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Aplica??o da parafina e do ?leo de linha?a como hidrofobizantes da vermiculita, para remo??o de derivados de ?leo diesel resentes em ?gua produzida sint?ticaSantos, Aline da Silva 29 October 2010 (has links)
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Previous issue date: 2010-10-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Produced water has lately aroused interest due to their high degree of salinity,
suspended oil particles, chemicals added in various manufacturing processes, heavy
metals and radioactivity sometimes. Along with oil and due to its high volume
production, water production is one of the pollutants of most concern in the process
of oil extraction. PAHs due to their ubiquity and their characteristics carcinogenic or
mutagenic and teratogenic even have attracted the attention of every scientific
society. Formed from the incomplete combustion of organic matter may be natural or
anthropogenic. Some materials have been researched with the goal of cleaning up
environmental matrices that may be contaminated by hydrocarbons. Among these
materials researched various clays have been employed, of which highlights the
vermiculite. The family of phyllosilicates, vermiculite for its potential and its high
hydrophobic surface area has been a tool widely used in the decontamination of
water in processes of oil spills. However, when it loses its capacity expanded
hydrophobic having the necessity of using a hidrofobizante to make it organophilic.
Among the numerous hidrofobizantes researched and used the linseed oil was the
pioneer. In this study sought to evaluate the capacity of removal of PAHs using the
vermiculite hydrofobized with linseed oil and wax also, for it was made use of the 24
full factorial design as the main tool for the experiments. We also evaluated the clay
grain size (-20 +48 and -48 +80 #), the percentage of hidrofobizante applied (5 and
10%) and salinity of the water produced synthesized in our laboratory (35,000 and
55,000 ppm). The molecular fluorescence spectroscopy due to its sensitivity and
speed was used to verify the adsorption capacity of clay, as well as gas
chromatography served as an auxiliary technique to identify and quantify the PAHs in
solution. In order to characterize the vermiculite was made use of X-ray fluorescence
and X-ray diffraction. The infrared and thermogravimetry were essential to note
hydrophobization and the amount of coating of clay. According to the fluorescence
analysis showed that the test 12 was the best result in about 98% adsorption of
fluorescent compounds, however the high salinity, the smallest particle size, the
highest percentage of hidrofobizante and the use of linseed oil showed greater
efficiency in the removal capacity of these hydrocarbons, in accordance with the
trend followed by the analysis of the major factors of the factorial design. To verify the
adsorption capacity of clay using a fixed volume of water produced synthetically,
used as the test base 12, at their respective levels and factors. Thus, it was observed
that after adding about 1 ? liters of water solution produced synthetically, about 300
times its volume in mass, the vermiculite was able to adsorb 80% of fluorescent
species present in solution / A ?gua produzida vem ultimamente despertando interesse devido ao seu
elevado grau de salinidade, part?culas de ?leo em suspens?o, produtos qu?micos
adicionados nos diversos processos de produ??o, metais pesados e algumas vezes
radioatividade. Juntamente com o petr?leo e devido ao seu elevado volume de
produ??o, a ?gua de produ??o ? um dos poluentes que mais preocupam no
processo de extra??o do ?leo. Os HPAs devido a sua ubiq?idade e suas
caracter?sticas carcinog?nicas/mutag?nicas e at? mesmo teratog?nicas v?m
chamando a aten??o de toda sociedade cient?fica. Formados a partir da combust?o
incompleta da mat?ria org?nica podem ser de origem natural ou antropog?nica.
Alguns materiais v?m sendo pesquisados com o objetivo de despoluir matrizes
ambientais que venham ser contaminadas por estes hidrocarbonetos. Dentre estes
materiais pesquisados v?rias argilas t?m sido empregadas, das quais se destaca a
vermiculita. Da fam?lia dos filossilicatos, a vermiculita por seu potencial hidrof?bico e
sua elevada ?rea superficial tem sido um utens?lio bastante utilizado na
descontamina??o de ?guas em processos de derramamento de ?leo. Contudo,
quando expandida esta perde sua capacidade hidrof?bica havendo a necessidade
do uso de um hidrofobizante para torn?-la organof?lica. Dentre os in?meros
hidrofobizantes pesquisados e utilizados o ?leo de linha?a foi o pioneiro. Neste
trabalho procurou-se avaliar a capacidade de remo??o de HPAs utilizando a
vermiculita hidrofobizada com ?leo de linha?a e tamb?m a parafina, para isto fez-se
uso do planejamento fatorial completo 24 como ferramenta principal para realiza??o
dos experimentos. Avaliou-se tamb?m a granulometria da argila (-20+48 e -48+80 #),
o percentual de hidrofobizante aplicado (5 e 10 %) e a salinidade da ?gua produzida
sintetizada em laborat?rio (35.000 e 55.000 ppm). A espectroscopia de fluoresc?ncia
molecular devido a sua sensibilidade e rapidez foi utilizada para verificar a
capacidade de adsor??o da argila, bem como a cromatografia gasosa serviu como
t?cnica auxiliar a fim de quantificar e identificar os HPAs presentes em solu??o. A fim
de caracterizar a vermiculita fez-se uso da fluoresc?ncia de raios X e difra??o de
raios X. O infravermelho e a termogravimetria foram essenciais para constatar a
hidrofobiza??o e a quantidade de recobrimento do argilomineral. De acordo com as
an?lises de fluoresc?ncia verificou-se que o ensaio 12 obteve o melhor resultado em
torno de 98 % de adsor??o dos compostos fluorescentes, contudo a elevada
salinidade, a menor granulometria, o maior percentual de hidrofobizante e o uso do
?leo de linha?a apresentaram maior efici?ncia na capacidade de remo??o destes
hidrocarbonetos, de acordo com a tend?ncia seguida pela an?lise dos fatores
principais do planejamento fatorial. Para verificar a capacidade de adsor??o da argila
utilizando um volume fixo de ?gua produzida sint?tica, usou-se como base o ensaio
12, nos seus respectivos n?veis e fatores. Deste modo, observou-se que ap?s a
adi??o de aproximadamente 1 ? litro de solu??o de ?gua produzida sint?tica, cerca
de 300 vezes o seu volume em massa, a vermiculita foi capaz de adsorver 80 % das
esp?cies fluorescentes presentes em solu??o
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Analyse des micropolluants organiques dans les sédiments et le biota (Perna viridis et Polymesoda erosa) de la baie de Jakarta et de la lagune de Segara Anakan, Indonésie / Organic micropollutants content in sediments and biotas (Polymesoda erosa and Perna viridis) from Jakarta Bay and Segara Anakan Lagoon, IndonesiaAzis, Muhammad Yudhistira 27 July 2016 (has links)
Les activités anthropiques ainsi que des phénomènes naturels sont à l’origine de risques avérés pour l’environnement. L'Indonésie est un pays archipélagique qui contient de nombreuses îles et régions côtières, où la croissance exponentielle des activités anthropiques a exposé l’environnement indonésien à de graves détériorations au cours des dernières décennies. Cette étude vise à explorer (qualitativement et quantitativement) les niveaux de contamination des sédiment de surface et du biote (P. Viridis, P. erosa,) au travers de deux sites atelier : la baie de Jakarta et la lagune de Segara Anakan (Java, Indonésie).Les méthodes de préparation des échantillon (extraction par solvant puis purification par chromatographie d’adsorption) suivies de l’analyse des extraits par GC/MS/MS ont été développées et qualifiées (linéarité, spécificité, reproductibilité).Les n-alcanes, HAP, PCBs et OCs sont détectés à des teneurs pouvant atteindre respectivement 1935 µg/kgPS, 916 µg/kg PS, 116,49 µg/kg PS, et 16,70 µg/kg PS, dans des sediments et 1739 µg/kg PS des HAPs et 24,79 µg/kg PS des OCs dans le biote. Les hydrocarbures, comme les HAPs sont majoritairement d’origine pétrolière (fuites, transport utilisation) même si la contribution pyrolytique est toujours présente.L’évaluation du risque environnemental a été réalisés pour les HAP, PCBS et et les OCs en utilisant les lignes directrices de la qualité des sédiments (RQS). Ces données peuvent servir de référence de base dans le cadre du programme de gestion intégrée des bassins versants impliquant la biodiversité, l'écologie de l'eau douce, et l'activité économique dans le domaine de cette étude. / Environmental problems can increase due to anthropogenic activities or natural phenomena. Indonesia is an archipelagic country that consists of many islands and coastal regions, where the growth of anthrophogenic and natural activities has exhibited severe environmental degradation in the past few decades. This study aims to explore (both qualitatively and quantitatively) the extent and sources of organic contaminants, i.e., n-alkanes in surface sediments; PAHs, PCBs and OCs in sediments and mussels, P. viridis from Jakarta Bay, North Jakarta, and P. erosa from the Segara Anakan Lagoon. Each protocol was continued with qualitative and quantitative analysis by GC-QQQ(triple-quadropole)/MS. Matrix interferences have been evaluated with proper samples with suitable yield of extraction and analysis. The n-alkanes, PAHs, PCBs and Organochlorin pesticides are detected in the highest levels in sediments, respectively 1935 µg/kg dw, 916 µg/kg dw, 116,49 µg/kg dw, and 16,70 µg/kg dw. In addition, the highest levels of PAHs (1739 µg/kg dw) and OCs levels (24,79 µg/kg dw) were found in biota. The source of hydrocarbons source, such the PAHs were generalelly petroleum source (transport utilization) although the pyrolytic are still present in sediments and biota. Environmental risk assessment from sediment quality guidelines (SQGs) were used to evaluate the probability risk in marine environments. Besides SQGs, sediments and mussels also in regard to the extent of the PAHs, PCBs and OCs (i.e. pp’-DDE) have been compared to other studies conducted at some polluted sites.
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Estudo multidisciplinar da evolução ambiental do Reservatório de Salto Grande, Americana, SP, a partir de análises multiproxies geoquímicos, de magnetismo ambiental e biológicos (Tecamebas) / Multidisciplinary study of the environmental evolution of the Salto Grande Reservoir, Americana, SP, from analysis of geochemical multiproxies, environmental magnetism and thecamoebiansMaria Laura Misailidis Lerena 03 October 2016 (has links)
A presente dissertação é um estudo da evolução ambiental do Reservatório de Salto Grande (RSG), Americana, SP, realizado a partir de análises granulométrica, geomagnética, geoquímica (especiação fósforo e carbono, elementos traço, compostos organoclorados e hidrocarbonetos aromáticos policíclicos) e biológica (tecamebas) de amostras de um testemunho sedimentar de 233 cm. Com base nos resultados obtidos, foi possível: 1) avaliar a toxicidade dos sedimentos, de acordo com os valores-guia de qualidade de sedimentos (VGQS) TEL e PEL, fator de enriquecimento (EF) e índice de geoacumulação (Igeo) e 2) identificar cinco fácies sedimentares, ao longo do testemunho. Fácies 1, situada na base do testemunho, é constituída por lama, com baixas concentrações de elementos traço, compostos organoclorados e HPAs, presença de material radicular e ausência de tecamebas. Essa sequência sedimentar pode ser atribuída às unidades de solos e sedimentos depositados na planície aluvial do Rio Atibaia e representa a fase Préreservatório. A partir de 177 cm de profundidade rumo ao topo, passam ocorrer mais quatro fácies, indicativas dos 65 anos de existência do RSG. A Fácies 2 (transição de solo e início do reservatório) caracteriza-se pela presença de lama, com tênue estratificação plana paralela e surgimento de tecamebas (Arcella gibbosa, A. megastoma, Difflugia corona, D. oblonga, D. gramen e Centropyxis discoide aculeata). Nessa fácies não foram detectados sedimentos contaminados, segundo VGQS. Contudo, foi constatado aumento expressivo de HPAs, provavelmente relacionado a queimadas ocorridas no entorno do reservatório. Fácies 3 (Reservatório) é marcada por sucessão de camadas de lama escura, intercaladas com lama clara, associadas às variações sazonais de produtividade do reservatório. Na porção final da Fácies 2 e toda a Fácies 3, ocorrem as maiores concentrações dos elementos traço (principalmente Cu, e Cr), parâmetros geomagnéticos, PCBs, DDT e HPAs, bem como o primeiro e maior declínio das populações de tecamebas. Nessa fácies 3 os VGQS indicam a presença de sedimentos fortemente contaminados. Fácies 4 continua a apresentar sucessão de camadas escuras e claras, contudo, as concentrações dos elementos traço, parâmetros geomagnéticos, PCBs, DDT e HPAs diminuem sensivelmente e os valores de densidade e diversidade das tecamebas aumentam. Valores de Cu diminuem mas, continuam expressivos, indicando sedimentos contaminados. As oscilações da concentração de Cu podem estar relacionadas ao uso de algicidas à base de CuSO4, que são utilizados no RSG para controlar a floração de cianobactérias e macrófitas. Fácies 5, correspondente ao período mais recente da história do RSG, caracteriza-se pela presença de lama preta, contaminada por Cu, pobre em tecamebas e baixas concentrações de DDT e HPAs. As curvas de evolução dos fluxos de fósforo inorgânico, Mn e Zn apresentaram forte similaridade com as curvas de crescimento demográfico da cidade de Americana e com as variações do regime de chuvas local. Estes resultados sugerem que as variações do aporte de nutrientes no reservatório encontram relação direta com as mudanças no escoamento de água pluvial na bacia de drenagem do Atibaia e com os influxos industriais e domésticos no RSG / This works presents an environmental evolution of the Reservatório de Salto Grande (RSG), Americana, accomplished through the grain-size, geochemical (phosphorous, carbon, trace elements, organochlorines and polycyclic aromatic hydrocarbons), and biological (thecamoebians) analyses from sample of a sediment core. Based on the results it was possible to: 1) evaluate the sediments according to the Sediment Quality Guideline Values for metals and associated (SQGV), enrichment factors, and geoaccumulation index and 2) identify five sedimentary facies through the core. Facies 1 located at the base of the core is composed of muddy sediments with low concentrations of trace elements, organochlorines and PAHs, presence of small trees roots and absence of thecamoebians. This sedimentary sequence could be attributed to soil units and sediments deposited in the alluvial basin of the Atibaia river and represents the pre-reservoir succession. From 177 cm through the top of the core more 4 facies are identified, all correlated with the time span of 65 years since the inundation of the RSG. Facies 2 (transition between soil portion and the reservoir inundation) is characterized by the presence of a homogeneous mud and a thin parallel planar stratification and by the appearance of thecamoebians (Arcella gibbosa, A. megastoma, Difflugia corona, D. oblonga, D. gramen, Centropyxis discoide aculeata). In this facies no contaminants were registered according to SQGV standards. But a high concentration of PAHs was detected possibly indicative of vegetation burning. Facies 3 (Reservoir) is marked by a succession of dark mud interleaved by whitish mud likely associated to seasonal variation of primary productivity in the reservoir. At the top portion of facies 2 and the whole extension of facies 3 were found the highest concentration of trace elements (Cu, and Cr), geomagnetic parameters, PCBs, DDT and PAHs, and the first and major decline of thecamoebians populations. In this facies SQGV are indicative of highly contaminated sediments. Facies 4 continuously shows the same succession of mud and the concentrations of trace elements, geomagnetic parameters, PCBs, DDT and PAHs show a sensitive decrease, and the values of richness and abundance of thecamoebians show an increase. Although the values of Cu diminish, they still remain expressive, indicative of sediment contamination. The oscillations of Cu concentrations may be related to the use of algaecides composed of CuSO4 in order to control populations of cyanobacteria and macrophytes. Facies 5 corresponds to the last centimeters of the core and to recent periods of the history of RSG, characterized by the presence of a black mud contaminated with Cu poor in species of thecamoebians and low concentrations of PCBs, DDT and PAHs. The curves of inorganic phosphorous, Mn and Zn showed a similar pattern to the curves of demographic growth and rain fall in the city of Americana. These results suggest that the variations of nutrients income are related to the change in water flow regimes in the Atibaia river watershed and to industrial and domestic input in the RSG
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Anthracroronene in Astrophysical Water-Ice AnalogsKorsmeyer, Julie 01 January 2019 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are the most abundant large organic molecules in space. They are thought to be the main contributor to the unidentified infrared (UIR) emission bands from the interstellar medium (ISM) for several reasons: UIR intensities correspond to carbon abundance, indicating the presence of a carbon-based molecule; UIRs are found in extremely harsh environments which means the source must be a stable molecule. The most important evidence is if the bands in mid-infrared (MIR) or 'fingerprint' region match those of PAHs. Through the infrared spectroscopy of matrix-isolated polycyclic aromatic hydrocarbons a compound's unique neutral and ionized vibrational modes can be identified. In this work, the PAH anthracoronene (AntCor, C36H18) is suspended in a matrix of water-ice, irradiated with ultraviolet (UV) light, and then analyzed using Fourier Transform Infrared (FTIR) spectroscopy. AntCor has not been studied in water ice before, and therefore the vibrational transition data collected (i.e. band positions and intensities) has been compared to coronene and anthracene, the parent molecules, and with theoretical predictions made using density functional theory. The data from this work will be incorporated into the NASA Ames PAH IR Database, where it will be applied to astronomical observations of the unidentified infrared emissions of the ISM, as well as observations of infrared absorption features in dense molecular clouds.
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Simplifying Sample Preparation using Fabric Phase Sorptive Extraction: Analysis of Trace Targeted Pollutant Residues in Environmental, Biological and Food SamplesMesa, Rodolfo 26 October 2017 (has links)
Sample preparation is an essential component of analytical methods in chemistry. It is not only necessary but also presents an opportunity to increase the effectiveness of the method significantly. There are various commercially available technologies for sample preparation, including numerous variations of LLE, SPE, and SPME. However, these technologies all present significant deficiencies, including the inability to extract directly from complex samples such as whole milk. Instrumental analysis has been improved greatly in the last two decades but still is not applicable to complex samples without sample preparation.
This work presents the theory of FPSE, including the synthesis of sol-gel sorbents, coating of FPSE cellulose substrates and the mechanism of retention. Original research data presented herein introduce a comprehensive view on possible applications of FPSE in forensic chemistry and otherwise. Five distinct FPSE-based methods were rigorously developed for analysis of targeted pollutant residues. These methods were validated and compare to leading methods published in peer-reviewed literature quite favorably. Four of the methods were coupled to HPLC-UV and designed for trace or ultra-trace analysis of PAHs, BTEX, substituted phenols and nitroaromatic explosives, respectively. An additional FPSE-based method was developed and validated for direct analysis of BPA and five estrogenic EDCs in commercially purchased whole milk. This latter was coupled to both HPLC-UV and HPLC(QQQ)-MS/MS.
The applicability of FPSE(PTHF) media was also tested for screening of aqueous samples and subsequent storage of analytes on the sorbent. My study included simultaneous extraction of a mixture of eight forensically significant compounds with various physicochemical properties and effective storage of each compound in frozen and ambient conditions for 32 weeks. These findings suggest that the storage ability of FPSE media can be extended as long as necessary, which is very significant in forensic laboratories where evidence often needs to be stored in a costly manner that may not be as effective in maintaining the chemical composition of the sample.
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Characterization of PAH-contaminated soils focusing on availability, chemical composition and biological effectsBergknut, Magnus January 2006 (has links)
The risks associated with a soil contaminated by polycyclic aromatic hydrocarbons (PAHs) are generally assessed by measuring individual PAHs in the soil and correlating the obtained amounts to known adverse biological effects of the PAHs. The validity of such a risk estimation is dependent on the presence of additional compounds, the availability of the compounds (including the PAHs), and the methods used to correlate the measured chemical data and biological effects. In the work underlying this thesis the availability, chemical composition and biological effects of PAHs in samples of soils from PAH-contaminated environments were examined. It can be concluded from the results presented in the included papers that the PAHs in the studied soils from industrial sites were not generally physically trapped in soil material, indicating that the availability of the PAHs was not restricted in this sense. However, the bioavailable fraction of the PAHs, as assessed by bioassays with the earthworm Eisenia Fetida, could not be assessed by a number of abiotic techniques (including: solid phase micro extraction, SPME; use of semi-permeable membrane devices, SPMDs; leaching with various solvent mixtures, leaching using additives, and sequential leaching) and it seems to be difficult to find a chemical method that can accurately assess the bioavailability of PAHs. Furthermore, it was shown that PAH-polluted samples may be extensively chemically characterized by GC-TOFMS using peak deconvolution, and over 900 components can be resolved in a single run. The chemical characterization also revealed that samples that appeared to be similar in terms of their PAH composition were heterogeneous in terms of their overall composition. Finally, single compounds from this large set of compounds, which correlated with different biological effects, could be identified using the multivariate technique partial least squares projections to latent structures (PLS). This indicates that PLS may provide a valid alternative to Effect Directed Analysis (EDA), an established method for finding single compounds that correlate to the toxicity of environmental samples. Thus, the instrumentation and data evaluation tools used in this thesis are clearly capable of providing a broad chemical characterization as well as linking the obtained chemical data to results from bioassays. However, the link between the chemical analyses and the biological tests could be improved as as an organic solvent that solubilised virtually all of the contaminants was used during the chemical analysis while the biological tests were performed in an aqueous solution with limited solubility for a number of compounds. Consequently the compounds probably have a different impact in the biological tests than their relative abundance in profiles obtained by standard chemical analyses suggests. The availability and bioavailability of contaminants in soil also has to be studied further, and such future studies should focus on the molecular interactions between the contaminants and different compartments of the soil. By doing so, detailed knowledge could be obtained which could be applied to a number of different contaminants and soil types. Such studies would generate the data needed for molecular-based modelling of availability and bioavailability, which would be a big step forward compared to current risk assessment practices.
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Evaluation Of Persistent Organic Pollutants (pops) In Balikesir Dam Lake SedimentsGokmen, Pinar 01 February 2011 (has links) (PDF)
In this study, the Persistent Organic Pollutants (POPs) specifically / 17
Organochlorine Pesticides (OCPs) and 19 Polycyclic Aromatic Hydrocarbons
(PAHs) were evaluated in the sediment samples of Balikesir (Ikizcetepeler) Dam
Lake. Sixteen sampling points were chosen for determination of concentrations of
OCPs and PAHs After ultrasonic bath extraction of the sediment samples GC-MS
was used as analytical tool. Extraction efficiencies changes from 63.8 to 87.4%
depending on the type of the POPs. Average OCP concentration was found in the
range of 3.33-379 µ / g/kg a, average PAH concentration was found in the range of
3.28-32.9 µ / g/kg. Pollution maps regarding OCP and PAH distributions were drawn
and the correlation between these two pollutant types was investigated. The quality
control (QC) and quality assurance tests were applied by the analysis of standard
reference materials (SRMs), surrogate standards and analysis replicates.
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Predictive Modeling of Organic Pollutant Leaching and Transport Behavior at the Lysimeter and Field ScalesAmankwah, Edward Akwasi 15 December 2007 (has links) (PDF)
Soil and groundwater pollution has become a global issue since the advent of industrialization and mechanized agriculture. Some contaminants such as PAHs may persist in the subsurface for decades and centuries. In a bid to address these issues, protection of groundwater must be based on the quantification of potential threats to pollution at the subsurface which is often inaccessible. Risk assessment of groundwater pollution may however be strongly supported by applying process-based simulation models, which turn out to be particularly helpful with regard to long-term predictions, which cannot be undertaken by experiments. Such reliable predictions, however, can only be achieved if the used modeling tool is known to be applicable. The aim of this work was threefold. First, a source strength function was developed to describe the leaching behavior of point source organic contaminants and thereby acting as a time-dependent upper boundary condition for transport models. For general application of these functions dimensionless numbers known as Damköhler numbers were used to characterize the reaction of the pollutants with the solid matrix. Two functions were derived and have been incorporated into an Excel worksheet to act as a practical aid in the quantification of leaching behavior of organic contaminant in seepage water prognoses. Second, the process based model tool SMART, which is well validated for laboratory scale data, was applied to lysimeter scale data from two research centres, FZJ (Jülich) and GSF (München) for long term predictions. Results from pure forward model runs show a fairly good correlation with the measured data. Finally, the derived source term functions in combination with the SMART model were used to assess groundwater vulnerability beneath a typical landfill at Kwabenya in Ghana. The predicted breakthrough time after leaking from the landfill was more than 200 years considering the operational time of the facility (30 years). Considering contaminant degradation, the landfill would therefore not cause groundwater pollution under the simulated scenarios and the SMART model can be used to establish waste acceptance criteria for organic contaminants in the landfill at Kwabenya / Seit dem Beginn der Industrialisierung und der mechanisierten Landwirtschaft wurde die Boden- und Grundwasserverschmutzung zu einem weltweiten Problem. Einige Schadstoffe wie z. B. PAK können für Jahrzehnte oder Jahrhunderte im Untergrund bestehen. Um diese Probleme behandeln zu können, muss der Schutz des Grundwassers basierend auf der Quantifizierung potentieller Gefährdungen des zumeist unzugänglichen Untergrundes erfolgen. Risikoabschätzungen von Grundwasserverschmutzungen können jedoch durch die Anwendung prozess-basierter Simulationsmodelle erheblich unterstützt werden, die sich besonders im Hinblick auf Langzeitvorhersagen als hilfreich erweisen und nicht experimentell ermittelbar sind. Derart zuverlässige Vorhersagen können jedoch nur erhalten werden, wenn das verwendete Modellierwerkzeug als anwendbar bekannt ist. Das Ziel dieser Arbeit bestand aus drei Teilen. Erstens wurde eine Quellstärke-funktion entwickelt, die das Ausbreitungsverhalten organischer Schadstoffe aus einer Punktquelle beschreibt und dadurch als zeitabhängige obere Randbedingung bei Transportmodellen dienen kann. Im Hinblick auf die allgemeine Anwendbarkeit dieser Funktion werden als Damköhler-Zahlen bekannte, dimensionslose Zahlen verwendet, um die Reaktion von Schadstoffen mit Feststoffen zu charakterisieren. Zwei Funktionen wurden abgeleitet und in ein Excel-Arbeitsblatt eingefügt, das ein praktisches Hilfsmittel bei der Quantifizierung des Freisetzungsverhaltens organischer Schadstoffe im Rahmen der Sickerwasserprognose darstellt. Der zweite Teil dieser Arbeit beinhaltet die Anwendung des prozessbasierten und mittels Laborexperimenten validierten Modellwerkzeugs SMART für Langzeitprognosen auf der Lysimeterskala anhand von Daten zweier Forschungszentren, FZJ (Jülich) und GSF (München). Ergebnisse reiner Vorwärtsmodellierungsläufe zeigten gute Übereinstimmungen mit den gemessenen Daten. Im dritten Teil wurden die erhaltenen Quellstärkefunktionen in Kombination mit dem SMART-Modell eingesetzt, um das Grundwassergefährdungspotential unter einer typischen Deponie in Kwabenya, Ghana, einzuschätzen. Die vorhergesagten Durchbruchszeiten nach einer Leckage in der Deponie betragen über 200 Jahre bei einer Betriebszeit von 30 Jahren. Unter Berücksichtigung des Schadstoffabbaus verursacht die Deponie somit keine Grundwasserverunreinigung im Rahmen der simulierten Szenarien und das SMART-Modell kann verwendet werden, um Schadstoffgrenzwerte für organische Schadstoffe in der Deponie in Kwabenya festzulegen.
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Novel sol-gel titania-based hybrid organic-inorganic coatings for on-line capillary microextraction coupled to high-performance liquid chromatographyKim, Tae-Young 01 June 2006 (has links)
Novel sol-gel titania-poly(dimethylsiloxane) (TiO2-PDMS) and titania-silica-N-(triethoxysilylpropyl)-O-polyethylene oxide urethane (TiO2-SiO2-TESP-PEO) coatings were developed for capillary microextraction (CME) to perform on-line preconcentration and HPLC analysis of trace impurities in aqueous samples. Due to chemical inertness of titania, effective covalent binding of a suitable organic ligand to its surface is difficult via conventional surface modification methods. In this research, sol-gel chemistry was employed to chemically bind hydroxy-terminated poly(dimethylsiloxane) (PDMS) and N-(triethoxysilylpropyl)-O-polyethylene oxide urethane (TESP-PEO) to sol-gel titania and sol-gel titania-silica network, respectively. A method is presented describing in situ preparation of the titania-based sol-gel PDMS and TESP-PEO coatings and their immobilization on the inner surface of a fused-silica microextraction capillary.
To perform on-line CME-HPLC, the sol-gel TiO2-PDMS or TiO2-SiO2-TESP-PEO capillarywas installed in the HPLC injection port as an external sampling loop, and a conventionalHPLC separation column was used for the liquid chromatographic separation. The sol-gel TiO2-PDMS-coated microextraction capillary was used for on-line CME-HPLC analysis of non-polar and moderately polar analytes, and the sol-gel coatings showed excellent pH (1-13), and solvent (acetonitrile and methanol) stabilities under elevated temperatures (150 C) over analogous non-sol-gel silica-based coatings. Extraction of highly polar analytes, especially from aqueous phases is not an easy task. However, the sol-gel TiO2-SiO2-TESP-PEO-coated capillaries showed excellent capability of extracting underivatized highly polar analytes from aqueous samples.
This opens the possibility to employ sol-gel titania-based polar coatings for solvent-free extraction and trace analysis of target analytes in environmental and biomedical matrices. To our knowledge, this is the first research on the use of sol-gel titania (or titania-silica)-based organic-inorganic materials as a sorbent in capillary microextraction. The newly developed sol-gel titania (or titania-silica)-based organic-inorganic hybrid extraction media provides an effective solution to coupling CME with HPLC (CME-HPLC), and this can be expected to become a powerful analytical tool in environmental investigations, proteomic research, early disease diagnosis and biomarker research. Being a combination of a highly efficient solvent free sample preconcentration technique (CME) and a powerful separation method (HPLC), CME-HPLC poses to become a key analytical tool in solving complex chemical, environmental, and biomedical problems involving complex matrices.
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The Environmental Effects of Coal FiresGarrison, Trent 01 January 2015 (has links)
There are thousands of subterranean coal fires in the world that, because of incomplete combustion, emit a wide variety of volatile and semivolatile organic compounds to the atmosphere, water, and soil at concentrations that could pose health risks to humans and wildlife. The main goals of this study were to (1) review methods that are used to characterize physical and chemical characteristics of coal-fire sites, (2) determine relationships between gas emissions and physical and chemical characteristics of coal-fire sites, using a combination of regression and multivariate statistical methods, and (3) determine the concentrations of volatile and semivolatile organic compounds in water and soil at two coal-fire sites in eastern Kentucky. More specifically:
The objective of Chapter 1 was to review past works and list technologies used over time. Eight years of coal-fire collection technologies were reviewed. A variety of methods and technologies were identified. Qualitative and quantitative preferences were noted.
The objective of Chapter 2 was to identify and list uncontrolled coal-fire variables. These variables include complete/incomplete combustion; fire temperature and size; distance to fire; relative humidity and moisture in the system; geology, geochemistry, and age of coal; condition of the mine, sampling time of day; sampling equipment differences; and human error. A secondary objective of this chapter was to determine which coal-fire gases have strong relationships by using the principal component analysis (PCA) software JMP. The strongest relationship was between CO and H2S. Temperature and CH4 were also important. This indicates that incomplete combustion and polynuclear aromatic hydrocarbon (PAH) formation are likely occurring, setting the stage for Chapter 3.
The objective of Chapter 3 was to identify and define the extent of soil and water hydrocarbon contamination at the Truman Shepherd and Lotts Creek coal fires in eastern Kentucky. No groundwater contamination was detected at either location. Soil contamination was found at both, but was much higher at Lotts Creek, potentially because of sorption onto soil organic matter (which is reduced at Truman Shepherd by an excavation attempt) and other physicochemical mechanisms. Soil contamination was localized to relatively small areas around coal-fire vents.
Based on the results, future studies should consider: Attempting to duplicate these results in other geologic regions Quantifying greenhouse gas emissions from coal fires to consider their contribution to climate change. Coal-fired power plants are regulated, but coal fires, which produce many more harmful gases, are not Determining the feasibility of an oxygen-injection system to engender more complete combustion, therefore possibly reducing harmful gases Determining the feasibility of electricity production from coal fires Adopting a consistent federal coal-fire policy
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