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Multi-Proxy Approach on Black Carbon Characterization and Combustion Products Source Discrimination in Environmental MediaKuo, Li-Jung 2009 December 1900 (has links)
Environmental applications of pyrogenic carbon, aka black carbon (BC), have
been hampered due to the poor characterization and quantification of environmental BC.
This dissertation was dedicated to the better characterization of environmental
char/charcoal BC (char-BC), the most heterogeneous and the less identifiable group in
the BC continuum. The analytical approach developed for char-BC was further
incorporated with other BC methods in environmental samples for a comprehensive
assessment of combustion-derived carbon inputs in different environmental systems.
The present study firstly evaluated the feasibility of using levoglucosan, a marker
derived from cellulose/hemocellulose combustion, to characterize and quantify char-BC
in the environment. Levoglucosan was found exclusively in BC materials derived from
biomass combustion albeit in highly variable yields across different char-BC. A further
examination of synthetic chars showed that temperature is the most influential factor
affecting levoglucosan yield in char. Notably, levoglucosan was only detectable in low
temperature char samples (150-350 degrees C), regardless of plant species. These results demonstrated that levoglucosan could serve as a good qualitative indicator for the
presence of char produced under low temperature conditions in soil, sediments, and
aerosols.
Results of lignin analysis on the synthetic chars further reveal that combustion can
greatly decrease the yield of the eight major lignin phenols with no lignin phenols
detected in any synthetic char produced at greater than or equal to 400 degrees C. The values of all lignin parameters
show significant shifts with increasing combustion severity (temperature and/or
duration), indicating that thermal alteration is an important abiotic lignin degradation
process. Hence the input of char-BC in the environments represents a terrestrial organic
matter source with highly altered lignin signatures.
Finally, a multi-proxy approach, including elemental (soot-BC) and molecular
(levoglucosan, polycyclic aromatic hydrocarbons (PAHs), and lignin oxidation products)
proxies, was adopted to investigate the centennial-scale temporal distribution of
combustion products in four sediment cores from Puget Sound basins, WA. The
observed temporal trends of soot-BC and combustion PAHs fluxes reflect the evolution
of energy consumption and the positive effects of environmental regulations. The
distinct temporal patterns of soot and PAHs among cores demonstrate that urbanization is
a crucial factor controlling the inputs of combustion byproducts to the environment. On
the other hand, the trends of levoglucosan may be more relevant to the climate oscillation
and thus show a regional distribution pattern. Our results demonstrate that environmental
loading of combustion byproducts is a complex function of urbanization and land use,
fuel usage, combustion technology, environmental policies, and climate changes.
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Analysis of Fuel Performance and Exhaust Emissions of Ultra-low Sulphur Diesel Blending with BiofuelsChen, Kung-Fu 17 February 2005 (has links)
This study investigated the fuel properties, engine performances, and emissions of two biodiesels and diesel. The fuels examined were D100 (ultra-low sulfur diesel), B20 (20% palm biodiesel +80% ultra-low sulfur diesel) and B100 (palm biodiesel).
The fuel properties analysis results showed that the benefits of biodiesel were high cetane value, extremely low sulfur and aromatic contents, and good lubricity. While the defects of biodiesel were high pour point. The particulates emitted from the burning of D100, B100, B20 were mainly fine particulates, also known as young aerosols. Particles smaller than 2.5 µm easily enter the trachea and bronchus via the upper respiratory tract, finally deposit on the alveolus, which could cause severe injury to human health.
The emission of soluble organic fraction (SOF) from diesel engine using D100, B100 and B20 were 23.2%, 19.9% and 20.2%, respectively. The SOF of D100 is slightly higher than B100 and B20. It suggested that adding biodiesel into diesel can decrease SOF and thus reduce the potential danger to human health.
The original total PAHs concentration of tail gas emitted from engines using D100, B100 and B20 were 241, 50.6 and 98.8 µg/m3, respectively. Adding 20% biodiesel into D100 could reduce 59.0% of PAHs emission. Moreover, the original total BaPeq concentration of tail gas emitted from diesel engines using D100, B100 and B20 were 0.714, 0.509 and 0.570 µg/m3, respectively. Adding 20% biodiesel into D100 could also reduce 20.2% of total BaPeq emission. Hence, adding biodiesel into diesel can effectively reduce the emission of PAHs and the potential danger to human health.
The emission factors of carbonyl compounds from diesel engines using D100, B100 and B20 were 395, 1,170 and 326 mg/BHP-hr, respectively. carbonyl compounds of B100 were obviously higher than D100 and B20. The results indicated that using pure palm biodiesel in diesel engine can increased the emission of carbonyl compounds. However, adding 20% biodiesel into D100 can effectively reduce 17.5% of carbonyl compounds emission.
Keyword: ultra-low sulfur diesel, palm biodiesel, fuel properties¡BThe emission of soluble organic fraction (SOF)¡BPAHs¡Bcarbonyl compounds¡C
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Distribution and Flux of the Polycyclic Aromatic Hydrocarbons of Kao-ping Estuary SystemWu, Sih-pei 06 February 2006 (has links)
Water, suspended particle and sediment samples from Kao-ping estuary were collected and measured for concentrations of polycyclic aromatic hydrocarbons (PAHs) during March 2004 and April 2005. In addition, sediments from neighboring coastal area were also analyzed to estimate distribution, transportation and possible sources of PAHs. Total PAH concentrations varied from 33.0 to 910 ng/g dry weight (dw) in coastal sediments, and diagnostic ratios reflect a mixed sources of petrogenic and pyrolytic inputs. Due to the contribution of Kao-ping River, spatial distribution of PAH concentrations at coastal sediments near river mouth varied dramatically. Results of hierachical cluster analysis showed that PAH concentration distribution was influenced by Kao-ping canyon, and biogenic source might be the major PAH source for offshore sediments. Total PAH concentrations in river sediment varied from 63.0 to 720 ng/g dw. Higher concentration was measured between the Water Main pipe and Shuang-yuan Bridge, and possible sources were from both petrogenic and pyrolytic sources. Sediment of Dung-gang harbour had highest concentration, 28,000ng/g dw, in this study, which was contributed from petrogenic sources due to its intensive boating activities. Except fluorene and phenanthrene in harbour sediments, individual PAH concentrations of other sediments are lower or near the Effect Range Low value, concentrations might lead to possible adverse effects upon organism.
Total PAH concentrations varied from 5.0 to 82.0 ng/L in suspended particulate phase and from 5.5ng/L to 46.0ng/L in dissolved phase, respectively. Most of high molecular weight PAH concentrations (>5-ring PAHs) in dissolved phase were below method detection limits. The partition coefficients¡]Koc¡^values of PAHs were 1 to 2 orders higher than predicted values. It might be attributed to soot particles which have extremely high sorption capacities. Correlation coefficients between total PAH concentrations in sediments versus total organic carbon¡]TOC¡^ and fine particle content¡]<63£gm%¡^were significant ¡]R=0.575, 0.800, 0.851 and 0.657, P<0.01¡^. In addition, PAHs in suspended particulate phase and dissolved phase were also significantly correlated to particulate organic carbon¡]POC¡^ and dissolved organic carbon¡]DOC¡^, respectively.
The distribution of calculated PAH concentrations from organic carbon was higher in surface water than bottom water. Unlike salinity, there was no decreasing or increasing trend of these concentrations among river samples. It is possible that contamination was not come from upstream, but from estuary area where plume was lifted and diffused upstream by neat seawater. The flux in Wan-da Bridge was higher than downstream estuary area that might be due to PAH concentrations reduction by sedimentation or degradation.
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Stable carbon isotope ratio of polycyclic aromatic hydrocarbons (PAHs) in the environment: validation of isolation and stable carbon isotope analysis methodsKim, Moon Koo 15 November 2004 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, toxic contaminants that are released to the environment from various petrogenic and pyrogenic sources. In an effort to more clearly identify and trace sources of PAHs in the environment, purification and compound specific isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs. Development of the method included improving accuracy and precision of the isotopic measurement by producing highly pure extracts using various chromatographic techniques. The method was refined by improving compound separations using purification techniques and high resolution chromatographic columns. The purification method consists of alumina/silica gel column chromatography, gel permeation chromatography and thin layer chromatography. The mean recovery of PAHs after the purification procedure was approximately 80 %. Sample purities after purification were verified by GC/FID and full scan mass spectrometry. To better resolve peaks and provide more accurate stable carbon isotope measurements, various gas chromatographic conditions were evaluated. The precision of the method ranged between 0.08 and 0.43 . The analytical protocols were evaluated to confirm compositional and stable isotopic integrity during purification and stable isotopic analysis. To confirm the utility of the purification and isotope analysis methods, various environmental samples from marine, land and lacustrine environments were analyzed. The isolates were analyzed for the composition and the stable carbon isotope ratios of PAHs. The stable carbon isotope ratio was measured by GC/IRMS and the results, along with quantitative compound compositions, were used to characterize and identify the contaminant sources. The sources of the PAHs in the study areas were differentiated by PAH molecular ratios and confirmed by stable carbon isotope ratios. This study confirms that compound specific isotope analysis of pollutants by GC/IRMS can be used to identify PAH sources in environmental samples. The study also confirms that the purification and stable carbon isotope analysis methods that were developed can be used to accurately measure the stable carbon isotope ratios of PAHs in environmental samples for the purpose of source identification. GC/IRMS measurement of stable isotopic compositions can be an effective fingerprinting method when used in conjunction with traditional molecular composition methods.
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Studies of the characteristics of atmospheric polycyclic aromatic hydrocarbons in Kaohsiung city and at rural sites in Central TaiwanWang, Hsin-Kai 12 May 2008 (has links)
The high-volume air sampling (PS-1) and micro-orifice uniformdeposit impactor (MOUDI) were used to measure the concentrations ofpolycyclic aromatic hydrocarbons (PAHs) in the atmosphere for fourseasons at Tuzo-Yin and Hsiung-Kong site in Kaohsiung city, in the airof a agricultural residue open burning area in Jhu-Shan and Sin-Gang siteduring the rice straw non-burning and burning periods, together with thesize distributions. Also, the receptor model was employed to determinethe potential sources of PAHs.
The results show that the highest concentrations of PAHs occurred inwinter, being 143.9 ng/m3 and 182.9 ng/m3 at Tzuo-Yin and Hsiung-Kongsite, respectively; while the lowest concentrations of PAHs occurred insummer, being 81.4 ng/m3 and 95.2 ng/m3. The low-weight PAHs in thetwo sites were abundant in gaseous phase, being 43.8−96.7% and65.2−97.5% at Tzuo-Yin and Hsiung-Kong site, respectively. Meanwhile,the high-weight PAHs were almost present in particulate phase, being40.5−95.2% and 24.8−94.1 % at Tzuo-Yin and Hsiung-Kong site,respectively.
The average PAHs concentrations were 330.04 and 567.81 ng/m3during the rice straw non-burning and burning period in Jhu-Shan site, theaverage PAHs concentrations were 427.16 and 571.80 ng/m3 during therice straw non-burning and burning period in Sin-Gang site, respectively,in the rice straw burning period, which were higher than those on thenon-burning days.
The results of by CMB receptor modeling indicated that the major sources of pollution was exhaust emission (49.5−63.3%) in Tzuo-Yin site,and was burning source (49.1−63.7%) in Hsiung-Kong site in Kaohsiungcity. The results of APCA model analysis indicated that the major sourcesof pollution was mobile source (gasoline and diesel) were 66.5¡Ó8.0%during the rice straw non-burning period, and was mobile (gasoline) andrice straw non-burning source were 57.3¡Ó6.9% during the rice strawburning period in Jhu-Shan site in Central Taiwan. The results of APCAmodel analysis indicated that the major sources of pollution was mobile(gasoline) and plastics incinerator source were 54.3¡Ó6.4% during the ricestraw non-burning period, and was burning incense in temple, rice straw,mobile (gasoline and diesel) source were 50.7¡Ó4.6% during the rice strawburning period in Sin-Gang site in Central Taiwan.
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Polytetrahydrofuran- and dendrimer- based novel sol-gel coatings for capillary microextraction (cme) providing parts per trillion (ppt) and parts per quadrillion (ppq) level detection limits in conjunction with gas chromatography and flame ionization detection (fid)Kabir, Abuzar 01 June 2005 (has links)
Sol-gel capillary microextraction (CME) is a new direction in solvent-free extraction and preconcentration of trace analytes. CME presents significant interest in environmental, pharmaceutical, petrochemical, biomedical, agricultural, food, flavor, and a host of other important areas. Sol-gel CME utilizes advanced material properties of organic-inorganic hybrid sol-gel polymers to perform efficient extraction and enrichment of target analytes from a variety of matrices. In this dissertation, two novel sol-gel coatings were developed for CME: (a) sol-gel benzyl-terminated dendrimer coating, and (b) sol-gel polytetrahydrofuran (poly-THF) coating. A detailed investigation was conducted to evaluate the performance of the newly developed sol-gel coatings in solvent-free extraction of a wide range of polar and nonpolar analytes.
Sol-gel chemistry was used to chemically immobilize dendrimer- and poly-THF-based hybrid organic-inorganic coatings on fused silica capillary inner surface. The sol-gel coatings were created using a coating solution containing a sol-gel active organic component (dendrimer or poly-THF), a sol-gel precursor (methyltrimethoxysilane, MTMOS), a sol-gel catalyst (trifluoroacetic acid, TFA, 5% water) and a deactivating reagent (hexamethyldisilazane, HMDS). Sol-gel reactions were conducted inside a hydrothermally treated fused silica capillary for 60 min. A wall-bonded sol-gel coating was formed via condensation of silanol groups residing on the capillary inner surface with those on the sol-gel network fragments evolving in close vicinity of the capillary walls. Due to the strong chemical bonding with capillary inner walls, these sol-gel coatings showed excellent thermal and solvent stability in CME in hyphenation with gas chromatography (GC).
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Sol-gel immobilized cyano-polydimethylsiloxane and short chain polyethylene glycol coatings for capillary microextraction coupled to gas chromatographyKulkarni, Sameer M 01 June 2007 (has links)
Two highly polar sol-gel coatings were developed for capillary microextraction (CME). One of the coatings contained cyanopropyl-polydimethylsiloxane (CN-PDMS) and the other low molecular weight polyethylene glycol. These highly polar coatings were immobilized via sol-gel chemistry allowing for direct chemical bonding to the inner surface of fused silica capillaries. These sol-gel coated microextraction capillaries were employed in CME for solvent-free microextraction and preconcentration of trace analytes (polar, moderately polar, and nonpolar) from aqueous matrices. CN-PDMS and short chain PEG extraction phases exhibit both polar and polarizable characteristics. Therefore, both sol-gel CN-PDMS and short chain sol-gel PEG coatings were able to extract analytes of different polarity from aqueous media.
Both sol-gel CN-PDMS and sol-gel PEG coatings provided effective extraction of polar analytes such as free fatty acids, alcohols, and phenols without requiring derivatization, pH adjustment or salting out procedures commonly used in SPME experiments with conventional coatings. For each of these coatings, detection limits on the order of nanogram/liter (ng/L) were achieved for both polar and nonpolar analytes extracted simultaneously from aqueous media followed by GC-FID analysis. Both sol-gel CN-PDMS and short chain sol-gel PEG coated microextraction capillaries showed excellent run-to-run and capillary-to-capillary extraction reproducibility (GC peak area RSD < 6% & 5%, respectively) for nonpolar as well as polar analytes. For the sol-gel CN-PDMS coatings, the upper allowable conditioning temperatures were 330 degrees C and 350 degrees C, for the extraction of polar and nonpolar organic analytes, respectively.
Similarly, the sol-gel PEG coatings used for the extraction of polar organic analytes survived a conditioning temperature of 340 degrees C. Both sol-gel CN-PDMS and sol-gel PEG coated microextraction capillaries showed no significant changes in the peak areas of the extracted analytes even after being washed with organic solvents (dichloromethane and methanol (1:1), v/v) for 24 hours. The excellent thermal and solvent stabilities can be attributed to the presence of chemical bonds between the sol-gel coatings and the fused silica surface.
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On the use of hydrophobic biopolymers and hydrophobic biopolymer-coated sands for the removal of naphthalene, phenanthrene, and pyrene from contaminated sedimentsSitzes, Ryan Ziegler 05 August 2011 (has links)
The overall objective of the present study was to evaluate the effectiveness of using a variety of hydrophobic biopolymers and hydrophobic biopolymer-coated sands as technically and economically feasible in-situ sediment amendments or alternative capping materials on a laboratory scale. Cutin from tomato peels, cellulolytic enzyme lignin from sitka spruce chips, and keratin azure from commercially dyed sheeps wool were isolated, prepared, tested, and evaluated as feasible hydrophobic biopolymers for the removal of selected Polycyclic Aromatic Hydrocarbons (PAHs). Testing included chemical and physical characterization, as well as the measurement of kinetics and equilibrium sorption parameters for the sorbates naphthalene, phenanthrene, and pyrene as model hydrophobic organic contaminants. Tomato peel cutin exhibited the largest overall affinity for PAHs, however, keratin azure was selected for further evaluation as the most feasible material due to its low preparation cost.
Amendment of industrial sand with a stable, uniform, cross-linked keratin azure derivative was achieved to produce hydrophobic biopolymer-coated sand products containing zero, moderate, and high mass fractions of sand. Chemical and physical material parameters, as well as kinetics and equilibrium sorption parameters for the sorbates naphthalene, phenanthrene, and pyrene, were then obtained for the coated sand products. This allowed simple finite difference modeling of PAH fate and transport through a thin cap comprised of the same, insight into the specific sorption mechanisms involved, and information which could prove useful in predicting potential of keratin products to provide a suitable capping material. Conclusions and recommendations for future research focus on the technical and economical feasibility of the prepared hydrophobic biopolymers and hydrophobic biopolymer-coated sand products as capping or in-situ sediment amendments. / text
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Μελέτη αποδόμησης των πολυκυκλικών αρωματικών υδρογονανθράκων (PAHs) με χρήση όζοντος / Degradation of polycyclic aromatic hydrocarbons (PAHs) with ozonΚαρκαλέτσης, Θαλάσσης 28 June 2007 (has links)
Ο στόχος την παρούσας εργασίας είναι η αποδόμηση των PAHs με χρήση όζοντος.Για το σκοπό αυτό επιλέξαμε το φαινανθρένιο ως ένωση-μοντέλο σε οργανικό διαλύτη, με απώτερο στόχο την επεξεργασία επικίνδυνων αποβλήτων. / The perpose of this study is the degradation of polycyclic aromatic hydrocarbons with ozon. For this reason we use phenanthrene like model-compound in organic solution.
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1H NMR-based Metabolomics for Elucidating the Mode of Action of Ccontaminants in the Earthworm Eisenia Fetida after Sub-lethal ExposureLankadurai, Brian 08 August 2013 (has links)
There is a growing need to develop rapid and cost-effective ecotoxicological tools for risk assessment because traditional methods examine endpoints such as mortality, which do not provide any insight into the mode of action (MOA) of the chemical. Research presented within this thesis illustrates the potential of 1H NMR-based metabolomics as a rapid and routine ecotoxicological tool that can elucidate a chemical’s MOA and also aid in the identification of metabolites of exposure. Metabolomics involves measuring the fluctuations in the endogenous metabolites of an organism within a cell, tissue, bio-fluid or whole organism in response to an external stressor. We focused on the model polycyclic aromatic hydrocarbon (PAH) phenanthrene, and the perfluoroalkyl acids (PFAAs) perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), due to their recalcitrant nature and widespread prevalence in soil environments. 1H NMR-based metabolomics analysis of the exposure of Eisenia fetida earthworms to sub-lethal phenanthrene exposure via filter paper contact tests revealed a concentration-dependent two-phased MOA: a linear correlation between the metabolic response and exposure concentration at low concentrations followed by a plateau in the responses at high concentrations. Alanine, glutamate, maltose, cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. An increased energy demand and an interruption in the conversion of succinate to fumarate in the Krebs cycle were observed due to phenanthrene exposure. Sub-lethal PFOA and PFOS exposure to E. fetida via contact tests for two days revealed heightened responses with higher PFOA and PFOS concentrations. Leucine, arginine, glutamate, maltose, and ATP were identified as potential indicators of PFOA or PFOS exposure. E. fetida responses were then investigated after exposure for two, seven and fourteen days to an artificial soil that was spiked with sub-lethal PFOS concentrations. An exposure time-dependent operation of two separate MOAs were identified. Both the contact tests and artificial soil exposure studies identified an elevation in fatty acid oxidation, a disruption in energy metabolism and biological membrane structure, and also an interruption of ATP synthesis following PFOA and PFOS exposure. This thesis illustrates the promise of NMR-based metabolomics as a routine tool for ecotoxicological assessment of contaminated sites.
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