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Daphney, Cedrick M. "The Fate and Transport of Chemical Warfare Agent Simulants in Complex Matrices." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_theses/13.
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Experiments to determine the fate and transport of the chemical warfare agent (CWA) simulants diisopropyl fluorophosphate (DIFP), O,S-diethyl methylphosphonothioate (OSDEMP), and 2-Chloroethyl ethyl sulfide (CEES) exposed to complex matrix systems are reported here. The aforementioned simulants were used in place of O-isopropyl methylphosphonofluoridate (GB), O-Ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX), and Bis (2-chloroethyl) sulfide (HD), respectively. At ambient temperature, simulant pH (2.63 to 12.01) and reaction time (1 minute to 24 hours) were found to have significant influence on the recovery of simulants from charcoal, plastic, and TAP (butyl rubber gloves) in aqueous media. Buffer systems used included, phosphate, acetate, borate, and disodium tetraborate. Organic extractions were carried out using a 90:10 (v/v) dichloromethane / 2-propanol solution. All extracts were analyzed with a gas chromatograph equipped with flame ionization and flame photometric detectors (GC-FID-FPD). The FPD was used to determine the amount of simulant recovery.
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Gordon, Wesley Odell. "Metal Oxide Nanoparticles: Optical Properties and Interaction with Chemical Warfare Agent Simulants." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29634.
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Materials with length scales in the nanometer regime demonstrate properties that are remarkably different from analogous bulk matter. As a result, researchers are striving to catalog the changes in properties that occur with decreasing size, and more importantly, understand the reason behind novel nanomaterial properties. By learning the true nature of nanomaterials, scientists and engineers can design better materials for a variety of applications. Inert gas-phase condensation synthesis of metal oxide nanoparticles was used to develop materials to explore the optical and chemical properties of metal oxide nanoparticles.
One potential application for nanomaterials is use in optical applications. The possibility of interparticle energy transfer was investigated for lanthanide-doped yttrium oxide nanoparticles using laser spectroscopy. Experimental evidence collected with this study indicates that interparticle, lanthanide-mediated energy transfer may have been observed. In addition, lanthanide-doped gadolinium oxide nanoparticles were synthesized and investigated with optical spectroscopy to identify the best potential candidates for bioanalytical applications of this material. The influence of particle annealing and dopant concentration were also studied.
Nanoparticle film structure was investigated with scanning electron microscopy. Two different film structures composed of oxide nanoparticles were found to grow under different synthesis conditions. The film structure was found to be determined by the degree of particle aggregation in the gas phase during synthesis. Aggregation of the particles was found to be controlled by a combination of gas pressure and properties.
Chemical properties of metal oxide nanoparticles also are very important. Reflection-absorption Infrared Spectroscopy and vacuum surface analytical techniques were used to explore the chemistry of the chemical warfare agent dimethyl methylphosphonate (DMMP) on yttrium oxide as well as other metal oxide nanoparticles. DMMP was found to dissociate at room temperature on several types of metal oxide nanoparticles. Hydroxyl groups were found to be critical for the adsorption of DMMP onto the particles. Finally, the reactivity of the nanoparticles was found to increase with decreasing particle size. This was attributed to a relative increase in the number of high-energy surface defects for the smaller particles.Ph. D.
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McPherson, Melinda Kay. "The Reactivity of Chemical Warfare Agent Simulants on Carbamate Functionalized Monolayers and Ordered Silsesquioxane Films." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26793.
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The reactivity of chemical warfare agents (CWAs) and CWA simulants on organic and oxide surfaces is not currently well understood, but is of substantial importance to the development of effective sensors, filters and sorbent materials. Polyurethane coatings are used by the armed forces as chemical agent resistive paints to limit the uptake of CWAs on surfaces, while the use of metal oxides has been explored for decontamination and protection purposes. To better understand the chemical nature of the interactions of organophosphonate simulants with these surfaces, an ultra-high vacuum environment was used to isolate the target interactions from environmental gaseous interferences. The use of highly-characterized surfaces, coupled with molecular beam and dosing capabilities, allows for the elucidation of adsorption, desorption, and reaction mechanisms of CWA simulants on a variety of materials.
Model urethane-containing organic coatings were designed and applied toward the creation of well-ordered thin films containing carbamate linkages. In addition, novel trisilanolphenyl-polyhedral oligomeric silsesquioxane (POSS) molecules were used to create Langmuir-Blodgett films containing reactive silanol groups that have potential use as sensors and coatings. The uptake and reactivity of organophosphonates and chlorophosphates on these surfaces is the focus of this study.
Surfaces were characterized before and after exposure to the phosphates using a number of surface sensitive techniques including: contact angle goniometry, reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) measurements. In conjunction with surface probes, uptake coefficients were monitored according to the King and Wells direct reflection technique. The integration of these analytical techniques provides insight and direction towards the design of more effective chemical agent resistant coatings and aids in the development of more functional strategies for chemical warfare agent decontamination and sensing.Ph. D.
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Uzarski, Joshua Robert. "Reflection Absorption Infrared Spectroscopic Studies of Surface Chemistry Relevant to Chemical and Biological Warfare Agent Defense." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26107.
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Reflection absorption infrared spectroscopy was used as the primary analysis technique to study the interfacial chemistry of surfaces relevant to chemical and biological warfare agent defense. Many strategies utilized by the military to detect and decompose chemical and biological warfare agents involve their interaction with surfaces. However, much of the chemistry that occurs at the interface between the agents and surfaces of interest remains unknown. The surface chemistry plays an important role in efficacy of both detection and decontamination technology, and by obtaining a deeper understanding of that chemistry, researchers might be able to develop more sensitive detection devices and more effective decontamination strategies. Our efforts have focused on three different areas of surface chemistry relevant to chemical and biological warfare agent defense:
1) The development of a surface synthesis strategy to create and control the structure of antibacterial self-assembled monolayers (SAMs). Our work demonstrated a successful strategy for creating SAMs that contain long-chain quaternary ammonium groups, which were synthesized and subsequently characterized using RAIRS and X-ray photoelectron spectroscopy (XPS).
2) The determination of the surface conformation, orientation, and relative surface density of immobilized antimicrobial peptides. Our results revealed that the peptides consisted of tilted (50-60°), α-helices on the surface, regardless of solution conditions.
3) The design and construction of a new ultrahigh vacuum surface science instrument that allows for the study of gas-surface reactions with up to three gases simultaneously.
4) The study of the adsorption of chemical warfare agent simulants to silica nanoparticulate films. Our work demonstrated that the adsorbate structure was dependent on the number of hydrogen-bonding groups, and the adsorption consists of a pressure-dependent two part mechanism.
The results presented here will help increase the understanding of the surface chemistry of three interfaces relevant to chemical and biological defense. Future researchers may apply the new information to develop more effective detection and decontamination strategies for chemical and biological warfare agents.Ph. D.
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Wilmsmeyer, Amanda Rose. "Ultrahigh Vacuum Studies of the Fundamental Interactions of Chemical Warfare Agents and Their Simulants with Amorphous Silica." Diss., Virginia Polytechnic Institute and State University, 2012. http://hdl.handle.net/10919/54366.
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Developing a fundamental understanding of the interactions of chemical warfare agents (CWAs) with surfaces is essential for the rational design of new sorbents, sensors, and decontamination strategies. The interactions of chemical warfare agent simulants, molecules which retain many of the same chemical or physical properties of the agent without the toxic effects, with amorphous silica were conducted to investigate how small changes in chemical structure affect the overall chemistry. Experiments investigating the surface chemistry of two classes of CWAs, nerve and blister agents, were performed in ultrahigh vacuum to provide a well-characterized system in the absence of background gases. Transmission infrared spectroscopy and temperature-programmed desorption techniques were used to learn about the adsorption mechanism and to measure the activation energy for desorption for each of the simulant studied. In the organophosphate series, the simulants diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), trimethyl phosphate (TMP), dimethyl chlorophosphate (DMCP), and methyl dichlorophosphate (MDCP) were all observed to interact with the silica surface through the formation of a hydrogen bond between the phosphoryl oxygen of the simulant and an isolated hydroxyl group on the surface. In the limit of zero coverage, and after defect effects were excluded, the activation energies for desorption were measured to be 57.9 ± 1, 54.5 ± 0.3, 52.4 ± 0.6, 48.4 ± 1, and 43.0 ± 0.8 kJ/mol for DIMP. DMMP, TMP, DMCP, and MDCP respectively. The adsorption strength was linearly correlated to the magnitude of the frequency shift of the ν(SiO-H) mode upon simulant adsorption. The interaction strength was also linearly correlated to the calculated negative charge on the phosphoryl oxygen, which is affected by the combined inductive effects of the simulants’ different substituents. From the structure-function relationship provided by the simulant studies, the CWA, Sarin is predicted to adsorb to isolated hydroxyl groups of the silica surface via the phosphoryl oxygen with a strength of 53 kJ/mol. The interactions of two common mustard simulants, 2-chloroethyl ethyl sulfide (2-CEES) and methyl salicylate (MeS), with amorphous silica were also studied. 2-CEES was observed to adsorb to form two different types of hydrogen bonds with isolated hydroxyl groups, one via the S moiety and another via the Cl moiety. The desorption energy depends strongly on the simulant coverage, suggesting that each 2-CEES adsorbate forms two hydrogen bonds. MeS interacts with the surface via a single hydrogen bond through either its hydroxyl or carbonyl functionality. While the simulant work has allowed us to make predictions agent-surface interactions, actual experiments with the live agents need to be conducted to fully understand this chemistry. To this end, a new surface science instrument specifically designed for agent-surface experiments has been developed, constructed, and tested. The instrument, located at Edgewood Chemical Biological Center, now makes it possible to make direct comparisons between simulants and agents that will aid in choosing which simulants best model live agent chemistry for a given system. These fundamental studies will also contribute to the development of new agent detection and decontamination strategies.Ph. D.
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Wang, Guanyu. "Interfacial Energy Transfer in Small Hydrocarbon Collisions with Organic Surfaces and the Decomposition of Chemical Warfare Agent Simulants within Metal-Organic Frameworks." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100746.
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A molecular-level understanding of gas-surface energy exchange and reaction mechanisms will aid in the prediction of the environmental fate of pollutants and enable advances toward catalysts for the decomposition of toxic compounds. To this end, molecular beam scattering experiments performed in an ultra-high vacuum environment have provided key insights into the initial collision and outcome of critical interfacial processes on model systems.
Results from these surface science experiments show that, upon gas-surface collisions, energy transfer depends, in subtle ways, on both the properties of the gas molecules and surfaces. Specifically, model organic surfaces, comprised of long-chain methyl- and hydroxyl-terminated self-assembled monolayers (SAMs) have been employed to test how an interfacial hydrogen bonding network may affect the ability of a gas-phase compound to thermally accommodate (typically, the first step in a reaction) with the surfaces. Results indeed show that small organic compounds transfer less energy to the interconnected hydroxyl-terminated SAM (OH-SAM) than to the organic surface with methyl groups at the interface. However, the dynamics also appear to depend on the polarizability of the impinging gas-phase molecule. The π electrons in the double bond of ethene (C2H4) and the triple bond in ethyne (C2H2) appear to act as hydrogen bond acceptors when the molecules collide with the OH-SAM. The molecular beam scattering studies have demonstrated that these weak attractive forces facilitate energy transfer. A positive correlation between energy transfer and solubilities for analogous solute-solvent combinations was observed for the CH3-SAM (TD fractions: C2H6 > C2H4 > C2H2), but not for the OH-SAM (TD fractions: C2H6 > C2H2 > C2H4). The extent of energy transfer between ethane, ethene, and ethyne and the CH3-SAM appears to be determined by the degrees of freedom or rigidity of the impinging compound, while gas-surface attractive forces play a more decisive role in controlling the scattering dynamics at the OH-SAM.
Beyond fundamental studies of energy transfer, this thesis provides detailed surface-science-based studies of the mechanisms involved in the uptake and decomposition of chemical warfare agent (CWA) simulants on or within metal-organic frameworks (MOFs). The work presented here represents the first such study reported in with traditional surface-science based methods have been applied to the study of MOF chemistry. The mechanism and kinetics of interactions between dimethyl methylphosphonate (DMMP) or dimethyl chlorophosphate (DMCP), key CWA simulants, and Zr6-based metal-organic frameworks (MOFs) have been investigated with in situ infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), and DFT calculations. DMMP and DMCP were found to adsorb molecularly (physisorption) to the MOFs through the formation of hydrogen bonds between the phosphoryl oxygen and the free hydroxyl groups associated with Zr6 nodes or dangling -COH groups on the surface of crystallites. Unlike UiO-66, the infrared spectra for UiO-67 and MOF-808, recorded during DMMP exposure, suggest that uptake occurs through both physisorption and chemisorption. The XPS spectra of MOF-808 zirconium 3d electrons reveal a charge redistribution following exposure to DMMP. Besides, the analysis of the phosphorus 2p electrons following exposure and thermal annealing to 600 K indicates that two types of stable phosphorus-containing species exist within the MOF. DFT calculations (performed by Professor Troya at Virginia Tech), were used to guide the IR band assignments and to help interpret the XPS features, suggest that uptake is driven by nucleophilic addition of a surface OH group to DMMP with subsequent elimination of a methoxy substituent to form strongly bound methyl methylphosphonic acid (MMPA). With similar IR features of MOF-808 upon DMCP exposure, the reaction pathway of DMCP in Zr6-MOFs may be similar to that for DMMP, but with the final product being methyl chlorophosphonic acid (elimination of the chlorine) or MMPA (elimination of a methoxy group). The rates of product formation upon DMMP exposure of the MOFs suggest that there are two distinct uptake processes. The rate constants for these processes were found to differ by approximately an order of magnitude. However, the rates of molecular uptake were found to be nearly identical to the rates of reaction, which strongly suggests that the reaction rates are diffusion limited. Overall, and perhaps most importantly, this research has demonstrated that the final products inhibit further reactions within the MOFs. The strongly bound products could not be thermally driven from the MOFs prior to the decomposition of the MOFs themselves. Therefore, new materials are needed before the ultimate goal of creating a catalyst for the air-based destruction of traditional chemical nerve agents is realized.Doctor of Philosophy
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Chapleski, Jr Robert Charles. "Computational Investigations at the Gas-Surface Interface: Organic Surface Oxidation and Hydrolysis of Chemical Warfare Agents and Simulants." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77514.
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Motivated by recent experiments in gas-surface chemistry, we report our results from computational investigations of heterogeneous systems relevant to atmospheric chemistry and protection against chemical weapons. To elucidate findings of ultra-high vacuum experiments that probe the oxidation of carbon-carbon double bonds on model surfaces, we used electronic structure and QM/MM methods to study the reaction of ozone with C60-fullerene and the products of nitrate addition to a vinyl-terminated self-assembled monolayer. In the first system, we followed a reaction pathway beginning with primary ozonide formation through the formation of stable products. Theoretical vibrational spectra were used to identify a ketene product in prior experimental work. Next, through the construction of a multilayer model for the initial addition product of a nitrate radical to a chain embedded within a self-assembled monolayer, we report theoretical spectra that are consistent with experimental results. We then examined the fundamentals of the hydrolysis mechanism for nerve agents by a catalyst of interest in the development of filtration materials for chemical-warfare-agent defense. By following the gas-surface reaction pathway of the nerve agent Sarin on the Lindqvist polyoxoniobate Cs8Nb6O19, we determined that the rate-limiting step is the transfer of a proton from an adsorbed water molecule to the niobate surface, concomitant with the nucleophilic addition of the nascent hydroxide to the phosphorus atom in Sarin. Our results support a general base hydrolysis mechanism, though high product-adsorption energies suggest that thermal treatment of the system is required to fully regenerate the catalyst. We report similar mechanisms for the simulants dimethyl methylphosphonate and dimethyl chlorophosphate, though the latter may serve as a better simulant in studies of this type. Finally, an investigation of Sarin hydrolysis with solvated Cs8Nb6O19 shows an increase in the rate-limiting barrier relative to the gas-surface system, revealing the role of Cs counterions in the reaction. Then, we further increased explicit solvation to model the homogeneous solution-phase reaction, finding a different mechanism in which a water molecule adds to phosphorus in the rate-limiting step and protonation of the niobate surface occurs in a subsequent barrierless step. By examining the rate-limiting barrier for protonation, we suggest that specific base hydrolysis is also likely in the homogeneous system.Ph. D.
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Sharp, Conor Hays. "Fundamental Studies of the Uptake and Diffusion of Sulfur Mustard Simulants within Zirconium-based Metal-Organic Frameworks." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102928.
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The threat of chemical warfare agent (CWA) attacks has persisted into the 21st century due to the actions of terror groups and rogue states. Traditional filtration strategies for soldier protection rely on high surface area activated carbon, but these materials merely trap CWAs through weak physisorption. Metal-organic frameworks (MOFs) have emerged as promising materials to catalyze the degradation of CWAs into significantly less toxic byproducts. The precise synthetic control over the porosity, defect density, and chemical functionality of MOFs offer exciting potential of for use in CWA degradation as well as a wide variety of other applications. Developing a molecular-level understanding of gas-MOF interactions can allow for the rational design of MOFs optimized for CWA degradation. Our research investigated the fundamental interfacial interactions between CWA simulant vapors, specifically sulfur mustard (HD) simulants, and zirconium-based MOFs (Zr-MOFs). Utilizing a custom-built ultrahigh vacuum chamber with infrared spectroscopic and mass spectrometric capabilities, the adsorption mechanism, diffusion energetics, and diffusion kinetics of HD simulants were determined. For 2-chloroethyl ethyl sulfide (2-CEES), a widely used HD simulant, infrared spectroscopy revealed that adsorption within Zr-MOFs primarily proceeded through hydrogen bond formation between 2-CEES and the bridging hydroxyls on the secondary building unit of the MOFs. Through the study of 1-chloropentane and diethyl sulfide adsorption, we determined that 2-CEES forms hydrogen bonds through its chlorine atom likely due to geometric constraints within the MOF pore environment. Temperature-programmed desorption experiments aimed at determining desorption energetics reveal that 2-CEES remain adsorbed within the pores of the MOFs until high temperatures, but traditional methods of TPD analysis fail to accurately measure both the enthalpic and entropic interactions of 2-CEES desorption from a single adsorption site. Infrared spectroscopy was able to measure the diffusion of adsorbates within MOFs by tracking the rate of decrease in overall adsorbate concentrations at several temperatures. The results indicate that 2-CEES diffusion through the pores of the MOFs is a slow, activated process that is affected by the size of the pore windows and presence of hydrogen bonding sites. We speculate that diffusion is the rate limiting step in the desorption of HD simulants through Zr-MOFs at lower temperatures. Stochastic simulations were performed in an attempt to deconvolute TPD data in order to extract desorption parameters. Finally, a combination of vacuum-based and ambient-pressure spectroscopic techniques were employed to study the reaction between 2-CEES and an amine-functionalized MOF, UiO-66-NH2. Although the presence of water adsorbed within UiO 66 NH2 under ambient conditions may assist in the reactive adsorption of 2-CEES, the reaction proceeded under anhydrous conditions.Doctor of Philosophy
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Kittle, Joshua D. "Quartz Crystal Microbalance Studies of Dimethyl Methylphosphonate Sorption Into Trisilanolphenyl-Poss Films." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35688.
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Developing methods to detect, adsorb, and decompose chemical warfare agents (CWAs) is of critical importance to protecting military and civilian populations alike. The sorption of dimethyl methylphosphonate (DMMP), a CWA simulant, into trisilanolphenyl-POSS (TPP) films has previously been characterized with reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and uptake coefficient determinations [1]. In our study, the quartz crystal microbalance (QCM) is used to study the sorption phenomena of DMMP into highly ordered Langmuir-Blodgett (LB) films of TPP. In a saturated environment, DMMP sorbs into the TPP films, binding to TPP in a 1:1 molar ratio. Although previous work indicated these DMMP-saturated films were stable for several weeks, DMMP is found to slowly desorb from the TPP films at room temperature and pressure. Upon application of vacuum to the DMMP-saturated films, DMMP follows first-order desorption kinetics and readily desorbs from the film, returning the TPP film to its original state.
[1] Ferguson-McPherson, M.; Low, E.; Esker, A.; Morris, J. J. Phys. Chem. B. 2005, 109, 18914.Master of Science
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Boglarski, Stephen L. "Application of hydrogen bond acidic polycarbosilane polymers and solid phase microextraction for the collection of nerve agent simulant /." Download the thesis in PDF, 2006. http://www.lrc.usuhs.mil/dissertations/pdf/Boglarski2006.pdf.
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Holman, Charles E. "Predicting biological warfare agent detector performance." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3091.
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Thesis (Ph.D.)--George Mason University, 2008.Vita: p. 232. Thesis director: Andrew Loerch. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biodefense. Title from PDF t.p. (viewed July 7, 2008). Includes bibliographical references (p. 226-231). Also issued in print.
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Sundberg, Jeffrey P. "U.S. chemical warfare stockpile vulnerability effects to local infrastructure from a chemical-agent release." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FSundberg.pdf.
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Subramaniam, Raja. "Simplified Routines for Sample Preparation and Analysis of Chemical Warfare Agent Degradation Products." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-54639.
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The thesis describes the development of new and improved methods for analyzing degradation markers from organophosphorus Chemical Warfare Agents (CWAs). Paper I and II describes an innovative and significantly improved method for the enrichment, derivatization (trimethysilylation) and GC-MS analysis of a broad range of organophosphorus CWAs degradation markers, namely the alkylphosphonic acids and a zwitterionic compound. That was achieved using solid phase disc extraction in combination with solid phase derivatization. The new method overcomes most limitations observed with existing techniques: it offers almost 100 % recoveries, requires no elution or evaporation steps, facilitates miniaturization of the solid sorbent and reagent, is compatible with in-vial derivatization, and minimizes the chromatographic background due to the use of a highly selective anion exchange sorbent disc. Paper III describes the development of new fluorinated diazomethane derivatization reagents and their evaluation for rapid and high sensitivity screening and identification of nerve agent degradation markers. The reagents are water-tolerant to some extent, which simplifies the derivatization step. The best reagent identified was 3,5-bis(trifluoromethyl)benzyl diazomethane, which outperformed the other reagent isomers tested and also the established commercial alternative, pentafluorobenzylbromide, allowing for the rapid (5 min) and direct derivatization of a 25 μL aqueous sample in acetonitrile. The spectra of the formed derivatives (high-energy collision induced fragmentation MS/MS) were used to construct a database (Paper IV) that proved to be superior in terms of match factor and probability compared to EI data gathered for trimethylsilyl derivatives. The study also focused on efforts towards achieving detailed structure information on the alkyl chains of the compounds in question using diagnostic ion interpretation. The final paper (paper V) describes the first rapid direct derivatization method for analyzing nerve agent metabolites in urine at trace levels. The method is based on the derivative from the paper III and the unambiguous identification was proven using a combination of low resolution and high resolution negative ion chemical ionization selected ion monitoring techniques. Novel results presented in these papers include: the first in-situ derivatization of alkylphosphonic acids on an SPE disc; the first direct derivatization of nerve agent markers in water and biomedical samples; the first high sensitivity GC-MS screening for these markers; and the first highly reproducible high-energy isomer specific CID MS/MS library. Overall, the results presented in this thesis represent significant contributions to the analysis of nerve agent degradation products.
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Richardson, Douglas Dennis. "Modern advancements in elemental speciation from sample introduction to chemical warfare agent detection /." Cincinnati, Ohio : University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1250178457.
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Thesis (Ph.D.)--University of Cincinnati, 2007.Advisor: Joseph A. Caruso. Title from electronic thesis title page (viewed Apr. 30, 2010). Keywords: Elemental Speciation; ICPMS; Chemical Warfare Agents; Phosphorus; Liquid Chromatography; Gas Chromatography; Capillary Electrophoresis. Includes abstract. Includes bibliographical references.
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Beck, Jeremy M. "Organophosphorus nerve agent chemistry; interactions of chemical warfare agents and their therapeutics with acetylcholinesterase." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313416337.
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Richardson, Douglas Dennis II. "Modern Advancements in Elemental Speciation: From Sample Introduction to Chemical Warefare Agent Detection." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250178457.
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Manoosingh, Lane Leslie. "Design of a chemical agent detector based on polymer coated surface acoustic wave (SAW) resonator technology." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000412.
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Brown, Jason David. "Development of an Effective Therapeutic for Nerve Agent Inhibited and Aged Acetylcholinesterase." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1334341199.
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Selbe, Tyler J. "Applications of aluminosilicate and zincosilicate materials: aqueous phase ion exchange and gas phase adsorption." Diss., Kansas State University, 2010. http://hdl.handle.net/2097/7057.
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Doctor of PhilosophyDepartment of Chemical Engineering
Jennifer L. Anthony
Zeolites and zeolite-like materials have well-ordered structures and pores creating varying capacities for molecules based upon size, functional groups, polarity, and intermolecular forces making the materials useful for molecular sensing as well for molecules that are considered hazardous at very low concentrations with reproducible results because of these properties. This study will identify and characterize applications for zeolite and zeolite-like materials in gas and liquid phases based upon the dominating physical and chemical properties of the materials. The properties of interest include liquid phase ion exchange capacities, selectivities, gas/vapor phase adsorption capacity, and initial adsorption uptake rate. Zincosilicates have similar framework structures to aluminosilicate zeolites; however, they have distinct advantages over traditional zeolites. Zincosilicates typically have a higher ion density, lack “cages” in their structure which leads to all the cations being accessible for ion exchange, and have the ability to form three-membered rings which lead to large void spaces in their structure. These features lead to high capture capacities for divalent heavy metal mercury ions. In this work, the potential to use zincosilicates as ion exchangers such as VPI-7, VPI-9 and VPI-10 is presented. Results have shown that zincosilicates have capture capacities greater than traditional zeolites, even greater than those that have been synthesized with functional groups intended to increase metal sorption capacities. The selectivity coefficients in a binary ion exchange system were successfully modeled using the Gibbs-Donnan selectivity model. The selectivities for the zincosilicates were Pb>Na>Hg>K>Ca. Zeolites are also able to adsorb chemical species and therefore can be used as the recognition element in sensing devices. The sorption capacity of 2-chloroethyl ethyl sulfide, dimethyl methanephosphonate, ethanol, and n-butanethiol were examined with zeolites 13X, 4A, MCM-41, VPI-7, VPI-9, and ZSM-5. The zeolites selected provided very different framework composition, countercation, and surface area features for determining the most significant properties in adsorption. Zeolite 13X had the highest equilibrium and initial uptake rate for most compounds tested, whereas the low surface area zincosilicates, VPI-7 and VPI-9, had the lowest capacity. Based on these results, a piezoelectric device with an array of zeolites can be successfully employed as a sensor.
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Driscoll, Darren Matthew. "Spectroscopic Studies of Small Molecule Adsorption and Oxidation on TiO2-Supported Coinage Metals and Zr6-based Metal-Organic Frameworks." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100685.
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Developing a fundamental understanding of the interactions between catalytic surfaces and adsorbed molecules is imperative to the rational design of new materials for catalytic, sorption and gas separation applications. Experiments that probed the chemistry at the gas-surface interface were employed through the utilization of in situ infrared spectroscopic measurements in high vacuum conditions to allow for detailed and systematic investigations into adsorption and reactive processes. Specifically, the mechanistic details of propene epoxidation on the surface of nanoparticulate Au supported on TiO2 and dimethyl chlorophosphate (DMCP) decomposition on the surface of TiO2 aerogel-supported Cu nanoparticles were investigated. In situ infrared spectroscopy illustrates that TiO2-supported Au nanoparticles exhibit the unprecedented ability to produce the industrially relevant commodity chemical, propene oxide, through the unique adsorption configuration of propene on the surface of Au and a hydroperoxide intermediate (-OOH) in the presence of gaseous hydrogen and oxygen. Whereas, TiO2-supported Cu aerogels oxidize the organophosphate-based simulant, DMCP, into adsorbed CO at ambient environments. Through a variety of spectroscopic methods, each step in these oxidative pathways was investigated, including: adsorption, oxidation and reactivation of the supported-nanoparticle systems to develop full mechanistic pictures. Additionally, the perturbation of vibrational character of the probe molecule, CO, was employed to characterize the intrinsic µ3-hydroxyls and molecular-level defects associated with the metal-organic framework (MOF), UiO-66. The adsorption of CO onto heterogeneous surfaces effectively characterizes surfaces because the C-O bond vibrates differently depending on the nature of the surface site. Therefore, CO adsorption was used within the high vacuum environment to identify atomic-level characteristics that traditional methods of analysis cannot distinguish.Doctor of Philosophy
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Jeffery, Brandon Reed. "Design and Construction of a High Vacuum Surface Analysis Instrument to Study Chemistry at Nanoparticulate Surfaces." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76776.
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Metal oxide and metal oxide-supported metal nanoparticles can adsorb and decompose chemical warfare agents (CWAs) and their simulants. Nanoparticle activity depends on several factors including chemical composition, particle size, and support, resulting in a vast number of materials with potential applications in CWA decontamination. Current instrumentation in our laboratory used to investigate fundamental gas-surface interactions require extensive time and effort to achieve operating conditions.
This thesis describes the design and construction of a high-throughput, high vacuum surface analysis instrument capable of studying interactions between CWA simulants and nanoparticulate surfaces. The new instrument is small, relatively inexpensive, and easy to use, allowing for expeditious investigations of fundamental interactions between gasses and nanoparticulate samples. The instrument maintains the sample under high vacuum (10?⁷-10?⁹ torr) and can reach operating pressures in less than one hour. Thermal control of the sample from 150-800 K enables sample cleaning and thermal desorption experiments. Infrared spectroscopic and mass spectrometric methods are used concurrently to study gas-surface interactions. Temperature programmed desorption is used to estimate binding strength of adsorbed species. Initial studies were conducted to assess the performance of the instrument and to investigate interactions between the CWA simulant dimethyl methylphosphonate (DMMP) and nanoparticulate silicon dioxide.Master of Science
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Spiandore, Marie. "Evaluation de la contamination et de la décontamination des cheveux après exposition à des agents chimiques toxiques." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4776.
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Comme l’a montré l’utilisation de sarin en Syrie en 2013, les agents chimiques de guerre restent une menace. L’exposition de populations est une situation d’urgence qui nécessite des moyens rapides et efficaces. La décontamination et le soin des personnes exposées restent une priorité. Les cheveux représentent une matrice couramment utilisée dans le domaine médico-légal. Dans ce travail, notre intérêt se porte sur la capacité du cheveu à capter et libérer des composés dans l’air, notamment l’ypérite, ainsi que sur l’efficacité de décontamination de cette matrice. Pour ce travail, nous avons utilisé deux composés aux propriétés physiques/chimiques proches de celles de l’ypérite : le salicylate de méthyle et le 2-chloroéthyl éthyl sulfure. Les deux similis ont été retenus par le cheveu avec une plus grande affinité pour le salicylate de méthyle. Nous avons observé une corrélation entre l’intensité d’exposition (influence de la dose et du temps) et la teneur en contaminants retrouvés sur les cheveux. Ces résultats montrent qu’il est possible d’utiliser le cheveu pour détecter une exposition individuelle. Après exposition, la teneur dans des cheveux laissés à désorber a été mesurée avec le salicylate de méthyle. Les résultats obtenus ont montré que les cheveux contaminés sont susceptibles de libérer les toxiques. Cela peut poser un problème sanitaire, qui implique donc que la décontamination des cheveux soit étudiée. Les protocoles de décontamination testés montrent une efficacité partielle (élimination de 40 à 80%). Ces résultats impliquent la nécessité d’optimiser les procédures actuelles ou de définir de nouveaux outils pour la décontamination du cheveu après expositionAs shown by sarin use in Syria (2013), chemical warfare agents remain a threat. Chemical exposure of populations is an emergency situation, where quick and efficient means are mandatory. Decontamination and care of the victims are a priority. Scalp hair is routinely used as a biological matrix in forensic sciences. In this thesis work, interest focuses on hair capacity to trap and release compounds from atmosphere, especially sulphur mustard, as well as decontamination of this matrix. For this work, two molecules with similar physical/chemical properties to sulphur mustard were used: methyl salicylate and 2-chloroethyl ethyl sulphide. Both simulants were trapped by scalp hair, with higher affinity towards methyl salicylate. We observed a correlation between exposure intensity (influence from dose and time) and simulant content recovered from hair analysis. Results suggest that hair can be used to assess individual contamination. After exposure, evolution of methyl salicylate hair content has been measured. Results pointed out that contaminated hair can thereafter release the simulants. This can lead to health issue, highlighting the fact that hair decontamination must be investigated. Tested decontamination protocols showed a partial efficacy (40-80% removal). Those results evidenced the need to optimise current procedures or define new tools for hair decontamination after chemical exposure
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Parrish, Douglas K. "Application of solid phase microextraction with gas chromatography-mass spectrometry as a rapid, reliable, and safe method for field sampling and analysis of chemical warfare agent precursors /." Download the dissertation in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Parrish2005.pdf.
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Grissom, Tyler Glenn. "Fundamental Investigations of Hazardous Gas Uptake and Binding in Metal-Organic Frameworks and Polyurethane Films." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/101079.
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The advancements of chemists, engineers, and material scientists has yielded an enormous and diverse library of high-performance materials with varying chemical and physical properties that can be used in a wide array of applications. A molecular-level understanding of the nature of gas–surface interactions is critical to the development of next generation materials for applications such as gas storage and separation, chemical sensing, catalysis, energy conversion, and protective coatings. Quartz crystal microbalance (QCM) and in situ infrared (IR) spectroscopic techniques were employed to probe how topological features of a material as well as structural differences of the analytes affect gas sorption. Detailed studies of the interactions of three categories of molecules: aromatic hydrocarbons, triatomic ambient gases, and chemical warfare agents, with metal-organic frameworks (MOFs) and polyurethane coatings were conducted to build structure–property relationships for the nature and energetics of gas sorption within each material. Differences in the molecular structure of the guest compounds were found to greatly influence how, and to what extent each molecule interacts with the MOF or polyurethane film. Specifically, IR studies revealed that transport of aromatic compounds within the zirconium-based MOF, UiO-66 was limited by steric restrictions as molecules passed through small triangular apertures within the pore environment of the MOF. In contrast, the smaller triatomic molecules, CO2, SO2, and NO2, were able to pass freely through the MOF apertures and instead reversibly adsorbed inside the MOF cavities. Specifically, SO2 and NO2 were observed to preferentially bind to undercoordinated zirconium sites located on the MOF nodes. In addition, uptake of CO2, SO2, and NO2 was also aided by dispersion forces within the confined pore environments and by hydrogen bond formation with μ3 OH groups of the MOFs. Dimethyl chlorophosphate (DMCP), a nerve agent simulant that contains several electronegative moieties, was also found to strongly adsorb to undercoordinated zirconium; however, unlike in the aromatic and triatomic molecule systems, DMCP remained permanently bound to the MOFs, even at high temperatures. Finally, QCM studies of mustard gas simulant uptake into polyurethane films of varying hard:soft segment compositions revealed that dipole-dipole and dipole-induced dipole interactions were responsible for favorable absorption conditions. Furthermore, the ratio of hard and soft segment components of the polyurethane had a minor impact on simulant adsorption. Higher hard-segment content resulted in a more crystalline film that reduced simulant uptake, whereas the rubbery, high soft segment polyurethane allowed for greater vapor absorption. Ultimately, molecular-level insight into how the chemical identity of a guest molecule impacts the mechanism and energetics of vapor sorption into both MOFs and polymeric films can be extended to other relevant systems and may help identify how specific characteristics of each material, such as size, shape, and chemical functionality impact their potential use in targeted applications.Doctor of Philosophy
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Koske, Daniel [Verfasser], Reinhold [Akademischer Betreuer] Hanel, and Eric [Gutachter] Achterberg. "Dumped munitions : Effects, metabolism and detection of explosive compounds and chemical warfare agent-related chemicals in fish from the Baltic Sea / Daniel Koske ; Gutachter: Eric Achterberg ; Betreuer: Reinhold Hanel." Kiel : Universitätsbibliothek Kiel, 2020. http://d-nb.info/1221599771/34.
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Bignon, Cécile. "Nanoparticules en réseau pour la protection cutanée." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4084/document.
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Les agents chimiques de guerre et leurs dérivés pesticides sont des molécules toxiques qui provoquent une incapacité temporaire ou des dommages permanents allant jusqu’à la mort de l’individu. Une des voies majeures de la contamination est la pénétration cutanée. La protection de la peau semble donc importante pour prévenir de ces dangers. Cette thèse concerne l’élaboration de nouveaux topiques protecteurs cutanés contenant des polymères HASE fluorés greffés avec des nanoparticules de silice, cérine ou titane. Dans un premier temps les actifs ont été synthétisés en grosse quantité et leurs propriétés de mouillabilité améliorées. Les tests toxicologiques ont montré que les actifs n’étaient pas irritants pour la peau et non toxiques pour l’environnement. La formulation de ces polymères a permis le développement de deux nouvelles crèmes barrières contre la pénétration du paraoxon dont l’efficacité est dépendante de la présence des nanoparticules. Le greffage des nanoparticules à un polymère HASE fluoré et leur formulation a donc permis le développement de nouveaux topiques efficaces. L’évaluation de l’efficacité a été réalisée sur membranes artificielles et confirmée sur explants de peaux humaines. Enfin, le peu de disponibilité des explants de peaux humaines a motivé le développement d’un modèle d’efficacité utilisant des épidermes humains reconstruitsChemical warfare agents and pesticides are toxic molecules causing temporary incapacitation or permanent harms leading to the death of people. One of the major routes of contamination is the percutaneous penetration. Skin protection is important to prevent these dangers. The aim of this thesis is to develop new active topical skin protectants based on nanoparticular networks containing fluorinated HASE polymers grafting with silica, cerium or titanium nanoparticles. First, polymers were synthesized in larger quantity and their wettability properties improved. Toxicological studies have showed that these compounds are non-irritant and non-toxic for the environment. The formulation of these polymers has led to the elaboration of two new barrier creams against paraoxon penetration whose efficiency is dependent on the presence of nanoparticles. Therefore, the grafting of nanoparticles to fluorinated HASE polymer and their formulation have enabled the development of new active topical skin protectant. Efficiency evaluation was done using artificial membranes and was confirmed on ex vivo human skin. The limited availability of human skin explants has motivated the development of a new efficiency model using reconstructed human epidermis
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Rolland, Pauline. "Décontamination du cuir chevelu humain après exposition aux agents chimiques de guerre." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10215.
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Les neurotoxiques organophosphorés sont appelés agents chimiques de guerre car ils sont une menace à la fois pour les militaires et pour les populations civiles. La voie percutanée est l’une des principales voies d’entrée pour ces agents, et plus particulièrement pour le VX, très peu volatil. La décontamination des surfaces exposées est alors cruciale afin d’éviter l’intoxication des victimes. En cas d’attentat terroriste, le cuir chevelu humain pourrait être un site préférentiel d’exposition. Cette partie du corps, riche en follicules pileux, pourrait nécessiter des produits et des processus de décontamination adaptés. Ce travail est divisé en 4 parties : 1) Validation d’un modèle de peau in vitro pour le cuir chevelu humain ; 2) Détermination des stratégies de décontamination ; 3) Formulation de nouveaux systèmes de décontamination ; 4) Évaluation de leur efficacité de décontamination. La peau d’oreille de porc est un modèle pertinent pour l’étude de la pénétration percutanée in vitro du VX à travers le cuir chevelu humain. La peau de dessus de tête de porc représente un bon modèle de cuir chevelu humain pour l’étude de l’affinité du VX avec la tige pilaire. L’étude de distribution du VX selon différents temps d’exposition a montré que la majorité du toxique reste à la surface de la peau jusqu’à 2h d’exposition. Il est donc intéressant de décontaminer la peau même après 2h d’exposition aux agents chimiques de guerre. Les microémulsions comprenant un actif détoxifiant (oxime) sont les systèmes les plus efficaces car ils pénètrent en profondeur afin de venir détruire le toxique in situ dans la peau. Les poudres et les émulsions de Pickering ont une action de surface et permettent d’extraire le toxique présent à la surface de la peau et dans les couches superficielles. Les résultats de nos études in vitro ont montré que ces formulations sont significativement plus efficaces que la terre à foulon pour une décontamination après 45 min d’exposition au VXOrganophosphorous nerve agents are designed as chemical warfare agent because they represent a threat both for the military and the civilians. Due to its low volatility, VX mainly remains in its liquid form and mostly presents a contamination by skin contact. Decontamination of exposed body surface is therefore crucial to prevent victims' poisoning. In case of terrorist acts, civilian human scalp could be a preferential site of exposure. This body region, rich in hair follicles, may require adapted decontamination products and procedures. The aims of this work are: 1) Validation of a relevant in vitro human scalp skin model; 2) Determination of decontamination strategies; 3) Formulation of new decontamination systems; 4) Evaluation of their decontamination efficacy. Pig ear skin is a relevant model when studying the in vitro percutaneous penetration of VX through human scalp. Pig skull roof skin could be used when studying the affinity of VX for hair. This study has shown that most of the nerve agent remains on the skin surface up to 2h of exposure, which means that it is worth decontaminating even if contamination occurred 2h before. Microemulsions loading a detoxifying agent (oxime) are the most efficient systems because they are able to penetrate deeper into the skin to neutralize the agent in situ. Adsorbing powders and Pickering emulsions could interact with the agent present on the skin surface and in the superficial layers. Our results from the in vitro experiments have demonstrated that these formulations are more efficient than Fuller's earth for skin decontamination after 45 min of VX exposure
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McKenna, Josiah Michael. "Paper spray mass spectrometry (PS-MS) for toxicological drug screens and biomonitoring of chemical warfare agent exposure." Thesis, 2017. https://doi.org/10.7912/C2TQ04.
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Indiana University-Purdue University Indianapolis (IUPUI)Paper spray is an ambient ionization technique for mass spectrometry that is well-known for its ability to accomplish rapid and sensitive analyses without any need for sample preparation. This work further develops the technique in two major areas: negative ionization and drug screening. Negative ionization has always been an obstacle to electrospray-based ion sources because of its vulnerability to corona discharge, but methods are presented here to both quantify and suppress this electrical phenomenon, thus preventing it from interfering with qualitative/quantitative analyses. The validity of the discharge-suppressing method is demonstrated for both a simple screen of barbiturates and other acidic drugs (Chapter 2) and the detection and quantitation of chemical warfare agent hydrolysis products (Chapter 3). Additionally, a positive ion drug screen is applied to the analysis of postmortem blood samples (Chapter 4), achieving rapid and effective screening of 137 different drugs ranging from pharmaceuticals to drugs of abuse. The performance of this screen is also evaluated by comparing the results of the postmortem samples to those obtained using a more established series of assays. The research contained herein presents strides toward forensic application of paper spray mass spectrometry, especially in disciplines related to forensic toxicology.
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Chang, Ching-Fui, and 張進福. "Feasibility Studies on the Use of Sea Water for Preparation of Decontamination Agent for Combating Chemical Warfare Agents." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43369459080361067804.
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碩士元智大學
化學工程學系
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表2-1 神經性毒劑主要物理性質 6 表2-2 神經性毒劑對人的毒性 8 表2-3芥子氣、路易氏劑及氮芥氣的主要物理性質 11 表2-4 液滴態糜爛性毒劑對人的皮膚毒性 12 表2-5 芥子氣不同途徑的毒性 13 表2-6 氫氰酸和氯化氰的主要物理性質 14 表2-7 氫氰酸和氯化氰吸入毒性 15 表2-8 光氣、雙光氣主要物理性質 17 表2-9 光氣對人的毒性 18 表2-10 雙光氣對人的毒性 18 表2-11 刺激性毒劑的主要理化性質 20 表2-12 刺激性毒劑對人的毒性 21 表3-1 海水與河水離子成份比較表 28 表3-2 直讀式儀器各項測定值 34 表3-3 有效氯滴定程序及滴定時的顏色變化 37 表3-4 有效氯的滴定結果 38 表3-5 氣相分析儀儀器操作條件 41 表3-6 氣相分析儀溫控條件 41 表3-7 植物生長影響測試實驗步驟 49 表4-1不同基質調製的消除藥劑與不同濃度間的比例關係表 57 表4-2 經過168小時後，植物之生長情形 62 摘 要 本研究選用目前軍方現役消除劑：STB耐熱漂白粉與八二式消除劑，以海水與淡水調製後，對巴拉松進行化學消除測試、生物消除測試和植物生長影響測試，比較消除效能，並進行動力學推估。 化學消除測試是以濃度為100mg/L的巴拉松，與淡水和海水調製的消除劑反應，以了解消除效能的差異。生物消除測試是以淡水和海水調製的消除劑，對總菌落數為9920 CFU/ml之廢水進行消除，取樣進行總生菌數培養，驗證STB耐熱漂白粉和八二式消除劑的生物消除效能。植物生長影響測試則是以淡水和海水調製成濃度5000mg/L的消除劑，使用噴灑器均勻噴灑在固定面積的自然植披，168小時後，觀察消除藥劑對自然植披的影響。 化學消除測試的結果顯示，用海水調製國軍制式化學戰劑消除劑，其對化學戰劑的消除效能雖然會比淡水調製時稍差；但是還是可達到60﹪以上的消除效率。因為海水中的陽離子會與消除劑釋放的氯離子結合，形成鹽類，影響消除劑對化學戰劑的消除效能，減低消除劑的消除效果；所以若要提高消除效率，可用增加消除劑濃度的方法來解決；達到消除的目的。 生物消除實驗的結果顯示，不論是以海水或淡水為基質，濃度同為0.5ppm以上時，兩者的消除效率均趨近於100﹪。 由植物生長影響測試的結果顯示，以海水基質調製的消除劑對實驗區的植物生長影響較明顯。 綜合化學消除測試、生物消除測試與植物生長影響測試等三種測試結果再加上消除劑本身性質的特性，可以歸納出最佳消除藥劑與基質的搭配是八二式消除劑與淡水；顯示出八二式消除劑的性能遠優於STB耐熱漂白粉。所以經由實驗結果顯示：以海水為基質調製化學戰劑消除劑是確實可行的。 Abstract This research is to utilize fresh and sea water in preparing two decontamination agents (Super tropical bleach or STB and Type 82) which are currently used in the military. Research emphasis focuses on using these agents for decomposing parathion and for killing the bacteria in the water. The effect of the prepared agent on the grass growth is also considered. For all tests, stock solution of 100 mg/l parathion and pond water containing 9920 CFU/ml bacterial count were prepared. l tests. The test results on decontaminating chemical warfare agent (parathion) indicated that the decontamination agent prepared with sea water has been less effective than that prepared with fresh water. Still a decontamination efficiency of above 60% could be achieved for a decontamination agent of 10,000 mg/l. The reason for the reduced effectiveness of the former was apparently due to that the variuos cationic ions present in the sea water partially combine the chloride of the agent, resulting in formation of complex salts. However, the decontamination efficiency can be considerably elevated by using a decontamination agent with much higher concentration beyond 10,000 mg/l, as generally practiced in the military applications. For killing the bacteria, 0.5 mg/l decontamination agents prepared with fresh or sea water had a decontamination efficiency of nearly 100%. The effect of decontamination agent on the grass growth was found to be significant only for the one prepared with sea water. However, this effect of decontamination agent on the grass growth was found to disappear naturally in about one month after its application. Observation from all the test results reveals that freshwater is still the better medium for preparing the decontamination agent using STB or Type 82. The counterparts prepared with sea water were observed to be slightly less effective in decontaminating parathion. However, the reduced effectiveness can be more than compensated by elevating the agent concentration. It is hence concluded that the decontamination agents prepared with sea water is highly feasible and practical in the field applications.
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"Stimuli Responsive Barrier Materials for Breathable, Chemically-Protective Wearable Fabrics." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.62687.
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abstract: As experiencing hot months and thermal stresses is becoming more common, chemically protective fabrics must adapt and provide protections while reducing the heat stress to the body. These concerns affect first responders, warfighters, and workers regularly surrounded by hazardous chemical agents. While adapting traditional garments with cooling devices provides one route to mitigate this issue, these cooling methods add bulk, are time limited, and may not be applicable in locations without logistical support. Here I take inspiration from nature to guide the development of smart fabrics that have high breathability, but self-seal on exposure to target chemical(s), providing a better balance between cooling and protection.
Natural barrier materials were explored as a guide, focusing specifically on prickly pear cacti. These cacti have a natural waxy barrier that provides protection from dehydration and physically changes shape to modify surface wettability and water vapor transport. The results of this study provided a basis for a shape changing polymer to be used to respond directly to hazardous chemicals, swelling to contain the agent.
To create a stimuli responsive material, a novel superabsorbent polymer was synthesized, based on acrylamide chemistry. The polymer was tested for swelling properties in a wide range of organic liquids and found to highly swell in moderately polar organic liquids. To help predict swelling in untested liquids, the swelling of multiple test liquids were compared with their thermodynamic properties to observe trends. As the smart fabric needs to remain breathable to allow evaporative cooling, while retaining functionality when soaked with sweat, absorption of water, as well as that of an absorbing liquid in the presence of water were tested.
Micron sized particles of the developed polymer were deposited on a plastic mesh with pore size and open area similar to common clothing fabric to establish the proof of concept of using a breathable barrier to provide chemical protection. The polymer coated mesh showed minimal additional resistance to water vapor transport, relative to the mesh alone, but blocked more than 99% of a xylene aerosol from penetrating the barrier.Dissertation/Thesis
Doctoral Dissertation Chemical Engineering 2020
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Millerioux, Jennifer. "Formulation et évaluation de la stabilité et de l’efficacité de topiques protecteurs vis-à-vis des composés organophosphorés." Thesis, 2009. http://www.theses.fr/2009LYO10039.
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Les neurotoxiques organophosphorés (NOP) sont extrêmement toxiques et peu volatils. Dans des conditions normales de température et de pression, ils peuvent pénétrer rapidement la peau sous forme liquide et exercer leurs effets délétères. En milieu civil ou militaire, leur utilisation potentielle est toujours redoutée. Le développement de dispositifs de protection cutanée vis-à-vis de ces agents est donc d’un intérêt majeur pour les armées et la sécurité civile. Dans ce contexte, les objectifs de ce travail ont été de formuler et évaluer la stabilité et l’efficacité de topiques protecteurs cutanés (TP) vis-à-vis des NOP. Le premier objectif a consisté à mettre au point des TP de compositions et de formes galéniques différentes (émulsions, gels) puis à valider leurs stabilités physicochimiques. Cent trente TP ont été formulés et 30 ont montré une stabilité physicochimique satisfaisante. Le second objectif a été d’évaluer l’efficacité des TP les plus prometteurs vis-à-vis des composés organophosphorés. Actuellement il n’existe pas de standardisation de ce type d’étude. Par conséquent, l’utilisation de plusieurs tests in vitro et in vivo (membranes biologiques ou synthétiques, NOP ou simili), dont la pertinence et la fiabilité ont été déterminées, nous a permis d’établir une logique de criblage pour l’évaluation de l’efficacité des TP. Parmi les 13 formulations testées, les résultats ont montré qu’un gel hydro-alcoolique apporte une protection cutanée significative et supérieure aux produits de référence testés vis-à-vis du VX, un NOP d’intérêtPrevention of exposure to the neurotoxic organophosphorus compounds (OP) that are quickly absorbed in the skin is a major concern both for pesticide users and soldiers. Skin barrier creams are being developed to complement or replace uncomfortable chemical protective suits. The objectives of this work were to formulate and assess physicochemical stability and protective efficacy of topical skin protectant (TSP) against OP compounds. The first objective was to formulate several different TSP (emulsions, gel) and validate their physicochemical stability.The second objective was to determine the consistency of results from in vitro tests and the importance of the formulation composition in the skin protective efficacy. Quick evaluation of formulations efficacy mainly relies on in vitro tests which lead to consistent, complementary and relevant results. Our results indicated that the least effective formulations could be quickly identified by performing in vitro permeation tests with silicone membrane and by evaluating interfacial interactions between formulations and OP. We showed that a hydrogel containing specific hydrophilic polymers was by far the most effective of the formulations evaluated against VX, OP compounds, skin permeation in vitro