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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

REMOVAL OF EMERGING CONTAMINANTS FROM AQUEOUS SOLUTION BY OZONE -BASED PROCESSES

Rani, Rupam January 2013 (has links)
The presence of emerging contaminants (ECs) in water and wastewater systems has become a subject of significant concern worldwide. These emerging contaminants are complex organic molecules which potentially affect human health and environment. Conventional wastewater treatment plants are unable to completely remove these contaminants from water and therefore can discharge them into environment. The need to develop effective methods for ECs removal is essential. This study assess the potential of ozone based advanced oxidation processes (AOP) to oxidize number of emerging contaminants. Different combinations of ozone with hydrogen peroxide and sodium persulfate were tested. For this study 1-4, dioxane, perfluorinated compounds (PFCs), N,N-Diethyl-metatoluamide, and three pharmaceuticals sulfamethoxazole, trimethoprim and carbamazepine have been selected. The effect of different process parameters such as chemical dosages, ozone weight percent, ozone flow rates, etc. on destruction of ECs were examined. It was observed that 1, 4-dioxane were persistent to direct ozone reaction, however were easily oxidized by hydroxyl radical. However, ozonation was solely very effective (> 99 %) in removing pharmaceuticals such as sulfamethoxaole, trimethoprim and carbamazepine. It was not very efficient for the removal of perfluorinated compound and N,N-Diethylmeta-toluamide. The operational conditions were optimized for maximum removal of every compound and their influence on the degradation process is discussed. / Civil Engineering
32

Sources, transport and fate of perfluoroalkyl acids in the atmosphere

Johansson, Jana January 2017 (has links)
Perfluoroalkyl acids (PFAAs) are man-made chemicals which have been observed in the global environment, even in locations far away from where they are emitted. These persistent substances are taken up in humans and biota and may have toxic effects. Knowledge about how PFAAs are dispersed in the environment is needed to discern strategies to manage their sources and to evaluate the efficacy of adopted legislation. This thesis aimed to increase our understanding of the sources of PFAAs to the atmosphere and how PFAAs are transported in air. The results of Paper I demonstrated that gaseous perfluorooctanoic acid (PFOA) sorbs to typical glass fibre filters (GFFs) used in high-volume air sampling of PFAAs. As a consequence, the fraction of gaseous PFOA present in sampled air is underestimated, while the fraction of PFOA associated with aerosols is overestimated. Replacing GFFs with filters deactivated through silanisation and siliconisation did not eliminate this sampling artefact and is therefore not recommended as a means to determine the gas-particle partitioning of PFAAs. In Paper II, monitoring of the mass of PFOA transferred from water solutions of pH 0.2-5.5 demonstrated that the acid dissociation constant of linear PFOA and the four most ubiquitous branched PFOA isomers is around or below 1. Furthermore, the results demonstrated that the presence of counter ions and organic matter in water retarded, rather than enhanced, the volatilisation of PFOA. Therefore, volatilisation of all isomers of PFOA from environmental waters is expected to be negligible. To further study the transfer of PFAAs from environmental waters to air, Paper III simulated the process of sea spray generation in the laboratory. Strong enrichment of PFAAs was observed from bulk water to the surface microlayer and to aerosols. The enrichment increased with PFAA chain length, indicating that this process is of greater importance for more surface active substances. The highest enrichment was observed in aerosols &lt; 1.6 µm, which can travel over long distances if not rained out. Based on the measured aerosol enrichment factors we estimated that approximately 70 metric tonnes of PFAAs are aerosolised from the global oceans yearly and that 3% of this mass is deposited in terrestrial environments. Paper IV reported the occurrence of branched PFOA isomers in deposition sampled in five geographical locations. The presence of these isomers demonstrated that atmospheric transformation of fluorotelomer alcohols is not the only ongoing source of PFAAs to air. We hypothesised that, additionally, both sea spray aerosols and direct emissions from manufacturing sources contributed to the contamination of the precipitation on different spatial scales. Although further research is required to determine the relative importance of different sources to the atmosphere locally and globally, this thesis has substantially advanced the state-of-the-science by i) demonstrating the significance of an air sampling artefact discussed as an uncertainty in the scientific literature over the past decade, ii) definitively ruling out volatilisation from environmental waters as a source of PFOA to air, iii) demonstrating transfer of PFAAs from seawater to air via sea spray aerosols and thus quantifying the environmental importance of this process, and iv) ultimately demonstrating that several types of sources of PFAAs impact the global atmosphere and thus PFAA contamination patterns in precipitation. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>
33

Avaliação da toxicidade de Agentes Extintores de Incêndios em misturas com Gasolina : contribuição para o estudo do incêndio no Terminal Petroquímico da Ultracargo (Santos, SP, Brasil) /

Daniel, Gabriela January 2018 (has links)
Orientador: Denis Moledo de Souza Abessa / Resumo: Em episódios de emergências ambientais, principalmente em incêndios causados por compostos inflamáveis, a extinção do fogo utilizando apenas água apresenta limitações. Como alternativa, nos últimos anos surgiram Agentes Extintores de Incêndios - AEI. Em 2015 no município de Santos, um grave incêndio ocorreu em tanques de gasolina e etanol. Para a extinção do fogo, foram utilizadas grandes quantidade de AEI que juntamente com os combustíveis dos tanques escorreram para os ecossistemas aquáticos adjacentes. Apesar do amplo uso desses compostos, há falta de informação sobre a composição e toxicidade das formulações, de modo que os Compostos Perfluorados (PFC) são relatados como o princípio ativo dessas substâncias. Assim, o objetivo foi avaliar os efeitos tóxicos dos diferentes AEI utilizados no incêndio e a Fração Solúvel da Gasolina (FSG) em testes isolados e em misturas. Os testes isolados foram realizados com Echinometra lucunter, Artemia sp. e Daphnia similis. Os testes com misturas foram realizados com Artemia sp. e D. similis utilizando os modelos conceituais de Concentração de Adição (CA) e Ação Independente (IA) com os desvios de Sinergismo, Antagonismo, DL (dependente da dose) e DR (dependente do químico). Para E. lucunter os resultados de CI50-42h foram de 0,11% para FSG e estiveram entre 0,0002 a 0,01% para AEI; para Artemia sp. os valores de CL50-48h foram de 0,11% para FSG e variaram entre 0,02 e 0,2% para AEI. Para D. similis as CE50-48h foram de 1,10% para FSG e ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In environmental emergencies, and special in those caused by flammable compounds, extinguishing fires by using only water has some limitations, requiring the use of Fire Suppression Agents (FSA). In 2015, a severe fire occurred in gasoline and ethanol tanks from a petrochemical plant located in the Santos city. To combat that fire, lots of FSA were diluted in estuarine and applied on the tanks resulting in an “effluent” containing fuels and FSAs. There is a lack of information about the toxicity of FSA’s commercial formulations, but the major active principles in these formulations are the Perfluorinated Compounds (PFCs). The aim of this study was evaluate the toxic effects of different FSAs and Gasoline Water Soluble Fraction (GWSF) in isolated and binary mixtures tests. The isolated analyses were performed with Echinometra lucunter, Artemia sp. and Daphnia similis. The mixture tests were performed with Artemia sp. and D. similis, using the conceptual models for CA and IA with deviations as synergism, antagonism, DL (Dose Level-dependent) and DR (Dose Ratio). The toxicity of isolated compounds to E. lucunter showed IC50-42h was 0.11% for GWSF and values ranging from 0.0002 to 0.01% for FSA; to Artemia sp. LC50-48h was 0.11% for GWSF and values ranging from 0.02 to 0.2% for FSA. To D. similis EC50-48h was 1.10% for GWSF and ranged from 0.03 to 0.3% for FSA. For mixture responses, all tests were significantly adjusted to CA (Concentration Addition) and IA (Independent Action) ... (Complete abstract click electronic access below) / Mestre
34

Perfluorinated compounds and trihalomethanes in drinking water sources of the Western Cape, South Africa

Booi, Xolelwa January 2013 (has links)
Thesis submitted in partial fulfilment of the requirements for the degree of MAGISTER TECHNOLOGIAE: CHEMICAL ENGINEERING in the FACULTY OF ENGINEERING at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2013 / This study focused on quantifying two types of internationally regulated contaminants found in drinking water: 1) Trihalomethanes (THMs) and 2) Perfluorinated compounds (PFCs). The first contaminants monitored were THMs, classified as a group of chemicals that are formed along with others during the disinfection of water using liquid chlorine, chlorine dioxide or chlorine gas. Hence, the resulting compounds are called disinfection by-products (DBPs). The disinfectant reacts with natural organic matter in water to form common THMs, which include chloroform (CHCl3 or CF), bromodichloromethane (CHCl2Br or BDCM), dibromochloromethane (CHClBr2 or DBCM) and bromoform (CHBr3 or BF), with chloroform being the most common in chlorinated water systems. The current study has focused on THMs for two primary reasons: 1) THMs have raised significant concern as a result of evidence that associate their presence in drinking water with potential adverse human health effects, including cancer and 2) the levels of THMs in drinking water post-treatment is not monitored regularly in South Africa and thus far, there is inadequate and limited information about their concentration levels for drinking water treatment plants (DWTPs) and distribution stations (DWDSs) of the Western Cape, South Africa before, distribution to various suburbs, including townships. THMs normally occur at higher levels than any other known DBPs and their presence in treated water is a representative of the occurrence of many other DBPs. THMs were quantified in chlorinated drinking water obtained from seven (7) DWTPs, namely; Atlantis, Blackheath, Faure, Brooklands, Steenbras, Voelvlei and Wemmershoek, and one DWDS in Plattekloof. This included determining THMs concentration in tap water collected from various suburbs including townships, to assist local authorities in obtaining information on their concentration and whether or not the presence of residual chlorine and organic matter on post-treatment results has increased THMs at the point of use. THM analysis was performed using liquid-liquid extraction/gas chromatography with electron capture detector (LLE-GC-ECD) analytical process according to the EPA method 501.2, which was used with minor modifications. The instrument operational conditions were as follows: Column → DB5-26, 30 mm, 0.53 mm, 1.0 μm df HP-1 (Agilent Technologies, USA); Carrier gas → Helium at a constant inlet pressure of 15 kPa; Make-up gas → 99.9% Nitrogen gas at 60 L/min; Injector temperature → 40°C; Oven temperature → 270°C and Detector temperature → 300°C. Since natural organic matter (NOM) in raw water is a precursor for THM formation, NOM analysis was performed as total organic carbon (TOC) using Spectroquant TOC test kits. Other drinking water quality parameters analysed were pH, residual free chlorine, conductivity and total dissolved solids (TDS). The average Total THM concentrations detected from seven of the DWTPs, including the DWDS, ranged from 26.52 μg/L (for Plattekloof) to 32.82 μg/L (for Brooklands), with the observed concentrations being comparable. The average chloroform concentrations were the highest in all the water samples, ranging from 11.74 μg/L (for Plattekloof) to 22.29 μg/L (for Voelvlei), while DBCM had the lowest concentration. The only DWTP that was not comparable with the seven DWTPs was Atlantis, with the highest average TTHM concentration of 83.48 μg/L and a chloroform concentration of 46.06 μg/L. From the tap water samples collected from 14 Western Cape suburbs, the average TTHM concentrations ranged from 5.30 ug/L (for Mandalay) to 13.12 μg/L (for Browns Farm, Philippi), and all these concentrations were lower than the TTHM concentrations detected in the water samples from the DWTP. Overall, the average total THM and individual THM species concentrations were below the recommended SANS 241:2011 and WHO drinking water guideline limits. This included the observed pH (6.39 to 7.73), residual free chlorine (0.22 to 1.06 mg/L), conductivity (121 to 444 μS/cm), TDS (93.93 to 344.35 mg/L) and TOC (0.38 to 1.20 mg/L). All these water quality parameters were within the specification limits stipulated in SANS 241. However, the average residual free chlorine concentration for Atlantis was very low (0.06 mg/L), which was below the WHO minimum residual free chlorine concentration guideline value of 0.2 mg/L for a distribution network – an indication that suggested the need for a re-chlorination station prior to distribution to households. Low chlorine content might result in the formation of unwanted biofilms in the distribution network, thus reducing the organoleptic properties of the water. Additionally, there was no direct link between several water quality parameters quantified (i.e. pH, TOC and water temperature) to TTHM formation. However, a high chlorine dose was observed to result directly in a higher concentration of chloroform in treated water prior to distribution. The second contaminants monitored were Perfluorinated compounds (PFCs), which are non-biodegradable, persistent and toxic organic chemicals known for their ability to contaminate environmental matrices, including drinking water sources. In recent years, many researchers considered it essential to identify and quantify PFC levels in drinking water worldwide with the main focus being on the two most abundant PFCs; namely Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS). Their toxic effects to human health, plants and wildlife were also evaluated, classifying them as possible carcinogens. We know from the literature reviewed that, although the presence of PFCs in drinking water has been documented worldwide, there is limited information about their presence specifically in South African drinking water sources, even about less studied PFCs such as Perfluoroheptanoic acid (PFHpA), Perfluorododecanoic acid (PFDoA), Perfluorononanoic acid (PFNA), Perfluoroundecanoic acid (PFUA), Perfluorodecanoic acid (PFDeA) and the well-known PFOA including PFOS. Although several other PFCs have been detected in water sources and reported in various studies, the USEPA only issued drinking water guideline limits for Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) of 400 ng/L and 200 ng/L, respectively, with no mention of the other PFCs. However, these PFCs have similar properties to those of PFOA and PFOS as they have been shown to impose similar detrimental health effects on human health. This study thus focused on the detection of PFCs in both raw and treated drinking water in the Western Cape DWTPs such as Atlantis, Blackheath, Faure, Brooklands, Steenbras, Voelvlei and Wemmershoek, and one DWDS in Plattekloof. Water samples (raw and treated water) used in this study for PFC analysis were collected in 2L polypropylene screw capped bottles. PFC analysis was performed in four sample batches for each location collected through the period of October to December 2012 (summer). PFCs were analysed in accordance with a modified EPA method 537, which entails solid phase extraction (SPE) followed by analysis using a liquid chromatography/tandem mass spectrometer (LC/MS/MS). The slight modification was with the water sample volume used for extraction, which was increased from 250 mL to 500 mL. The instrument used was an HPLC - Ultimate 3000 Dionex HPLC system and MS model - Amazon SL Ion Trap, with the following MS/MS operational conditions and Ion mode: MS Interface → ESI; Dry temp → 350C; Nebulizing pressure → 60 psi; Dry gas flow → 10 L/min; Ionisation mode → negative; capillary voltage → +4500V; End plate offset → −500V while the separation column was a Waters Sunfire C18, 5 μm, 4.6 × 150 mm column (Supplier: Waters, Dublin, Ireland) with an operational temperature of 30C. From the results obtained in this study, seven different PFCs (i.e. PFHpA, PFDoA, PFNA, PFUA, PFDeA, PFOA and PFOS), were detected in raw and treated water with PFOA and PFOS being the least detected PFCs as they were detected only in raw water (PFOA) from Faure, as well as raw and treated water (PFOS) from Brooklands. The highest concentration observed in treated water was for PFHpA, which was quantified at a maximum average concentration of 43.80 ng/L (Plattekloof). The maximum average concentrations of other PFCs detected were as follows: PFDoA - 4.415 ng/L for Faure raw water; PFNA - 2.922 ng/L for Plattekloof outlet; PFUA - 7.965 ng/L for Brooklands treated water and PFDeA - 2.744 ng/L for Faure raw water. Another observation from the results was that the concentration of the majority of the PFCs detected in treated water was higher than that quantified in raw water, suggesting possible contamination by materials used during water treatment. In conclusion, THMs detected in treated water from various DWTPs and one DWDS in the Western Cape met the required local and international drinking water quality guidelines, while the presence of PFOS, PFOA, PFHpA, PFDoA, PFNA, PFUA and PFDeA in treated water requires that local water professionals continue to monitor their presence to ensure that measures for their reduction are in place. Furthermore, the National standards (SANS 241) for municipal drinking water guidelines must be updated to include the monitoring of PFCs, including the lesser known and less studied PFCs such as PFHpA, PFDoA, PFNA, PFUA and PFDeA.
35

Lanthanide and transition metal complexes as building blocks for supramolecular functional materials / Complexes de lanthanides et de métaux de transition utilisés comme building blocks pour matériaux supramoléculaires fonnctionels

Arnedo-Sanchez, Leticia 08 December 2016 (has links)
Cette thèse porte sur les complexes de coordinations basés sur les métaux de transitions et les lanthanides en tant qu'éléments clés pour créer des matériaux fonctionnels. Précisément, des matériaux contenant des propriétés de détection, d'auto assemblage et optique ont été conçus et optimisés. En plus d'une brève introduction sur la photophysique, les gels supramoléculaires et les nanoparticules métalliques, un résumé sur les différents instruments et techniques employés pour ces travaux est inclus. Le chapitre 3 décrit la synthèse et la caractérisation de complexe de lanthanide anionique. Des techniques analytiques, tels que la spectroscopie d'émission ou la cristallographie à rayon X ont été employé pour caractériser ces différents complexes. Dans le chapitre 4, l'étude de complexes métalliques luminescents se focalise sur les complexes de métaux de transition, et plus précisément sur les complexes d'iridium(lll). Une famille de complexes d'iridium(lll) bi-cyclométallés neutres qui montre une intense émission rouge sous photo ou electro excitation est étudié. Le chapitre 5 présente la conception et le développement d'une nouvelle famille de gelators à faible poids moléculaire, basée sur des terpyridines perfluorés.La morphologie ainsi que les propriétés mécaniques et thermodynamique de ces metallogels sont étudiées. Le chapitre 6 présente une nouvelle sonde colorimétrique, composée de nanoparticules d'or fonctionnalisées avec des complexes de Zn aminoterpyridinique via des liaisons thiol est décrite pour la détection de pyrophosphate. / This thesis deals with coordination compounds based on transition metals and lanthanides as key components of functional materials. Besides a brief summary of photophysics, supramolecular gels and metal nanoparticles, an overview of the instruments and techniques employed in this work is included. This thesis is further divided into four chapters focused on optically active metalcomplexes (chapters 3 and 4), stimuli responsive metallogels (chapter 5) and functionalized nanomaterials for sensing applications (chapter 6). In chapter 3, the synthesis and characterization of anionic lanthanide complexes is reported. Analytical techniques, emission spectroscopy and X-ray crystallography were employed to characterize these complexes. ln chapter 4, the study of light emitting metal complexes is extended to transition metal complexes, in particular to iridium (lll) complexes. A family of neutral bis-cyclometallated iridium (lll) complexes that exhibit an intense red emission under photo- or electro-excitation is studied. ln chapter 5 the design and investigation of a new family of low molecular weight gelators based on perfluorinated terpyridines is reported. The morphology and mechanical and thermodynamical properties of these metallogels is studied. Chapter 6 studies the excellent cooperation between coordination compounds and nanomaterials to yield optical sensors. A new colorimetric sensor for pyrophosphate consisting of gold nanoparticles acting as reporting units functionalized with a thiol-modified aminoterpyridine-Zn complex is described.
36

Germania- and silica-based perfluorinated and non-fluorinated sol-gel sorbents for capillary microextraction in chromatographic analysis

Seyyal, Emre 06 April 2017 (has links)
Sample preparation is the most time-consuming and error-prone step in chemical analysis. Miniaturization and automation of the sample preparation equipment eliminating or reducing the use of hazardous organic solvents, online hyphenation of sample preparation with analytical instruments in a cost-effective way are important factors that need to be considered to design and implement innovative sample preparation techniques and strategies. Solid-phase microextraction (SPME) is a simple, environmentally benign technique well suited for hyphenation with analytical instruments. However, poor coating stability is a significant drawback of SPME employing conventionally prepared coatings. This shortcoming arises from the lack of chemical bonding between the sorbent coating and the substrate. Introduction of sol-gel coatings in SPME greatly improved thermal stability and solvent stability in SPME, by providing direct chemical bonding between substrate and the sol-gel coating. In traditional fiber format of SPME (where the sorbent coating is placed on the outer surface of an end-segment of the fiber) the coating remains vulnerable to mechanical damage. Capillary microextraction (CME), the capillary format of SPME (also known as in-tube SPME), allows to overcome this shortcoming by securing the sorbent coating on inner walls of the capillary. This dissertation focuses on the development and systematic investigation of novel silica- and germania-based perfluorinated and non-fluorinated sol-gel sorbents in the form of CME surface coatings: their preparation, material characterization, CME performance evaluation, preconcentration and recovery of various analytes including environmental pollutants. This research established that germania-based sol-gel sorbents are characterized by superior microextraction performance than analogous silica-based sorbents. This enhanced performance provided by germania-based sol-gel sorbents may be explained based on thermogravimetric analysis suggests that higher carbon loading on germania-based sol-gel sorbents. Germania-based phenyl- (Ph), phenethyl- (PhE), octyl- (C8), octadecyl- (C18) and cyclohexenylethyl- (ChE) ligand-containing sol-gel sorbents were prepared and various pollutants with aromatic rings (such as aromatic ketones, aldehydes and polycyclicaromatic hydrocarbons) were extracted and analyzed by CME-GC and CME-HPLC. It was observed that sol-gel sorbents containing aromatic ligands (PhE and Ph) provided superior microextraction performance for the analytes with aromatic ring(s) in their structure, than the sorbents with aliphatic ligands (C8 and C18). Investigation of sol-gel sorbents containing hydrophobic perfluorooctyl (PF-C8) and perfluorododecyl (PF-C12) ligands revealed that PF-C8 and PF-C12 sol-gel sorbents provided ~ 3 times higher microextraction efficiency (measure in terms of specific extraction, SE) than corresponding non-fluorinated counterparts, C8- and C12-, respectively. The synthesis and design of silica- and germania-based dual ligands sol-gel sorbents simultaneously providing superhydrophobicity and π-π interactions with analytes represent a significant accomplishment of this research. Such sorbents contained a PF-C12 and PhE ligands incorporated in sorbent chemical structure. In this case, perfluoro- group provided enhanced hydrophobic interaction and PhE group provided π-π interaction with the analytes. Combination of such interactions proved to be quite effective in the microextraction of alkylbenzenes and related compounds. Dual-ligand sol-gel sorbents with both equimolar and non-equimolar ligand concentrations were prepared. Experimentally it was established that sorbents with higher perfluorinated alkyl ligand concentrations had higher affinity for aliphatic hydrocarbons; however; when PhE concentration was higher, the dual-ligand sorbent showed enhanced affinity for aromatic compounds. The prepared sol-gel sorbents were characterized by less than 5% run-to-run RSD values, and also less than 5% capillary-to-capillary RSD values, which indicate that the sol-gel technique used in sorbent preparation was highly reproducible. The prepared sol-gel sorbents also showed that their performance does not deteriorate under aqueous saline matrix; therefore, it could be useful in the microextraction of pollutants from ocean water.
37

Mesoporous Adsorbents for Perfluorinated Compounds

Lotsi, Bertha 01 May 2020 (has links)
Effective adsorbents for polyfluorinated compounds (PFCs) were successfully prepared. And they were tested in the adsorption of perfluorooctanoic and perfluorooctanesulfonic acids. Bridged silsesquioxanes containing secondary and tertiary amino groups were synthesized by sol-gel condensation of bis[3-(trimethoxysilyl)propyl]amine and bis[3-(methylamino)propyl]-trimethoxysilane in acidic media with surfactants. Obtained materials are mesoporous with a high BET surface area. They combine high structural stability with a high concentration of surface amino groups serving as adsorption sites. Batch adsorption tests demonstrated their extremely high adsorption capacity on PFCs: in some experiments, it reached up to 88% of the adsorbent weight. Adsorption of PFCs changed the surfaces of the adsorbent nanoparticles from hydrophilic to hydrophobic thus providing their agglomeration and floatability. Column tests showed fast adsorption of PFCs even at high concentrations and high flow rates. Obtained results can be used in the development of an effective filtration device for clean-up of water contaminated by PFCs.
38

Occupational exposure to fluorinated ski wax

Nilsson, Helena January 2012 (has links)
Per- and polyfluorinated substances (PFAS) are used in the production of ski wax to reduce the friction between the snow and the ski. In this occupational study of ski wax technicians’ exposure to PFAS and particulate aerosol we have collected whole blood (wb) (n =94), air (n =84) and aerosol (n =159) samples at World Cup events from 2007-2011. We have analysed the blood, air and aerosol with respect to 13 perfluorocarboxylic acids (PFCAs), 4 perfluorosulfonic acids (PFSAs), 3 fluorotelomer alcohols (FTOHs), 3 fluorotelomer acids (FTCAs) and 3 unsaturated fluorotelomer acids (FTUCAs). Further, we assessed the exposure to 3 particulate aerosol fractions (inhalable, respirable and total aerosol) in air. In comparison to a general population, several of the PFCA blood levels are elevated in the technicians’, primarily  erfluorooctanoate (PFOA) and perfluorononate (PFNA) with concentrations up to 628 and 163 ng/mL wb, respectively. Further,  we detected FTUCAs and FTCAs in the blood, suggesting biotransformation of FTOHs to PFCAs. The metabolites 5:3 and 7:3 FTCA were detected in all blood samples at levels up to 6.1 and 3.9 ng/mL wb. Levels of perfluorohexadecanoic acid PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were detected in the technician’s blood at mean concentration up to 4.22 ng/mL wb and 4.25 ng/mL wb. The FTOH levels in air of the wax cabin during work ranged up to 997 000 ng/m3 (average=114 000 ng/m3 ) and PFOA up to 4 890 ng/m3 (average= 526 ng/m3 . FTOHs were not detected in aerosols but PFOA showed average levels of 12 000 ng/m3 (range=1 230- 46 900 ng/m3 ). The occupational exposure limit (OEL) of 2 mg/m3 was exceeded in 37% of the personal measurements with aerosol  concentrations up to 15 mg/m3 . Keywords : Perfluorinated, polyfluorinated, FIS, occupational exposure, ski wax,  iotransformation, metabolism, fluorotelomer alcohol, fluorotelomer acid, aerosol, dust, UPLC/MS-MS, GC/MS-MS
39

Nanočástice na bázi komplexů blokových kopolymerů s fluorovanými surfaktanty / Nanoparticles based on block copolymer complexes with fluorosurfactants

Škvarla, Juraj January 2012 (has links)
This thesis deals with (i) complex nanoaggregates of cationic perfluorinated surfactant N-(1,1,2,2- tetrahydroperfluorodecyl)pyridinium chloride and of double hydrophilic block polyanions poly(ethylene oxide)-b-poly(methacrylate) and poly(ethylene oxide)-b-poly((2-sulfamate-3- carboxylate)isoprene), and with (ii) mixed micelles of amphiphilic copolymer poly(ethylene oxide)- b-poly(e-caprolactone) and nonionic perfluorinated fluorosurfactant Zonyl FSN-100. The study was aimed at the characterization of the association behavior of the block copolymer-fluorosurfactant systems in aqueous solutions depending on the amount of the added surfactant, pH of the solvent and the structure of the copolymers.
40

Synthèse et caractérisation de matériaux polymères conducteurs protoniques pour membranes de pile à combustible / Synthesis of proton conducting polymer materials for fuel cell mambranes

Thiry, Xavier 05 February 2013 (has links)
Le travail reporté dans ce manuscrit concerne l’élaboration de matériaux conducteurs protoniques destinés à une application en tant que membrane de PEMFC. L’approche considérée, relativement récente dans ce domaine, consiste à élaborer des réseaux seminterpénétrés(semi-IPN). Pour ce faire, un polymère linéaire conducteur protonique (unPEEK sulfoné) a été associé à un réseau réticulé fluoré de type poly(aryl étherperfluorocyclobutane) (PFCB). Ces macromolécules sont obtenues par cyclodimérisationthermique de monomères bis et tris-trifluorovinyléther (TFVE). Différentes séries de semi-IPN ont été élaborées en faisant varier la nature du PFCB, le taux de réticulation, le procédéde mise en oeuvre et le taux de réseau incorporé au sPEEK. L’ensemble des résultats montrequ’il existe une composition pour laquelle les propriétés de conductivité, de gonflement et detenue mécanique sont optimales. Une membrane ayant une conductivité de 155 mS.cm-1 et ungonflement à l’eau deux fois inférieur à celui du sPEEK (dont la conductivité s’élève à127 mS.cm-1) a été obtenue grâce à un ajout de 10 % en masse en réseau fluoré. Par ailleurs,l’incorporation dans le réseau PFCB de monomères contenant des fonctions sulfoniques a étéenvisagée. Un travail important de chimie organique a permis d’obtenir des molécules bis-TFVE comportant des fonctions sulfonées protégées sous forme d’ester sulfonique. Lapolycondensation directe de ces molécules a permis la synthèse de polymères PFCB linéairesconducteurs protoniques d’une CEI préalablement déterminée. / This thesis deals with the conception of proton conducting materials used as PEMFCmembrane. The proposed approach is quite new in this application field and is based on thedevelopment of semi-interpenetrating networks (semi-IPN). A linear conducting polymer(sulfonated PEEK) was combined with a crosslinked fluorinated network, a poly(aryl etherperfluorocyclobutane) (PFCB). These macromolecules are obtained by thermalcyclodimerization of bis and tris trifluorovinylether monomers (TFVE). Different series ofsemi-IPN were prepared by changing the PFCB nature, the crosslinking degree, the synthesisprocess and the proportion of the network added to the sPEEK. The overall results show aspecific semi-IPN composition for which the conductivity, the swelling and mechanicalstrength properties are optimal. A membrane with a proton conductivity of 155 mS.cm-1 and alimited water swelling (50 % lower than for a sPEEK membrane which exhibits a protonconductivity of 127 mS.cm-1) is obtained by adding 10 wt-% of fluorinated network. Inaddition, the incorporation of sulfonated TFVE monomers into the network PFCB has beenconsidered. A significant effort in organic chemistry enabled the synthesis of bis-TFVEmolecules containing protected sulfonated functions in a sulfonate ester form. Linearconducting PFCB polymers with a predeterminated IEC were obtained by directcopolycondensation of these monomers.

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