Physical Sciences and Mathematics Commons^™

The Interaction Of Different Primary Producers And Physical And Chemical Dynamics Of An Urban Shallow Lake, Majid Sahin

Dissertations, Theses, and Capstone Projects

An artificial urban shallow lake, Prospect Park Lake (PPL), is situated on a terminal moraine in Brooklyn New York, and supplied with municipal water treated with ortho-phosphates. The constant input of the phosphate nutrient is the primary source of eutrophication in the lake. The numerous pools along the water course houses various aquatic phototrophs, which influence the water quality and the state of the system, driving conditions into favoring the survival of their species. In the first half of the dissertation, the focus of the project is on analyzing how the different primary producers in different regions of PPL affect …

A Comparison Of Methods Used For The Elimination Of Organics From Soil Prior To Analysis By Ftir-Atr And Sem-Eds, Argeliz Pomales

Student Theses

This project suggests improvements to the treatment methods utilized for the sample preparation and evaluation of minerals in soil samples encountered in forensic science casework and research. The evaluation of pre-treated and post-treated soil samples were performed using Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR) and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). Because soil samples contain a significant amount of organic matter and water which interfere with examination of these minerals while using these instruments, pretreatment methods are necessary to isolate the mineral fraction for examination and analysis.

Soil samples were first sieved with various size stainless steel mesh …

Investigating The Mechanisms Driving Mercury Reduction And Emissions In Soil, Hamil Patel

Student Theses

The water-induced emission of mercury from soil has been studied, but a complete understanding of the mechanisms driving mercury reduction and emission in soil has not been reached. The current understanding is an immediate expulsion of soil gaseous mercury upon water treatment and an upward transport of dissolved soil ionic mercury as the water evaporates. We analyzed emissions from several types of samples using various methods to further our understanding on the mechanisms involved. Light-induced emissions from aqueous samples of humic acid (HA) spiked with mercury (II) chloride (HgCl₂) showed that at higher concentrations of HA, less mercury …

Development Of An Lcms Analytical Method With Applicability To Determination Of Trace Level Explosives In Environmental Waters, Cristina I. Veresmortean

Dissertations, Theses, and Capstone Projects

Traces of explosives and their degradation products present in explosives contaminated sites from military sources, such as training facilities, impose a great concern over the public health and our eco-system. This work is centered around finding an efficient way to extraction of these chemicals from water samples and their analysis using advanced separation technology: LC-MS/MS Shimadzu Prominence 8050 and AB Sciex Trap 4000 LC-MS/MS. Different extraction methods will be proposed, along with chromatographic and mass spectroscopy method development. Dependent on the target analyte polarity, thermal degradation, solubility and type of matrix, an appropriate method of analysis will be established. The …

Potential Degradation Of Hexabromocyclododecane (Hbcdd) In Sediments: Stereoisomer Specific Reaction Of Hbcdd With Reduced Sulfur Species Or Fe(Ii) Bound To Iron Oxides, Xianmiao Zhang

Dissertations, Theses, and Capstone Projects

The individual degradation rates of the three dominant stereoisomers (alpha, beta, gamma) of hexabromocyclododecane (HBCDD) with bisulfide and polysulfides were investigated at pH 9-10 in methanol/water solutions at two different temperatures (25 °C and 40 °C). alpha-HBCDD reacts significantly slower than beta-HBCDD and gamma-HBCDD. It was also observed that the reaction of HBCDD with polysulfides is faster than with bisulfide. For the reaction of HBCDD with bisulfide, the experiments were performed in 20% water/80% methanol, 50% water/50% methanol and 80% water/20% methanol at 40 °C. It was determined that the solvent polarity affects the reaction and the second-order rate constants …

Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li

Dissertations, Theses, and Capstone Projects

For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO₂ electrochemical reduction reaction (CO₂ERR). The Faradaic efficiencies (FE) of CO and CH₄ formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH₄ formation of 29% and 0.76%, respectively. It was found that the overall performance in CO₂ERR dramatically increased upon the reduction pretreatment of the carbons in N₂-saturated electrolyte before the CO₂ reduction process. The pretreated carbon showed the maximum FE of CO …

Organic Photochemistry: Remote Delivery Of Reactive Oxygen Intermediates Via A Heterogeneous Approach, Niluksha Walalawela Abeykoon

Dissertations, Theses, and Capstone Projects

Photosensitized oxidation reactions produce a number of intermediates species, which are generated in varying amounts over time. This complexity presents major challenges in the study of oxidation processes. Mechanistic efforts to separate and deliver reactive oxygen intermediates enable their controlled use in processes such as bacterial inactivation. This thesis describes a heterogeneous reaction approach taken to control the generation and delivery of reactive oxygen intermediates. The mechanistic details of photosensitized reactions were elucidated via synthetic, materials, and physical organic techniques to optimize the delivery of reactive oxygen intermediates. This thesis contains six chapters as described below.

Chapter 1 gives a …

The Study Of The Degradation Of Hexabromocyclododecane In A Heterogeneous System Containing Fe(Ii) Adsorbed To The Iron Oxide Hematite., Kristian K. Roopnarine

Dissertations and Theses

The reaction of hexabromocyclododecane (HBCDD), a widely used brominated flame retardant, was studied in a heterogenous mixture containing reactive Fe(II) adsorbed to the iron oxide hematite. The adsorbed Fe(II)/iron oxide system has shown to be a potent reductant in the transformation of organic contaminants with relatively water soluble organic contaminants. There currently aren’t many studies involving hydrophobic organic contaminants, such as HBCDD, in this reducing Fe(II)/iron oxide system. The results indicate that across the pHs 6.86, 6.95, 7.15 and 7.35 γ and β-HBCDD are degraded within a couple days. The pseudo-first order rate constants at pH 6.95 are 0.049 hr …

Toxic Gas Sensing On Nanoporous Carbons, Nikolina-Eleni Travlou

Dissertations, Theses, and Capstone Projects

Activated carbons, either synthetic, developed in our laboratory, or commercial, were prepared or further modified, in order to introduce specific heteroatoms such as oxygen, nitrogen and sulfur to their matrices. Chips coated with thin layers of the carbon samples were used for the sensing of gaseous ammonia. They were exposed to continuous cycles of various ammonia concentrations (10-500 ppm), and changes in normalized resistance were analyzed. In all cases linear responses were recorded and the chips reached sensitivities as high as 31%, which are comparable to those of modified graphene-based sensors. The applied specific surface chemical modifications were an effective …

Synthesis Of Complex/Multifunctional Metal (Hydr)Oxide/Graphite Oxide/Aunps Or Agnps Adsorbents And Analysis Of Their Interactions With Chemical Warfare Agents, Dimitrios A. Giannakoudakis

Dissertations, Theses, and Capstone Projects

One of the most widely used chemical warfare agent (CWA) is mustard gas, which is a highly toxic blistering agent. In this study we investigated the interactions of mustard gas surrogates’ vapors on zinc and zirconium hydroxides and their composites with graphite oxide (GO) and/or Au or Ag nanoparticles. Even though a small quantity of reports about the detoxification of CWAs on metal oxides is reported in the literature, almost all of these studies are performed in the liquid phase. Both herein reported Zn(OH)₂ and Zr(OH)₄ showed a good adsorption performance, with the former being photoactive under visible …

Adsorption Of Antibiotics By Vermiculite, Mosa J. Ferdous

Dissertations and Theses

The occurrence of residual antibiotics in the environment has been a worldwide issue and warrants the development of inexpensive yet effective methods for antibiotics removal from contaminated water. In this thesis work, the adsorption of four antibiotics, namely chlorotetracycline (CTC), oxytetracycline (OTC), ofloxacin (OFL), and enrofloxacin (ENR), onto natural vermiculite has been studied using batch (static) and column (dynamic) adsorption techniques. The Langmuir and Freundlich isotherm models were initially used to explain the adsorption processes. The separation factor (RL) values derived from the Langmuir model and the 1/n values derived from Freundlich model in the present investigation were less than …

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.