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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.
1

Contaminant issues in production and application of biochar

Buss, Wolfram January 2016 (has links)
For widespread use of biochar in agriculture and horticulture, it must be ensured that application will neither adversely affect soil and plants, nor exceed legislated contaminant concentrations. The most relevant groups of contaminants in biochar are potentially toxic elements (PTEs), polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOC). In this thesis, the concentrations of these groups of contaminants were analysed in 90 different biochars produced by slow pyrolysis. Subsequently, the concentrations were compared to legislation/guideline threshold values and linked to production conditions. The risk these contaminants pose to plant growth was also assessed, to give recommendations on production of safe biochar. PTEs can neither be formed nor destroyed, which means their presence in biochar is predominantly determined by feedstock type. However, significant levels of Cr, Fe and Ni were introduced into biochar from the furnace steel, whilst PTEs with low boiling points, such as As, Cd and Zn, partially evaporated during pyrolysis. PTEs were not responsible for phytotoxic effects observed for PTE-rich biochars despite biochar’s exceedance of available and total PTE threshold values for soil and soil amendments. Although initial tests were promising, the risk that PTE-rich biochars as amendment for soil and growing media pose, needs further investigation. The PAH concentration in biochar was markedly reduced by increasing carrier gas flow rate, and the type of feedstock also influenced the PAH content. However, there was no clear dependence of pyrolysis temperature on PAH concentrations, which was attributed to PAHs being increasingly formed and evaporated at higher pyrolysis temperatures. Ultimately, condensation of pyrolysis vapours and deposition on biochar was identified as the main risk for biochar contamination with PAHs, as this resulted in elevated concentrations of high-risk, higher molecular weight PAHs. Weaknesses in the pyrolysis unit design, such as cold zones, resulted in elevated concentrations of VOCs, as well as PAHs, in biochar. Comparing concentrations and phytotoxic potential of both compound groups, it was concluded that observed toxic effects were much more likely caused by VOCs in biochars containing both contaminants. Overall, formation of VOCs and PAHs cannot be prevented, but their presence in biochar resulting from retention and deposition can be minimised.
2

Method development and Validation for the determination of selected Polycyclic Aromatic Hydrocarbons (PAHs) in water by Solid Phase Extraction and High Performance Liquid Chromatography

Xoliswa, Madlanga 12 February 2014 (has links)
Polycyclic Aromatic Hydrocarbons (PAHs) are one of the pollutants in the environment. They are organic compounds that consist of more than one aromatic ring (Kanchanamayoon & Tatrahun 2008). Due to less information forthcoming regarding the levels of PAHs in Vaal area, this study is to evaluate the levels of PAHs in the rivers around Vaal Triangle. Three river sites such as Vaal, Barrage and Klip Rivers were selected to investigate the concentration of polycyclic aromatic hydrocarbons in water. Validation of an analytical method is the process by which it is established by laboratory studies, that the performance characteristics of the method meet the requirements for the intended analytical application. (Stockl et al 2009). The validation parameters tested were, linearity detection limit of quantitation, sensitivity, accuracy, specificity, selectivity, robustness and ruggedness. PAHs can be determined using High Performance Liquid Chromatography (HPLC) which is a technique for separation, identification and quantification of components in a mixture. The following ten compounds were identified and quantified with a HPLC: naphthalene, acenaphthylene, phenanthrene, anthracene, fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h) anthracene and indeno(1,2,3-cd)pyrene. The linear calibration ranges from 0.1-5ppm.The linearity ranges between 0.9993-0.9999.Three reversed sorbent phases (Strata-X, MFC18 and C18) were tested for PAH retention efficiency. An optimised reverse solid phase extraction (SPE) method was used after conditioning the sorbent to extract and collect compounds of polycyclic aromatic hydrocarbons (PAHs) in river water samples. LC18 sorbent showed good recoveries after extracting PAHs standard mixture of 1 mg/l. The best performing eluting solvent was acetonitrile and very good percentage recoveries that ranged from 70% to over 100 % were obtained for eight compounds. Poor recoveries were also obtained for phenanthrene (61%) and benzo(b)fluoranthene (48%). The standard deviation ranged from 0.01 to 0.05 and the detection limits ranging from 0.01 – 0.17 mg/l were obtained. Average concentration ranges of PAHs identified within the study area were: phenanthrene (0.02 – 0.42 mg/l); anthracene (0.37 – 0.39 mg/l), fluoranthene (0.11 – 0.15 mg/l); benzo(b)fluoranthene (0.09 mg/l) and indeno(1,2,3-cd)pyrene (0.26 mg/l). However, naphthalene, acenaphthylene, benzo(k)fluoranthene, benzo(a)pyrene and dibenzo(a,h)anthracene were not detected.
3

Quantification of PAHs and PCBs in eThekwini aquatic systems, using chemical and biological analysis / Natasha Lee Vogt

Vogt, Natasha Lee January 2014 (has links)
Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are common contaminants of sediment, soils and biological tissues. These compounds pose a significant risk to biological and ecosystem health and functioning due to these compounds being mutagenic, carcinogenic and are known to disrupt the endocrine system. The bioaccumulation and biomagnification potential that these compounds possess mean that they are capable of affecting the entire food chain and are not limited to the organisms that are directly in contact with the compounds Even though there has been an increase in the attention on identifying the presence and impacts that these compounds may have in South Africa, the level of attention is lower than what it is in other countries around the world. Although South Africa has guidelines in place for other pollutants, such as metals, there are no such guidelines in place to monitor PAHs and PCBs.. Industries are known to release both PAHs and PCBs, mainly from incomplete burning processes and the release of oils and fuels in the case of PAHs, and from heat transfer fluids in the case of PCBs. Durban Bay and surrounding areas of eThekwini, KwaZulu-Natal are highly industrialised with many aquatic systems, in which these contaminants are likely to deposit. The aim of this research was to determine the concentrations of these compounds by means of chemical analysis and additionally biological analysis, using the H4IIE-luc bioassay and compare these levels to international guideline levels. It was found that the concentrations of the 23 analysed PAHs were 6.5–3 235.6 ng.g-1 and the concentration of the PCBs analysed were 0–113.83 ng.g-1. Many sites were found to be in exceedance of the guideline limits, particularly in the harbour. Toxic equivalency factors (TEF) were used to gauge the toxic equivalency (TEQ) of the PAHs and PCBs that were found. The TEQs were generally low, and were below any guideline levels. The assay revealed the extract containing the PCBs had a bioassay equivalence (BEQ) of 0–93.54 pgTCDDeq. g-1 and the extract containing the PAHs of 0–776.08 pgTCDD-eq.g-1. With a proportion of the sites exceeding guideline limits. The BEQ results were two to three orders of magnitude greater than the TEQs calculated from the concentrations determined by the instrumental analysis, however, followed a similar trend. Additionally chemical analysis was not performed on a full suite of compounds that are able to elicit a response from the cells, which could be a reason why the BEQ and TEQ did not follow a similar trend among some of the samples. It would have been more beneficial to have performed chemical analysis on the 16 priority PAHs (as determined by the United States Environmental Protection Agency), the dioxin-like PCBs and polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDFs) which are all capable of eliciting a response from the cells and have TEF values. The areas that were most affected by contamination of these compounds was the harbour and surrounding canals, and there was point source contamination along the Umhlatuzana, Umbilo, and Amanzimnyana Rivers. All dl-PCBs should be chemically analysed at all the sample areas, as these cause adverse effects to biota. In addition to this, biota should be sampled to determine concentrations of the compounds to determine bioavailability and the degree of bioaccumulation in the food chain. Utilising biomarkers it would be possible to determine stresses of fish. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
4

Quantification of PAHs and PCBs in eThekwini aquatic systems, using chemical and biological analysis / Natasha Lee Vogt

Vogt, Natasha Lee January 2014 (has links)
Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are common contaminants of sediment, soils and biological tissues. These compounds pose a significant risk to biological and ecosystem health and functioning due to these compounds being mutagenic, carcinogenic and are known to disrupt the endocrine system. The bioaccumulation and biomagnification potential that these compounds possess mean that they are capable of affecting the entire food chain and are not limited to the organisms that are directly in contact with the compounds Even though there has been an increase in the attention on identifying the presence and impacts that these compounds may have in South Africa, the level of attention is lower than what it is in other countries around the world. Although South Africa has guidelines in place for other pollutants, such as metals, there are no such guidelines in place to monitor PAHs and PCBs.. Industries are known to release both PAHs and PCBs, mainly from incomplete burning processes and the release of oils and fuels in the case of PAHs, and from heat transfer fluids in the case of PCBs. Durban Bay and surrounding areas of eThekwini, KwaZulu-Natal are highly industrialised with many aquatic systems, in which these contaminants are likely to deposit. The aim of this research was to determine the concentrations of these compounds by means of chemical analysis and additionally biological analysis, using the H4IIE-luc bioassay and compare these levels to international guideline levels. It was found that the concentrations of the 23 analysed PAHs were 6.5–3 235.6 ng.g-1 and the concentration of the PCBs analysed were 0–113.83 ng.g-1. Many sites were found to be in exceedance of the guideline limits, particularly in the harbour. Toxic equivalency factors (TEF) were used to gauge the toxic equivalency (TEQ) of the PAHs and PCBs that were found. The TEQs were generally low, and were below any guideline levels. The assay revealed the extract containing the PCBs had a bioassay equivalence (BEQ) of 0–93.54 pgTCDDeq. g-1 and the extract containing the PAHs of 0–776.08 pgTCDD-eq.g-1. With a proportion of the sites exceeding guideline limits. The BEQ results were two to three orders of magnitude greater than the TEQs calculated from the concentrations determined by the instrumental analysis, however, followed a similar trend. Additionally chemical analysis was not performed on a full suite of compounds that are able to elicit a response from the cells, which could be a reason why the BEQ and TEQ did not follow a similar trend among some of the samples. It would have been more beneficial to have performed chemical analysis on the 16 priority PAHs (as determined by the United States Environmental Protection Agency), the dioxin-like PCBs and polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDFs) which are all capable of eliciting a response from the cells and have TEF values. The areas that were most affected by contamination of these compounds was the harbour and surrounding canals, and there was point source contamination along the Umhlatuzana, Umbilo, and Amanzimnyana Rivers. All dl-PCBs should be chemically analysed at all the sample areas, as these cause adverse effects to biota. In addition to this, biota should be sampled to determine concentrations of the compounds to determine bioavailability and the degree of bioaccumulation in the food chain. Utilising biomarkers it would be possible to determine stresses of fish. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
5

Polycyclic Aromatic Hydrocarbons In Urban Soils From West Yorkshire, UK. Investigation into Abundances, Sources and Determining Factors

Hamed, Heiam A.M. January 2018 (has links)
This study aims to determine the concentration of 16 Polycyclic Aromatic Hydrocarbons (PAHs) in urban soils from West Yorkshire in order to determine what the factors are controlling their distribution and abundances. Although PAHs have been reported before from soils and sediments, the majority of these studies have come from China, sometimes with contrasting results, which emphasises the need to obtain equivalent data from other areas. Therefore this work provides the first measurements of their type from the area studied. Soil samples were collected from one hundred sites across an area from Bradford to Leeds on two occasions, one in autumn and one in the following summer. The soil samples were analyzed by X-ray diffraction and all found to have similar mineralogical composition, which was mainly silica and calcite. Trials using iodine as a marker for PAHs showed there were notable interactions between the minerals and PAHs, with calcium carbonate absorbing PAHs much more than silica. There is a negative correlation between the soil organic content (determined by loss on ignition) and PAHs, which confirms the PAH-mineral interaction. Gas chromatography with mass spectrometry (GC-MS) using targeted selected ion monitoring was used to determine and quantify PAHs in the one hundred soil samples with the aid of PAH external standards. The results showed highest concentrations of total PAHs in the same sample from Leeds from the autumn (1,525 ng/g) and in the summer (1,768 ng/g). In Bradford there was only moderate pollution of PAHs, the maximum being 122 ng/g. However the majority of data from Bradford showed lower levels of pollution in both summer and autumn. On the basis of prior published information, the ratio of these compounds has been used to help in identifying sources. In the samples collected from Bradford in both seasons and Leeds in autumn the PAH pollution originated from pyrogenic, biomass and petroleum combustion, however in the summer the source appeared more to be from a petrogenic source. These ratios in the samples which were collected from the area between Bradford and Leeds implied pyrogenic, biomass source of pollution in the autumn, but in the summer another source of organic compounds was indicated namely petroleum combustion. When the locations were resampled nine months later, after taking into account within-site variability, there was a strong indication that the PAH concentrations were higher. This might have been due to a seasonal effect, but when a further (third) subsample was taken at a later date it showed a further increase in PAH level which suggests the effect is accumulative rather than seasonal. The results were analysed using Principal Component Analysis (PCA) to determine whether the type of road had an effect on the concentration of the 16 PAHs compounds, but it was concluded that there was no such effect. However, the distance from the soil sample to the nearest road did have an effect on the concentration of the 16 PAH compounds, especially in soil samples having the shortest distance to the road. Traffic volume was also tested and found to influence the PAH concentrations. It is notable that, comparing the groupings from autumn with those from summer by cluster analyses, they largely had the same compounds grouping together in both cases; only two compounds differed at all in where they occurred in the clusters, with consistent patterns of grouping found for the other compounds. These analyses indicate that PAH compounds behave in a consistent way amongst groups of PAH compounds. The grouping of PAHs appears linked to their sources rather than number of rings or molecular weight. / Libyan Government and Embassy
6

Etude en microcosmes de l'effet du ray-grass et de ses exsudats racinaires sur la dissipation des HAP et les communautés bactériennes dégradantes / Study in microcosms of effects of ryegrass and roots exudates on PAH dissipation and degrading bacterial communities

Louvel, Brice 18 October 2010 (has links)
Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques, ubiquistes, potentiellement toxiques et cancérigènes. Dans les sols, la dégradation des HAP est principalement due à l'activité microbienne. Certaines études ont montré que la biodégradation des HAP pouvait être augmentée dans la rhizosphère des plantes où le nombre et l'activité microbienne sont stimulés, grâce aux exsudats racinaires. Cependant les bénéfices des plantes ne sont pas toujours observés, et les exsudats pourraient aussi modifier la biodisponibilité des HAP. Les objectifs de ce travail ont été de mieux comprendre ces interactions sol-plante-microorganismes qui conditionnent le devenir des HAP dans la rhizosphère en suivant notamment (i) les bactéries possédant les gènes codant une HAP-dioxygènase, (ii) les espèces bactériennes impliquées dans la dégradation du phénanthrène, et (iii) la disponibilité et la biodégradation des HAP dans des terres industrielles historiquement contaminées.Les expériences ont été conduites dans des dispositifs à compartiments, lesquels permettent une diffusion des exsudats racinaires dans le sol tout en retenant physiquement les racines, puis en microcosmes avec un ajout d'exsudats racinaires naturels produits à partir d'une culture hydroponique de ray-grass (Lolium perenne, L). Les expériences ont été réalisées dans un premier temps avec du sable en ajoutant du phénanthrène (PHE) et un inoculum bactérien issu d'un sol d'une ancienne cokerie puis directement avec des sols historiquement contaminés en HAP. Les nombres de copies de gènes codant pour l'ADNr 16S et pour des HAP-dioxygènases ont été quantifiés par PCR en temps réel pour estimer la proportion de bactéries dégradantes. Les structures des communautés ont été comparées par électrophorèses (TTGE). En plus de l'analyse des 16 HAP totaux, une extraction non exhaustive des HAP a été réalisée à la cyclodextrine pour en estimer la disponibilité. L'utilisation de la méthode SIP (stable isotope probing) avec du 13C-phénanthrène a permis d'identifier les bactéries directement impliqués sa dégradation dans un sol historiquement contaminé. Les expériences en dispositifs à compartiments ont confirmé que la dissipation du phénanthrène est plus importante lorsque la distance aux racines est plus faible, et montrent que le nombre de copies de gène 16S et de gène de HAP-dioxygénase varie avec l'âge des plantes et du temps de contact des compartiments latéraux avec le tapis racinaire. Mais elles montrent aussi que la dissipation du phénanthrène n'est pas plus importante dans les pots plantés, tandis que dans les expériences en microcosmes une inhibition de la dissipation du PHE a même été observée en présence d'exsudats. La présence d'exsudats racinaires a profondément modifié la structure des communautés dégradant les HAP, et l'expérience SIP a permis d'identifier les bactéries directement impliquées dans la dégradation du 13C-phénanthrène et de montrer qu'elles étaient différentes en présence ou non d'exsudats. En présence d'exsudats, la proportion des bactéries dégradantes dans la population totale est passée de 1 % dans la terre d'origine et dans les traitements sans exsudats à plus de 10 %. Même si les exsudats racinaires ralentissent la dissipation du phénanthrène, en fournissant une source de carbone plus facilement métabolisable, ils ont augmenté la quantité de HAP extractibles à la cyclodextrine dans deux des trois sols historiquement contaminés, suggérant un effet de ceux-ci sur la biodisponibilité des HAP / Polycyclic Aromatic Hydrocarbons (PAH) are organics pollutants, ubiquitous, toxics and potentially carcinogenic. In soil, PAH degradation is mainly attributed to microbial organism. Several studies have thus reported enhanced PAH degradation in soil in the presence of plants. Rhizospheric soil increase the number et the activity of microorganisms in soil by the release of roots exudates. However, bene?cial effects of plants in the remediation are not always observed and roots exudates could be limited PAH biodegradation. The object of this study was to investigate the fate of PAHs in rhizosphere, following (i) the PAH-dioxygenase genes DNA to quantify the PAH-degrading bacteria, (ii) species implicated in phenanthrene biodegradation, and (iii) PAH availability and biodegradation from industrial soils.Different experimental devices have been designed to study detailed processes in the rhizosphere. First is a compartments devices were a nylon mesh permits diffusion of plant soluble substances towards the adjacent root free compartment as a rhizosphere. Secondly microcosms were enriched with natural roots exudates from hydroponic culture of ray-grass (Lolium perenne L.). In first time, experiments were conducted using sand and bacterial inoculum from an industrially PAH-contaminated soil and then directly with a soil historically contaminated by PAH. The Real-Time PCR quantification of 16S rRNA gene copy and of functional PAH-RHD? genes permitted to assess the proportion of a degrading bacteria. Bacterial community structure was approached from Temporal Thermal Gradient gel Electrophoresis (TTGE) fingerprinting, and bands sequencing. Nonexhaustive cyclodextrin-based extraction technique provided a estimate of the ?labile? or available pool of PAH in soil. Use of stable isotope probing (SIP) technique with [13C]phenanthrene allowed a bacterial identification of directly implicated in industrial soil.The presence of exudates modified microbial community of PAH-degrading bacteria. SIP experiment showed that 13C-labelled PHE-degrading bacteria was different depending on the exudates input. Many species having to degrade phenanthrene were able to use exudates. Presence of root exudates increased the proportion of PAH-RHD? genes compared to the bulk soil at the beginning and in microcosms without exudates (respectively 10% and 1 %). However, phenanthene dissipation in sand or soil were weaker with root exudates and aged PAH concentrations has not shifted during incubation time. Nevertheless, the root exudates increased the PAH labile fraction extract with cyclodextrin solution into two in three soils historically contaminated
7

Ionic Liquid-Mediated Sol-Gel Sorbents for Capillary Microextraction and Challenges in Glass Microfabrication

Shearrow, Anne M 18 May 2009 (has links)
Three ionic liquids (ILs), trihexyltetradecylphosphonium tetrafluoroborate (TTPT), N-butyl-4-methylpyridinium tetrafluoroborate (BMPT), and 1-methyl-3- octylimidazolium tetrafluoroborate (MOIC), were utilized to prepare sol- gel sorbent coatings. Non-polar polydimethylsiloxane (PDMS) and polar poly(ethylene glycol) (PEG), poly(tetrahydrofuran) (PolyTHF) and bis[(3-methyldimethoxy-silyl)propyl] polypropylene oxide (BMPO) polymers were employed to develop novel ionic liquidmediated sol- gel hybrid organic- inorganic sorbents. The novel sorbents were first tested as coatings for capillary microextraction off-line hyphenated to gas chromatography. To gain an understanding of the role of the ionic liquids in the sol-gel process, the preconcentration abilities of these novel coatings were investigated for several classes of compounds utilizing CME-GC. This was accomplished by comparing GC peak areas of a series of analytes extracted on the ionic liquid mediated sol-gel CME coatings with that of analogous peak areas obtained on sol- gel coatings prepared without the ionic liquid. The morphology of these coatings was compared using scanning electron microscopy (SEM) imaging data. Overall, the ionic liquid-mediated sol- gel coatings had more porous morphologies than the sol-gel coatings prepared without ionic liquid. The PDMS andBMPO sol-gel coatings prepared with ionic liquid in the sol solution provided enhanced extraction sensitivity reflected in higher preconcentration effects and lower detection limits than the sol- gel coatings prepared without the ionic liquid. The polar IL-mediated BMPO sol- gel sorbent was further investigated by exploring the extraction profile and thermal stability of these coatings. A further application of ionic liquid-mediated sol-gel sorbents could be as stationary phases in a microchip-based separation system. Towards this goal, microfluidic channels were fabricated in glass substrates using microelectromechanical engineering. Spiral and serpentine channels were etched in Pyrex and fused silica wafers using wet and deep reactive ion etching (DRIE) techniques. Microfabrication protocols such as the use of hard mask and etching times were investigated for both techniques. DRIE produced microfluidic channels that had an etch quality that was superior to wet etched channels. Thus, the ultimate microchip-based separation system should by fabricated using DRIE.
8

Extração em fase sólida magnética : nova abordagem na determinação de hidrocarbonetos policíclicos aromáticos (HPA) em água produzida por cromatografia líquida de alta eficiência / Magnetic solid phase extraction : new approach to determining polycyclic aromatic hydrocarbons (PAH) in water produced by high performance liquid chromatography

Caetano, Vinícius Crispim Lima de Barros 30 November 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The oil and gas industry produces huge amounts of produced water (PW), a complex effluent. This product is one of the main constituents of polycyclic aromatic hydrocarbons (PAH), which exhibit high toxicity. Therefore, this study aims at developing and validating a method for determining PAH (Benz(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, and Dibenzo (a,h)anthracene) in PW by using magnetic solid phase extraction (MSPE) and high-performance liquid chromatography with fluorescence detector. We synthesized three new adsorbents: FeCt (with ferric chloride and water rich in natural organic matter); FeCc (with ferric chloride, distilled water, and coconut husk), and FeSt (with ferric sulfate and water rich in natural organic matter). The x-ray diffraction and infrared spectroscopy confirmed obtaining the hybrid materials. The best extraction conditions were obtained by using ultrasonic cleaning as a mixing mechanism with time set to 2.5 minutes for adsorption and 2.5 minutes for desorption, using 10 mL of ethyl acetate as an extractor and 20 mg of hybrid FeSt; the values of PAH recovery varied from 84.3 to 92.3 %. The capacity of reusing the material was assessed and the results exhibited a great recovery with up to 4 cycles of adsorption/desorption. The methodology we propose was applied to two PW samples. The recovery values for samples PWW1 (produced water at well 1) enriched with 100μg L-1 were of 81 – 104%, without the presence of B(a)P standard. As for the PAH concentrations in the sample, they varied from 0.63 to 1.66 μg L-1 for PWW1 from 0.54 to 1.62 μg L-1 for PWW2 (produced water at well 2). The validation of the method was performed for the following parameters: linearity, which exhibits a correlation coefficient (r) above 0.9943 within the interval of 0.5 - 25 μg L-1 ; accuracy and precision, with recovery values between 98.2 – 108.9 %, and coefficient of variation 0.64 – 6.72 % for the concentration levels of 3.8 and 15 μg L-1 (n=3), respectively. LODs varied from 0.012 and 0.02 μg L-1 and LOQs, from 0.036 to 0.06 μg L-1. / A indústria de petróleo e gás produz grandes quantidades de água produzida (AP), que é um efluente complexo, sendo que um dos seus principais constituintes são os Hidrocarbonetos Policíclicos Aromáticos (HPA), os quais apresentam elevada toxicidade. Assim, o presente trabalho tem por objetivo desenvolver e validar um método de determinação de HPA (Benzo(a)Antraceno, Benzo(b)Fluoranteno, Benzo(k)Fluoranteno, Benzo(a)Pireno e Dibenzo(ah)Antraceno) em AP utilizando a extração em fase sólida magnética (MSPE) e cromatografia líquida de alta eficiência com detector de fluorescência. Foram sintetizados três novos adsorventes FeCt (com cloreto férrico e água com alto teor de MON), FeCc (com cloreto férrico, água destilada e bagaço de coco) e FeSt (com sulfato férrico e água com alto teor de MON). A difração de raios X e a espectroscopia de infravermelho confirmaram a obtenção dos materiais híbridos. As melhores condições de extração foram obtidas em banho de ultrassom como mecanismo de agitação, com tempo estipulado em 2,5 min para a adsorção e 2,5 min para a dessorção, utilizando 10 mL de acetato de etila como extrator e 20 mg do híbrido FeSt. Os valores de recuperação dos HPA variaram de 84,3 – 92,3 %. A capacidade de reutilização do material foi avaliada e os resultados apresentaram ótima recuperação com até 4 ciclos de adsorção/dessorção. A metodologia proposta foi aplicada em duas amostras de AP e os valores de recuperação para a amostra de APP1 (água produzida poço 1), enriquecida com 100 μg L-1, foram de 81 – 104 %, sem a presença do padrão do B(a)P, e a concentração dos HPA na amostra variou de 0,63 – 1,66 μg L-1 para o APP1, e de 0,54 – 1,62 μg L-1 para o APP2 (água produzida poço 2). A validação do método foi realizada para os parâmetros: linearidade, com o coeficiente de correlação (r) acima de 0,9943 no intervalo de 0,5 - 25 μg L-1; exatidão e precisão, com valores de recuperação entre 98,2 - 108,9 % e coeficiente de variação 0,64 - 6,72 % para os níveis de concentração 3, 8 e 15 μg L-1 (n=3), respectivamente. Os limites de detecção (LD) variaram entre 0,012 a 0,02 μg L-1 e os limites de quantificação (LQ) entre 0,036 a 0,06 μg L-1. / São Cristóvão, SE
9

Molecularly imprinted polymers for detection of volatile organics associated with fuel combustion

Ngwanya, Olwethu January 2018 (has links)
Magister Scientiae - MSc (Chemistry) / Pollutants such as polycyclic aromatic hydrocarbons (PAHs) are known for their toxic effects which may lead to the cause of degenerative diseases in both humans and animals. PAHs are widespread in the environment, and may be found in water, food, automotive industry and petrochemical industries to name but a few sources. Literature reports have highlighted industrial workplace exposure to PAHs as a leading cause for development of cancer in workers. Particularly, workers in the petrochemical industry are adversely affected and the incidence of skin and lung cancer in this population group is high. The United States of America in its guidelines developed by environmental protection agency (EPA) has identified 18 PAHs as priority pollutants. Among these are anthracene, benzo[a]pyrene and pyrene which have been selected as the focal point of this study due to their significance in the petrochemical industry. Due to the carcinogenic and mutagenic properties reported in literature for certain PAHs, there have been monitoring procedures taken in most countries around the world. The commonly used analytical methods for the detection of PAHs from industrial samples are high performance liquid chromatography (HPLC) coupled to fluorescence detection, membrane filtration, ozonation and reverse osmosis. Analysis of PAHs from the petrochemical industry is typically performed by HPLC method as well as sono-degredation in the presence of oxygen and hydrogen peroxide.
10

Avaliação dos níveis de concentração e identificação de fontes de hidrocarbonetos na Bacia do Alto Iguaçu: estudo de caso pós derrame acidental de óleo na refinaria Presidente Getúlio Vargas

Gallota, Fabiana Dias Costa 02 May 2016 (has links)
Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2016-05-02T17:58:54Z No. of bitstreams: 1 GALLOTTA_30_06_14.pdf: 62695484 bytes, checksum: 33335ee3affc2bcffb11fc10caf9ae3f (MD5) / Made available in DSpace on 2016-05-02T17:58:54Z (GMT). No. of bitstreams: 1 GALLOTTA_30_06_14.pdf: 62695484 bytes, checksum: 33335ee3affc2bcffb11fc10caf9ae3f (MD5) / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências-Geoquímica. Niterói, RJ / Os hidrocarbonetos presentes no ambiente consistem em misturas complexas de compostos derivados de múltiplas fontes. Os combustíveis fósseis representam a principal contribuição, devido à taxa e escala espacial, em que o petróleo tem sido usado como fonte de energia e matéria-prima para a indústria química. O objetivo deste estudo foi avaliar os níveis de concentração e identificar fontes de hidrocarbonetos na Bacia do Alto Iguaçu e, em especial, na área de influência da Refinaria Presidente Getúlio Vargas (REPAR). Além dos fatores de poluição crônica, a área de estudo foi alvo de um derrame acidental de petróleo em julho de 2000. Diversos indicadores em diferentes compartimentos ambientais (água superficial, sedimento, solo e água subterrânea) foram avaliados na fase pós-derrame e no monitoramento ambiental ao longo de várias campanhas por mais de uma década. Os esforços de avaliação foram concentrados nos seguintes indicadores: os nalcanos, os alcanos isoprenoides, os hidrocarbonetos policíclicos aromáticos (HPA), os biomarcadores de petróleo e ainda o total de hidrocarbonetos de petróleo (THP). Os resultados identificaram como principal aporte de matéria orgânica para as águas superficiais dos rios Barigüi e Iguaçu, os fluxos materiais originados em região a montante do acidente, refletindo a contribuição antropogênica crônica da cidade de Curitiba. Em 2007 e 2008, as concentrações de THP e HPA nas águas superficiais e sedimentos dos rios Barigüi e Iguaçu refletem uma expressiva melhoria nas condições desses rios em relação a 2000. Na área interna da refinaria (Ponto Zero), observou-se uma nítida diminuição (atenuação) natural das concentrações de THP no solo em todas as profundidades dos perfis amostrados ao longo do tempo nos Banhados 1 e 4 e, em particular, uma diminuição importante das concentrações entre 2004 e 2007. Para a identificação das fontes de hidrocarbonetos foram utilizadas razões diagnósticas e quimiometria. As razões diagnósticas calculadas a partir de concentrações de HPA sugeriram que, na maioria dos sedimentos dos Rios Barigüi e Iguaçu coletados nas campanhas de 2000 e 2001, a fonte petrogênica é a principal. Somente na estação a montante do acidente no Rio Barigüi, a fonte pirolítica predominou nestas duas campanhas. As razões diagnósticas que apresentaram maior eficiência na identificação de fontes de hidrocarbonetos nos sedimentos dos rios Barigüi e Iguaçu foram: ΣC1-Fenantrenos/Fenantreno; e (ΣHPA parentais de 3-6 anéis)/(Σ5 séries de HPA alquilados). A identificação de fontes através de razões diagnósticas calculadas a partir de áreas e alturas de picos cromatográficos demonstrou sua aplicabilidade verificando a relação entre os compostos encontrados em amostras de solo da área interna da refinaria com a amostra de petróleo derramado no acidente, após quase uma década da ocorrência do vazamento. A identificação de fontes através método de quimiométrico baseado na análise de componentes principais (ACP) de seções pré-processadas e combinadas dos Cromatogramas de Íons Selecionados (CIS) mostrou que as amostras mais contaminadas estão na área interna da refinaria. Essas amostras apresentam um padrão de distribuição petrogênica e diferentes graus de intemperismo. As amostras da área externa à refinaria (Guajuvira, General Lúcio e Balsa Nova) são menos ou não contaminadas e/ou contém uma mistura de contribuições diagenéticas, pirolíticas e petrogênicas onde predominam diferentes proporções. Os locais mais distantes da atividade industrial (Balsa Nova) contem, como esperado, os níveis mais baixos de contaminação por HPA. Os resultados de biomarcadores demonstraram que não há evidências para concluir que as amostras da área externa à refinaria e o óleo Cusiana vazado tenham a mesma origem. Os resultados ao longo dos rios Barigüi e Iguaçu e do Ponto Zero demonstraram que as ações de emergência para a contenção do óleo foram adequadas para os rios, e que a contaminação decorrente do derrame ficou predominantemente contida no Ponto Zero e diminuiu significativamente após uma década. / Hydrocarbons present in the environment consist of complex mixtures of compounds derived from multiple sources. The main contribution lies on fossil fuel inputs due to the rate and spatial scale by which petroleum has been used as an energy source and chemical feedstock. The aim of this study was to assess the concentration levels and identify sources of hydrocarbons in the Upper Iguaçu Watershed and, in particular, in the area of influence of the President Getulio Vargas Refinery (REPAR). In addition to the factors of chronic pollution, the study area was the scenario of an acute accidental oil spill in July 2000. Numerous indicators in different environmental compartments (surface water, sediment, soil and groundwater) were assessed in the post spill phase and during the environmental monitoring programs over the course of several campaigns for more than a decade. Assessment efforts were concentrated on the following indicators: n-alkanes, alkanes isoprenoids, polycyclic aromatic hydrocarbons (PAH), petroleum biomarkers and total petroleum hydrocarbons (TPH). The results identified as the main contribution of organic matter to surface waters of the Barigüi and Iguaçu Rivers the materials flows originated in the region upstream of the accident, reflecting chronic anthropogenic contribution of the city of Curitiba. In 2007 and 2008, the TPH and PAH concentrations in surface waters and sediments of the Barigüi and Iguaçu Rivers revealed a significant improvement in the conditions of these rivers when compared with 2000. Inside the refinery area (Point Zero), it was observed a clear natural decrease (attenuation) of the concentrations of TPH in the soil at all depths sampled over time in Marshes 1 and 4 and, in particular, an important decrease of concentrations between 2004 and 2007. Diagnostic ratios and chemometrics were used to identity hydrocarbon sources. The diagnostic ratios calculated from the concentrations of PAH suggested that, in the majority of sediments from the Barigüi and Iguaçu Rivers collected in 2000 and 2001 campaigns, the main source is petrogenic. Only in the station upstream the accident in the Barigüi River, the pyrolytic source predominated in these two campaigns. The diagnostic ratios that presented higher efficiency in identifying sources of hydrocarbons in sediments of the Barigüi and Iguaçu Rivers were: ΣC1- Phenantrenes/Phenanthrene; and (Σ3-6 rings parental PAH)/(Σ5 alkylated PAH series). The source identification through diagnostic ratios calculated from heights and areas of chromatographic peaks demonstrated its applicability establishing a relationship between the compounds found in soil samples of the internal area of the refinery and the sample of the oil spilled in the accident, after nearly a decade of occurrence of the spillage. The source identification through chemometric method based on principal components analysis (PCA) of preprocessed and combined sections of Selected Ion Chromatograms (SIC) showed that the most contaminated samples are inside the refinery area. These samples present a petrogenic pattern and different weathering degrees. Samples from outside the refinery area (Guajuvira, General Lúcio e Balsa Nova) are either less or not contaminated, and/or contain mixtures of diagenetic, pyrogenic and petrogenic inputs where different proportions predominate. The locations farthest away from industrial activity (Balsa Nova) contain, as expected, the lowest levels of PAH contamination. The biomarkers results do not show any evidences to conclude positive matches between the samples from outside the refinery area and the spilled Cusiana oil. The results along Barigüi and Iguaçu rivers and Point Zero demonstrated that emergency actions to contain the oil were appropriate for the rivers, and that the contamination resulting from the spill was mostly contained in the Point Zero and decreased significantly after one decade

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