rCu exhibits slight enhancement in ECH reaction performance in comparison to the pristine Cu. However, the rAg …


Enzymatic Removal Of Diclofenac And Aceclofenac From Synthetic Wastewater By Soybean Peroxidase, Sarah Pishyar Jan 2023

Enzymatic Removal Of Diclofenac And Aceclofenac From Synthetic Wastewater By Soybean Peroxidase, Sarah Pishyar

Electronic Theses and Dissertations

Pharmaceutical medications that are a class of emerging contaminants have been detected in wastewater treatment facilities' influent and effluent, and they have reached water sources in amounts ranging from ng/L to ug/L. They threaten the environment and non-target life. Soybean peroxidase (SBP)-catalyzed process was studied to remove two non-steroidal anti-inflammatory drugs (NSAIDS) diclofenac and aceclofenac through enzymatic oxidation from synthetic wastewater. SBP can be extracted from soybean hulls, a by-product of the soybean industry. First, the experiments studied the viability of SBP-catalyzed removal on these two compounds, then the operational parameters including pH, the molar ratio between hydrogen peroxide and …


Phosphorus Release And Recovery From Simulated Ferric Wastewater Sludge, Aseel Alnimer Jan 2023

Phosphorus Release And Recovery From Simulated Ferric Wastewater Sludge, Aseel Alnimer

Theses and Dissertations (Comprehensive)

Phosphorus (P) is a fundamental element necessary for all life forms and a key component in the fertilizer industry. Meanwhile, the excessive load of P to water bodies due to human activities has the potential to promote eutrophication. Wastewater treatment plants remove P either biologically or chemically and produce P rich sludge which could be a potential renewable source for P. At present, commercial technologies exist for P recovery from biological wastewater sludge. However, P recovery from chemical sludge particularly iron(III)-phosphate (Fe-P) sludge generated in chemical P removal plants that use iron(III) salts remains a challenge.

This study explored, in …


Wastewater-Informed Public Health Intervention Playbook Sep 2022

Wastewater-Informed Public Health Intervention Playbook

Sustain Magazine

As the SARS-CoV-2 pandemic quickly spread from country to country and continent to continent in 2020, governments and scientists needed a way to track COVID-19 through populations in order to position public health interventions in the most impactful locations. Having a decision-based risk framework may help to guide policy creation that could minimize or prevent possible outbreaks and surges of infection within communities. The University of Louisville in partnership with Louisville’s Department of Public Health and Wellness tested this strategy in 2021 and 2022. This Wastewater-Informed Public Health Intervention Playbook describes the decisions and actions of that academic and public …


Application Of A 14c-Assay To Assess Methanotrophic Biodegradation Of Tce In Low Ph Groundwater, Evan Groome Aug 2022

Application Of A 14c-Assay To Assess Methanotrophic Biodegradation Of Tce In Low Ph Groundwater, Evan Groome

All Theses

Current biological strategies for remediating trichloroethylene (TCE) in low pH aquifers (i.e., pH14C-TCE assay was developed to determine pseudo first-order rate constants for the degradation of TCE in microcosms containing soil and groundwater from the Boeing Michigan Aeronautical Research Center (BOMARC) superfund site, where the pH ranges from 4.1 to 4.9. The 14C-TCE assay was also adapted to calculate soil-normalized rate constants for data from this site, as well as data that Szwast21 collected from the Beltsville Agricultural Research Center (BARC). In addition to natural attenuation, biostimulation through amendments of methane and nutrients were also assessed. This treatment …


Examining Metal Contents In Primary And Secondhand Aerosols Released By Electronic Cigarettes, Kashala Fabrice Kapiamba, Weixing Hao, Stephen Adom, Wenyan Liu, Yue-Wern Huang, Yang Wang Jun 2022

Examining Metal Contents In Primary And Secondhand Aerosols Released By Electronic Cigarettes, Kashala Fabrice Kapiamba, Weixing Hao, Stephen Adom, Wenyan Liu, Yue-Wern Huang, Yang Wang

Chemistry Faculty Research & Creative Works

The usage of electronic cigarettes (ECs) has surged since their invention two decades ago. However, to date, the health effects of EC aerosol exposure are still not well understood because of insufficient data on the chemical composition of EC aerosols and the corresponding evidence of health risks upon exposure. Herein, we quantified the metals in primary and secondhand aerosols generated by three brands of ECs. By combining aerosol filter sampling and inductively coupled plasma mass spectrometry (ICP-MS), we assessed the mass of metals as a function of EC flavoring, nicotine concentration, device power, puff duration, and aging of the devices. …


Characteristics And Assessing Biological Risks Of Airborne Bacteria In Waste Sorting Plant, Abbas Norouzian Baghani, Somayeh Golbaz, Gholamreza Ebrahimzadeh, Marcelo I. Guzman, Mahdieh Delikhoon, Mehdi Jamshidi Rastani, Abdullah Barkhordari, Ramin Nabizadeh Feb 2022

Characteristics And Assessing Biological Risks Of Airborne Bacteria In Waste Sorting Plant, Abbas Norouzian Baghani, Somayeh Golbaz, Gholamreza Ebrahimzadeh, Marcelo I. Guzman, Mahdieh Delikhoon, Mehdi Jamshidi Rastani, Abdullah Barkhordari, Ramin Nabizadeh

Chemistry Faculty Publications

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m−3) were: Staphylococcus sp. (72.4) > Micrococcus sp. (52.2) > Bacillus sp. (30.3) > Enterococcus sp. (24.0) > Serratia marcescens (20.1) > E. coli (19.1) > Pseudomonas sp. (16.0) > Nocardia …


Indoor Air Quality Through The Lens Of Outdoor Atmospheric Chemistry, Jonathan P.D. Abbatt, Douglas B. Collins Jan 2022

Indoor Air Quality Through The Lens Of Outdoor Atmospheric Chemistry, Jonathan P.D. Abbatt, Douglas B. Collins

Faculty Contributions to Books

Outdoor atmospheric chemistry and air quality have been the topic of research that intensified in earnest around the mid-20th century, while indoor air quality research has only been a key focus of chemical researchers over the last 30 years. Examining practices and approaches employed in the outdoor atmospheric chemistry research enterprise provides an additional viewpoint from which we can chart new paths to increase scientific understanding of indoor chemistry. This chapter explores our understanding of primary chemical sources, homogeneous and multiphase reactivity, gas-surface partitioning, and the coupling between the chemistry and dynamics of indoor air through the lens of …


Ozonized Biochar Filtrate Effects On The Growth Of Pseudomonas Putida And Cyanobacteria Synechococcus Elongatus Pcc 7942, Oumar Sacko, Nancy L. Engle, Timothy J. Tschaplinski, Sandeep Kumar, James Weifu Lee Jan 2022

Ozonized Biochar Filtrate Effects On The Growth Of Pseudomonas Putida And Cyanobacteria Synechococcus Elongatus Pcc 7942, Oumar Sacko, Nancy L. Engle, Timothy J. Tschaplinski, Sandeep Kumar, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

Background

Biochar ozonization was previously shown to dramatically increase its cation exchange capacity, thus improving its nutrient retention capacity. The potential soil application of ozonized biochar warrants the need for a toxicity study that investigates its effects on microorganisms.

Results

In the study presented here, we found that the filtrates collected from ozonized pine 400 biochar and ozonized rogue biochar did not have any inhibitory effects on the soil environmental bacteria Pseudomonas putida, even at high dissolved organic carbon (DOC) concentrations of 300 ppm. However, the growth of Synechococcus elongatus PCC 7942 was inhibited by the ozonized biochar filtrates at …


The Photo-Transformation Of Free Methionine In The Presence Of Surrogate And Standard Isolate Dissolved Organic Matter Under Sunlit Irradiation, Benjamin J. Mohrhardt Jan 2022

The Photo-Transformation Of Free Methionine In The Presence Of Surrogate And Standard Isolate Dissolved Organic Matter Under Sunlit Irradiation, Benjamin J. Mohrhardt

Dissertations, Master's Theses and Master's Reports

Sulfur (S)-containing amino acids are key sources of carbon, nitrogen, and sulfur involved in protein synthesis, protein function, and providing energy for microbial growth. Dissolved free and combined methionine is one of two S-containing amino acids incorporated into proteins and has been attributed to their stability and function. The oxidation of methionine has received considerable attention given its ubiquitous presence in most biological systems and has been associated with losses in protein function and pathological disorders. In natural waters, methionine is rapidly and selectively taken up by microorganisms to achieve cellular requirements of carbon, nitrogen, and sulfur. The abiotic transformation …


Identification Of Phosphorous Loading Point Source Facilities To 303(D) Listed Nutrient Impaired Waters Through Watershed Delineation Using Arcgis For Life Cycle Assessment Applications, John Zimmerman Dec 2021

Identification Of Phosphorous Loading Point Source Facilities To 303(D) Listed Nutrient Impaired Waters Through Watershed Delineation Using Arcgis For Life Cycle Assessment Applications, John Zimmerman

Chemical Engineering Undergraduate Honors Theses

The work done for this project is part of a larger “life cycle assessment (LCA) of novel electrochemical phosphorus recovery technology at the wastewater treatment plant and U.S. watershed scales” (Morrissey 2019). The goal of that LCA is to determine “environmental impacts of implementing electrochemical struvite recovery at the wastewater treatment plant, U.S watershed, and global scales” (Morrissey 2019). This project’s goal is to identify locations deemed more sensitive to eutrophication impacts. The results will be used as part of the life cycle inventory (LCI) accounting for geographically explicit phosphorus flows. The waters identified as impaired were sourced from the …


Formation Of Reactive Nitrogen Species During Dichloramine Decay And Their Impact On N Nitrosodimethylamine Formation Under Drinking Water Conditions, Huong Thu Pham Dec 2021

Formation Of Reactive Nitrogen Species During Dichloramine Decay And Their Impact On N Nitrosodimethylamine Formation Under Drinking Water Conditions, Huong Thu Pham

Graduate Theses and Dissertations

NDMA occurrence and formation pathways in drinking water systems are reviewed and NDMA yields are compared on the basis of disinfectant type, water chemistry, and precursor category. In chloramination, despite monochloramine being the predominant species between pH 7-9, evidence suggests that dichloramine is the primary species involved in NDMA formation. This is somewhat confounding as NDMA yields are maximal at pH 9, yet at pH 9 dichloramine decays faster than it forms and hence is present at trace levels; additionally, the proposed mechanism involves a spin-forbidden incorporation of dissolved oxygen as a triplet, which is presumably kinetically slow. This review …


Effects Of Nitrate On Arsenic Mobilization During Aquifer Storage And Recovery, Hania Hawasli Oct 2021

Effects Of Nitrate On Arsenic Mobilization During Aquifer Storage And Recovery, Hania Hawasli

USF Tampa Graduate Theses and Dissertations

Aquifer storage and recovery technology is used to sustain water resources and to prevent saltwater intrusion. The injected water can come from various resources, including treated wastewater. In pilot ASR studies in the Tampa Bay region, researchers found high As concentrations in the recovered water from the oxidation of the arsenopyrite that is embedded in the aquifers. The presence of dissolved O2 in the injected water is a major factor in the arsenopyrite oxidation during ASR, however the effects of NO3- on the arsenopyrite has not been studied yet. This is an important knowledge gap because injected water may contain …


Chitosan Graphene Composite Fabrication And Characterization For Treatment Of Harmful Algal Blooms And Toxins, Sarah Zetterholm Oct 2021

Chitosan Graphene Composite Fabrication And Characterization For Treatment Of Harmful Algal Blooms And Toxins, Sarah Zetterholm

Master's Theses

Chitosan graphene composites were fabricated and characterized as a management strategy for harmful algal blooms (HABs) caused by various species of cyanobacteria. These chitosan graphene materials were compared to previously studied chitosan graphene-oxide composites in both material properties and HAB treatment. In previous studies, adsorption of the cyanobacteria onto the surface of the composite materials has been observed. Investigations of the pure materials for these composites are also included in this study to determine whether removal is a result of charge interactions with the composite, or as an inherent property of the graphene or graphene oxide. Initial results suggest that …


Unintended Consequences Of Air Cleaning Chemistry, Douglas B. Collins, Delphine K. Farmer Aug 2021

Unintended Consequences Of Air Cleaning Chemistry, Douglas B. Collins, Delphine K. Farmer

Faculty Journal Articles

Amplified interest in maintaining clean indoor air associated with the airborne transmission risks of SARS-CoV-2 have led to an expansion in the market for commercially available air cleaning systems. While the optimal way to mitigate indoor air pollutants or contaminants is to control (remove) the source, air cleaners are a tool for use when absolute source control is not possible. Interventions for indoor air quality management include physical removal of pollutants through ventilation or collection on filters and sorbent materials, along with chemically reactive processes that transform pollutants or seek to deactivate biological entities. This perspective intends to highlight the …


Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown Aug 2021

Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown

Masters Theses

A substantial societal shift towards environmental awareness has focused research efforts on the impacts of pollution on natural landscapes. Improvements to pollutant regulations and technology have resulted in sizeable reductions of atmospheric deposition of anthropogenic acids, especially nitrates and sulfates, which has altered the role of these ions in the environment. As such, understandings of environmental chemistry dynamics have required regular updating.

Through the National Park Service Vital Signs monitoring program, increases in precipitation pH observed in Great Smoky Mountains National Park (GRSM) has been attributed to the reduction of inorganic acid concentrations. Unfortunately, these improvements have not been uniformly …


Post Covid-19 Water And Waste Water Management To Protect Public Health And Geoenvironment, Ken Cornell, Arvin Farid May 2021

Post Covid-19 Water And Waste Water Management To Protect Public Health And Geoenvironment, Ken Cornell, Arvin Farid

Chemistry and Biochemistry Faculty Publications and Presentations

The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. The findings of severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) traces in waste water and the practice of disinfecting outdoor spaces in several cities in the world, which can result into the entry of disinfectants and their by-products into storm drainage systems and their subsequent discharge into rivers and coastal waters, raise the issue of environmental, ecological and public health effects. The aims of the current paper are to investigate the potential of water and waste water to operate as transmission routes for Sars-CoV-2 and the …