Chemistry Commons^™

Significance Of Hno3 Acid Photolysis On Surfaces In Tropospheric Chemistry, Honglian Gao

Legacy Theses & Dissertations (2009 - 2024)

The reactive nitrogen trace gases (NO_y) including nitrogen oxides (NO_x) and their secondary products are known to cause ground-level ozone pollution, photochemical smog, acid deposition, and overall air quality degradation. NO_x was believed to be permanently removed from the atmospheric by HNO₃ formation and deposition. However, our laboratory experimental results show that HNO₃ can be remobilized back to photochemically labile HONO and NO_x (re-NOx-ification). We have verified and quantified HONO and NO_x production from the photolysis of HNO₃ on various surfaces, including Pyrex, leaves of plants, and other environmentally relevant …

Interactions Of Hydrogen Peroxide And Oxalic Acid On Ice Films, Hui Yan

Legacy Theses & Dissertations (2009 - 2024)

The heterogeneous halogen chemistry plays a critical role in the ozone depletion events in the polar boundary layers. Pathways involving the conversion from photochemically active halogens to photochemically inactive halogens are necessary to understand the nature of ozone depletion, but the processes are not fully understood. The study of the effects of hydrogen peroxide (H₂O₂) and oxalic acid (C₂H₂

Accumulation, Speciation, And Distribution Of Metal(Loids) In Plants: Applications Of Synchrotron Techniques In Environmental Sciences, Hiram Castillo-Michel

Open Access Theses & Dissertations

In the last two decades, synchrotron based techniques have gained popularity and been increasingly used in environmental sciences. The present dissertation has relied significantly in the use of synchrotron based techniques to study the speciation, coordination, and distribution of toxic metal(loids) in plants. This study included three plant species: Parkinsonia florida, Prosopis juliflora, and Zea mays. P. florida is a plant species native to the semi-desert regions of North America. The cultivation characteristics of this shrub/tree suggest that it could be used for phytoremediation purposes in semiarid regions. P. florida plants were tested for their capacity to remove arsenic (As) …

Fossil And Contemporary Aerosol Particulate Organic Carbon In The Eastern United States: Implications For Deposition And Inputs To Watersheds, Andrew S. Wozniak, James E. Bauer, Rebecca M. Dickhut

Chemistry & Biochemistry Faculty Publications

Atmospheric particulate matter samples were collected from mid-Atlantic and northeastern U. S. (Virginia and New York, respectively) sites to assess the fossil versus contemporary sources contributing to aerosol organic carbon (OC) and the implications for its deposition to watersheds. Mean particulate matter total OC (TOC) deposition rates (wet + dry deposition) were calculated to be 1.6 and 2.4 mg C m^-2 d^-1 for the Virginia and New York sites, respectively. Wet deposition of particulate TOC was determined to be the dominant depositional mode, accounting for >65% (Virginia) and >80% (New York) of total aerosol TOC deposition. Isotopic mass …

Quality Of Wastewater In The El Paso, Texas Region--Analysis Of Pharmaceuticals And Personal Care Products Using High Performance Liquid Chromatography Tandem Mass Spectrometry, Rodolfo Guerrero Jr.

Open Access Theses & Dissertations

Pharmaceuticals and Personal Care Products (PPCPs), such as household cleaning materials, prescription medication, and personal hygiene products, are pollutants of emerging concern that are found in 80% of our water system. Because of their applications, PPCPs are subsequently being released into wastewater; however, current wastewater treatment facilities are not regulated or designed to remove PPCPs. Therefore, these compounds are discharged into the environment on a continual basis. The effects of PPCPs on human health are not yet well known; however, recent research has found that exposure to these chemicals has some adverse developmental effects on aquatic species at low concentrations …

A Practical Photoelectrochemical Cell Using Nonprecious Metal Electrodes, Patrick Enright, Tony Betts, John Cassidy

Articles

Abstract: Photoelectrochemical cells (PECs) can be used to harvest light from the oxidation of dissolved organic matter. Similar to fuel cells but requiring light to operate, PECs contain a light assisted electrode that oxidises electron rich materials (anode); these electrons then flow to a typically Pt cathode where O₂ is normally the electron acceptor. In this work a PEC cell containing inexpensive materials was shown to (a) mineralise typical organic compounds present in waste water and (b) produce electricity from their decomposition. The PEC cell consisted of a TiO₂ coated conducting ink anode exposed to a light source, …

The Vinylguaiacol/Indole Or Vgi ("Veggie") Ratio: A Novel Molecular Parameter To Evaluate The Relative Contributions Of Terrestrial And Aquatic Organic Matter To Sediments., Michael A. Kruge, Kevin K. Olsen, Jaroslaw W. Slusarczyk, Elaine Gomez

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The organic matter (OM) fraction of estuarine sediments is often distinctive and thus diagnostically useful in determinations of sedimentary provenance. Among the most fundamental distinctions to be made is that between terrestrial and aquatic OM. To supplement the parameters commonly used for this purpose (e.g., C/N and stable isotope ratios), we proposed the Vinylguaiacol/Indole or VGI ("Veggie") ratio, defined as [vinylguaiacol / (indole + vinylguaiacol)] using data produced by analytical pyrolysis-gas chromatography/mass spectrometry of dried, homogenized sediment samples. The ratio employs the peak areas of these two compounds on the mass chromatograms of their molecular ions (m/z 150 and 117). …

Isotherms And Kinetics Studies Of Lead Adsorption On Jatropha Seed Husk., Faheem Ahmed Qaid Mohammed

Student Works (2010-2019)

Presence of lead, a heavy metal in the environment has been a serious concern especially with rapid industrialization which has created new uses for lead. The acute toxicity of lead to aquatic Life and humans and the stringent effluent standard to be met by industries as specified by regulatory organizations has necessitated the development of innovative, effective and economical methods for treating lead-bearing wastewater. An adsorption process using an inexpensive adsorbent such as Jatropha seed husk is an attractive option for the removal of lead from wastewater. In this study batch isotherm and kinetic studies were carried out on a …

Extensive Aerosol Optical Properties And Aerosol Mass Related Measurements During Tramp/Texaqs 2006 – Implications For Pm Compliance And Planning, Monica Elizabeth Wright, Dean B. Atkinson, Luke Ziemba, Robert Griffin, Naruki Hiranuma, Sarah D. Brooks, James Flynn, Ryan Perna, Bernhard Rappenglück, Winston Luke, Paul Kelley

Chemistry Faculty Publications and Presentations

Extensive aerosol optical properties, particle size distributions, and Aerodyne quadrupole aerosol mass spectrometer measurements collected during TRAMP/TexAQS 2006 were examined in light of collocated meteorological and chemical measurements. Much of the evident variability in the observed aerosol-related air quality is due to changing synoptic meteorological situations that direct emissions from various sources to the TRAMP site near the center of the Houston-Galveston-Brazoria (HGB) metropolitan area. In this study, five distinct long-term periods have been identified. During each of these periods, observed aerosol properties have implications that are of interest to environmental quality management agencies. During three of the periods, long …

Hrc Enews — 2010 Fall, Megan K. Svarz

Publications (HRC)

This issue contains staff accomplishments and announcements, event listings, and a "new faces" listing for new staff, affiliates, and researchers.

Site-Specific Photocatalytic Splitting Of Methanol On Tio2(110), Chuanyao Zhou, Zefeng Ren, Shijing Tan, Zhibo Ma, Xinchun Mao, Dongxu Dai, Hongjun Fan, Xueming Yang, Jerry L. Larue, Russell Cooper, Alec M. Wodtke, Zhou Wang, Zhenyu Li, Bing Wang, Jinlong Yang, Jianguo Hou

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Clean hydrogen production is highly desirable for future energy needs, making the understanding of molecular-level phenomena underlying photocatalytic hydrogen production both fundamentally and practically important. Water splitting on pure TiO₂ is inefficient, however, adding sacrificial methanol could significantly enhance the photocatalyzed H₂ production. Therefore, understanding the photochemistry of methanol on TiO₂ at the molecular level could provide important insights to its photocatalytic activity. Here, we report the first clear evidence of photocatalyzed splitting of methanol on TiO₂ derived from time-dependent two-photon photoemission (TD-2PPE) results in combination with scanning tunneling microscopy (STM). STM tip induced molecular manipulation …

Nvrec Subtask 1.1: Pre-Treatment Of Lignocellulosic Biomass, Amber Broch, Kent Hoekman, Larry Felix, Rick Purcell, Curt Robbins, Wei Yan

Nevada Renewable Energy Consortium Meeting

The second annual Nevada Renewable Energy Consortium meeting took place at UNLV on August 20. The meeting focused on the current three NVREC program areas: Solar, Biomass and Geothermal. Presentations were made by participating entities and a poster session followed.

Nvrec Subtask 1.2: Thermal Treatment Of Biomass, Curtis Robbins, Eric Ceniceros, Kent Hoekman, Richard Jasoni

Nevada Renewable Energy Consortium Meeting

The second annual Nevada Renewable Energy Consortium meeting took place at UNLV on August 20. The meeting focused on the current three NVREC program areas: Solar, Biomass and Geothermal. Presentations were made by participating entities and a poster session followed.

Nitrogen Cycle In Great Basin Hot Springs, Tara A. Edwards, Paula Matheus-Carnevali, Ryan Wahrenbrock, Jeremy A. Dodsworth, Brain P. Hedlund

Undergraduate Research Opportunities Program (UROP)

Nitrification and denitrification are two important steps in the nitrogen cycle . Nitrification, a two step process, leads to the production of NO3-, (Fig. 1). In the first step, ammonia oxidation, NH3 is oxidized to NO2-, and in the second step, nitrite oxidation, NO2- is oxidized to NO3-. Until recently, very little was know about nitrification in high temperature environments. However, in 2008 a thermophilic archaeon, named “Candidatus Nitrosocaldus yellowstonii”, was shown to mediate ammonia oxidation up to 74°C. More recently , NO2- oxidizing bacteria were discovered that are active in temperatures up to 48°C(4). While NH3 oxidation is generally …

Oxygen Isotopes As A Tracer Of Dom Processes In River-Estuary Systems, Joy Ashley Matthews

OES Theses and Dissertations

In the biogeochemical study of dissolved organic matter (DOM) in natural waters, stable isotopes are used to provide insight into both the sources of DOM and the processes affecting its alteration. Through the research presented here, oxygen isotopes are incorporated into the study of DOM through the adaptation of a pyrolysis elemental analysis isotope ratio mass spectrometer method, and sample preparation using two-stage ultrafiltration.

The application of oxygen isotopes to the study of DOM is demonstrated in two studies. First, natural abundance of δ¹⁸O in DOM is explored in the Delaware estuary. Using a two end-member mixing model, …

Hrc Enews — 2010 Summer, Megan K. Svarz

Publications (HRC)

This issue contains staff accomplishments and announcements, event listings, and a "new faces" listing for new staff, affiliates, and researchers.

Degradation Of Chlorophenols In Swine Waste, Srilatha Gangula

Masters Theses & Specialist Projects

Naturally occurring plant derived phenols can be degraded through bacteria in swine waste. Chlorinated phenols, which are not naturally present in the environment, are toxic and generated from industrial activities as such petrochemical, pharmaceutical, plastic, rubber, pesticide, iron, steel, paper production, coal conversion, wood preserving, and cellulose bleaching. Large scale coal gasification and carbonization plants are another source of chlorinated phenols. Although not normally present in the environment, chlorinated phenols are structurally similar to many plant derived phenolics.

It is our hypothesis that bacteria located in swine wastes may also have the ability to degrade chlorinated phenols. Identifying situations (and …

Trace Analysis Of Volatile Organic Compounds In The Water Of The Arroyo Colorado And The Lower Laguna Madre Utilizing E.P.A.Sw846 Method 8260, Humberto Valdez

Theses and Dissertations - UTB/UTPA

Volatile organic compounds (VOC) can cause a major environmental concern since they create a hazard to public health and the environment. This study focused on determining concentration of VOCs in Arroyo Colorado waters and the Lower Laguna Madre (LLM) utilizing GC/MS. Little is known on the concentration and composition of VOCs. Toluene was the most common VOC. Concentrations ranged from 0.0010 mg/L to 0.0039 mg/L. Analysis of a sediment pore water sample collected near the mouth of the Arroyo Colorado also detected toluene (0.0023 mg/L). This study showed that VOCs were concentrated near the county boat launch and somewhat downstream. …

Characterization Of Plutonium Particles Originating From The Bomarc Accident -1960, Richard Charles Gostic

UNLV Theses, Dissertations, Professional Papers, and Capstones

Within the U.S. arsenal, 32 accidents with nuclear weapons were reported between 1950 and 1980. One of these accidents occurred at McGuire AFB in 1960. A BOMARC missile armed with a nuclear warhead caught on fire and as a result the warhead was destroyed. Sub-millimeter particles consisting of weapons grade plutonium (WGPu) produced by this accident were distributed around the site and remained in the environment for 47 years. Soil cores known to contain WGPu particles produced by this accident were obtained. The particles were localized and removed from the soil with the aid of high resolution computed tomography. The …

Environmental Analysis Of Toxic Metals Produced By Cigarette Smoking, Catherine H. Swandby, Melissa C. Rhoten, Joseph E. Garcia

Theses & Honors Papers

Trace metal elements introduced into our environment from anthropogenic sources can become toxic at high levels contributing to a host of human and animal health problems. The purpose of this work is to initially characterize toxic metals present in cigarette tobacco and ash using Electrothermal Atomic Absorption Spectroscopy (ETAAS). The broader impact of this study is to assess the environmental effects of cigarette smoking around designated smoking areas on the Longwood University campus. Smokers may not be informed about the potential harm to the environment from "ashing" directly on the ground. If the toxic metals present in cigarette ash are …

Adaptivearc And The Future Of The Energy Industry, Trevor Chase

Earth and Soil Sciences

No abstract provided.

Hrc Enews — 2010 Spring, Megan K. Svarz

Publications (HRC)

This issue contains staff accomplishments and announcements, event listings, a "new faces" listing for new staff, affiliates, and researchers, and an "of interest" section.

Volume 03, Cheryl Peck, Charles Hoever, Longwood Theater Department, Brittany Anderson, J. Ervin Sheldon, Richard Hayden, Yuri Calustro, Candice Fleming, Rebecca Franklin, Ashley Yocum, Danielle M. Jagoda, Cristina M. Valdivieso, Jameka Jones, Amy Ellis, Ashley Maser, Erikk Shupp, Jamie Yurasits, Joshua Davis, Alexander Leonhart, Kenny Wolfe, Sally Meadows, J. Haley, Amy Jackson, Morgan Howard, Adrienne Heinbaugh, Melissa Dorton, Ciarra Stalker

Incite: The Journal of Undergraduate Scholarship

Introduction from Dean Dr. Charles Ross

Little Shop of Horrors by Longwood Theater Department

Who Has the Hottest Hotsauce in Farmville: A Quantitative Comparison of Sauces from Local Restaurants by Cheryl Peck and Charles Hoever

Precipitation Effects on the Growth of White Oaks and Virginia Pines on the Mt. Vernon Plantation by Brittany Anderson

Design and Synthesis of Novel Ion Binding Molecules for Self-Assembly and Sensing Applications by J. Ervin Sheldon

A Statistical Analysis of Algorithms for Playing SameGame by Richard Hayden

Intersecting Cylinders at Arbitrary Angles by Yuri Calustro

Putting a Foot in the Revolving Door: Strategies for Reducing …

Relatin Dissolved Oxygen Concentration To Fish Distribution In Jarecki Lake, Adam Sutton

Department of Environmental Studies: Undergraduate Student Theses

Abstract Water temperature and dissolved oxygen (DO) profiles were measured once every month from mid July to mid February in a relatively deep sand-pit lake in southeast Nebraska. These profiles showed depleted DO concentrations below the thermocline during summer stratification indicating areas fish will likely avoid in summer months. Colder temperatures in fall caused complete mixing of the water column allowing fish to inhabit all depths of the lake. An inverse temperature stratification occurred directly below the ice during winter months as ice cover cooled the surface water to below 4 degrees Celsius. Ice cover also blocked air – water …

Herbicides And Amphibian Populations, Zach Shirk

Department of Environmental Studies: Undergraduate Student Theses

Amphibians are a unique class of species that are found worldwide except Antarctica and Greenland. They range in size from a few millimeters to over six feet long. Amphibian’s habitats are as various as their size, but one thing in common is that amphibians require an aquatic location to breed. Amphibians live in deserts, mountain prairies, rain forest, wetlands, and almost everywhere in between. Amphibians are an integrated part of most natural ecosystems across the world. Amphibians are a critical part of many food chains; they provide the important link between secondary and tertiary consumers. Amphibians are indicator species in …

Physical And Biochemical Assessment Of Mexican Palo Verde Response To Chromium Toxicity, Yong Zhao

Open Access Theses & Dissertations

In the United States, about 1/3 of the 1400 superfund sites have been reported to be chromium contaminated, making chromium the second most common metal found in superfund chemical contamination sites. Chromium removal from soil has commonly been carried out via chemical, physical, and thermal processes. However, these methods are expensive and/or invasive to local ecosystems. In contrast to these techniques, phytoremediation (the use of plants to remove toxic substances from areas containing contamination at low or medium levels) appears to be a cost-effective and environmentally friendly process for chromium removal. However, most reports on chromium phytoremediation suggest that this …

Geochemical Investigation Of An Offshore Sewage Sludge Deposit, Barcelona, Catalonia, Spain, Michael A. Kruge, Albert Permanyer, Jordi Serra, Danlin Yu

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

For 20 years ending in the 1990’s the city of Barcelona discharged the products from a large primary sewage treatment plant directly into the Mediterranean Sea via underwater conduits. About ca. 3 million m³ of relict sewage sludge, rich in organic matter and heavy metals, has spread over an elongated area offshore, due to successive ruptures of the conduits. The use of the discharge pipes ceased, but he sludge deposit remains in place for the time being.

To understand the history and present state of the sludge deposit in advance of future remediation, a program of geophysical mapping, sampling, …

Titanium Niobium Nano Porous Materials: New Photocatalysts For Water Decontamination, Maryam Zarei Chaleshtori

Open Access Theses & Dissertations

Water pollution is major environmental problem worldwide. Many common industrial organic compounds that make their way into water systems can be carcinogenic at trace levels and are difficult and costly to remove completely with conventional technologies. Because of this, authorities and researchers are trying to improve current water cleanup techniques.

Heterogeneous photocatalysts that accelerate the photocatalytic destruction of organic contaminants in water are a potentially inexpensive and highly effective way to remove both trace-level and saturated harmful compounds from industrial waste streams and drinking water. Titanium dioxide has the potential to completely mineralize organic compounds in water under ultraviolet light. …

Comparison Of In Situ And Columnar Aerosol Spectral Measurements During Texaqs-Gomaccs 2006: Testing Parameterizations For Estimating Aerosol Fine Mode Properties, Dean B. Atkinson, Paola Massoli, Norman T. O'Neill, Patricia K. Quinn, Sarah D. Brooks, Barry Lefer

Chemistry Faculty Publications and Presentations

During the 2006 Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS 2006), the optical, chemical and microphysical properties of atmospheric aerosols were measured on multiple mobile platforms and at ground based stations. In situ measurements of the aerosol light extinction coefficient (σep) were performed by two multi-wavelength cavity ring-down (CRD) instruments, one located on board the NOAA R/V Ronald H. Brown (RHB) and the other located at the University of Houston, Moody Tower (UHMT). An AERONET sunphotometer was also located at the UHMT to measure the columnar aerosol optical depth (AOD). The σep data …

Optimization Of Solid-Phase Microextraction For The Determination Of Organo-Phosphorus And Organo-Chlorine Pesticide Residues In Natural Water Near Aquaculture Farms., Chan Chun Foong

Student Works (2010-2019)

The global shrimp farming industry had a rapid growth in the 1980s due to the high demand for shrimp. Apart from the destruction of mangroves and wetlands, the intensive operation of shrimp aquaculture deteriorated the water quality in the region. Variety of chemicals and biological products were used to prevent the outbreaks of diseases in the intensively managed shrimp ponds. Pesticides were used as disinfectands to kill unwanted organisms in the pond. SPME-GC-ECD method was developed for the determination of azinphos-ethyl, chlorphyrifos-methyl, diazinon, dichlorvos, endosulfan-I, endosulfan-II, endosulfan sulfate and malathion from water samples of shrimp aquaculture area in Manjung district, …