The effect of copper speciation on the formation of chlorinated aromatics on real municipal solid waste incinerator fly ash

A limited amount of information exists regarding the relationship between the chemical form of copper and the formation of chlorinated aromatics in fly ash. To understand the effects of the various forms of copper on the formation of chlorinated aromatics in real fly ash, we determined the chemical forms of copper present in various types of real fly ash using X-ray absorption near edge structure (XANES) and evaluated the relationship between the chemical forms of copper and the formation of chlorinated aromatics. Copper chloride hydroxide (CuCl2 x 3Cu(OH)2) and cuprous chloride (CuCl) were the predominant copper species found in real fly ash. Although pure cupric chloride (CuCl2) is known to be the most active catalyst for the formation of chlorinated aromatics under experimental conditions with synthetic fly ash, CuCl2 was not found in every real fly ash sample. The amount of copper chloride hydroxide was positively correlated with the formation of chlorinated aromatics in real fly ash and is, consequently, considered to be one of the key species involved in the formation of chlorinated aromatics.     

Study on the pyrolysis of polyethylene in the presence of iron and copper chlorides

Pyrolysis experiments were conducted to elucidate the effects of metal chlorides on the thermal degradation of low-density polyethylene on a continuous pyrolysis temperature range of 600 degrees C to 1100 degrees C. The present work focusses on the ratio of aromatics generated on increasing the pyrolysis temperature in the presence of metal salts, iron(II), iron(III) and copper(II) chlorides. It was observed that beside alpha,omega-dienes, alpha-olefins and n-alkanes which are usually observed during the thermal decomposition of polyethylene, the level of aromatics noticeably increases with the addition of metal salts. At high temperatures, the formation of these aromatics took place in such a way that they become the major products when polyethylene is pyrolyzed in presence of FeCl(3) and CuCl(2). Quantification of the effect of metal salts has been tempted comparing the variation of the ratio of aromatics with pyrolysis temperatures. Mechanisms responsible for the formation of these aromatics in presence of metal salts have been tentatively investigated. They are proposed to result from cyclization/dehydrogenation reactions similar to those observed during the thermal decomposition of polyethylene, but with an increased efficiency due to the metal salts.     

Metal catalyzed formation of chlorinated aromatic compounds: a study of the correlation pattern in incinerator fly ash

Chlorinated aromatics are unintentionally formed and released from combustion and other thermal processes involving organic matter and chlorine. The catalytic activity of incinerator fly ash in the low-temperature formation of chlorinated aromatics has been demonstrated in both laboratory experiments and full-scale trials. Copper has been shown to be an effective catalyst, but several other transition metals possess a similar activity. Here results are reported from a series of full-scale combustion trials with different fractions of household and industrial wastes, with waste from forestry as a reference fuel. The composition of elements and chlorinated aromatics in the fly ash was evaluated with principal component analysis and partial least squares regression. The observed correlation pattern indicates that metals other than copper are of equal importance for the catalytic activity. Chromium and nickel are two of these metals, which may contribute to the de novo formation of chlorinated benzenes, phenols, PCDD and PCDF.     

Halogenated aromatics from steel production: results of a pilot-scale investigation

The potential environmental impact of emissions of halogenated aromatics from the steel industry is of growing concern. It has been suggested that electric arc furnaces are the only industrial source with constant or increasing emissions of dioxins to air. Here the results are reported from a pilot plant study on how scrap composition and various treatment alternatives affect the formation and release of chlorinated and brominated aromatics. The experiments were conducted with a statistical mixture design, and it is shown that scrap composition has a significant impact on the outcome. In contrast, the various treatment schemes examined--shredding, disassembly, and briquetting--did not affect the formation and release of halogenated aromatics. Parallel experiments with injection of adsorbents showed that it is possible to reduce emissions without substantial investments, and this option is recommended as a low-cost solution.     

A modeling evaluation of the effect of chlorine on the formation of particulate matter in combustion

The effect of chlorine on the fuel-rich oxidation of hydrocarbons and on the molecular weight growth of aromatics is analyzed by simulating experiments featuring a model chlorinated additive CH3Cl in a jet-stirred/plug-flow reactor and premixed flames. The kinetic model used in this work emphasizes the role of resonantly stabilized radicals in the formation and growth of aromatics, and considers soot inception as the net effect of molecular weight growth and graphitization of aromatic structures. Chlorinated hydrocarbons decompose at temperatures significantly lower than hydrocarbons, producing reactive Cl-atoms, which have a strong tendency to go to HCl. The HCI, tying up the H-atoms, inhibits hydrocarbon oxidation. The model is able to predict not only the levels but the shape of the experiments quite well and also the surprising finding of an increased soot formation associated with lower PAH levels found in rich flames with significant levels of chlorine. Based on reaction kinetic analysis, chlorine addition to the fuel enhances soot formation by promoting the formation of aromatic-ring compounds and accelerating the abstraction of aromatic H-atoms from stable PAH molecules. This process activates the transformation of aromatics to soot.     

Chlorinated aromatics from the combustion of hazardous waste

The production and emission of chlorinated aromatics from a hazardous waste incinerator were shown to be influenced by the operating conditions.     

Effect of Fuel Properties on Mutagenic Activity in Extracts of Heavy-duty Diesel Exhaust Particulate

The effect of varying fuel properties on the emission of mutagenic materials was studied in diesel exhaust particles from a heavy duty engine run under transient speed and load conditions while using nine fuels varying in aromatics, sulfur and boiling point. Mutagenic activity of the soluble organic fraction (SOF) of the particulate was determined using the Ames Salmonella test system with strain TA98 with and without S9 activation. Increasing mutagenic activity relative to fuel consumed (mutants/lb fuel) or to engine work output (mutants/hp-h) was correlated with increasing fuel aromatics (p < 0.05), but not with fuel sulfur. Increased fuel sulfur levels were correlated with increased amounts of SOF but with decreasing mutagenic activity of the SOF (mutants/microgram SOF) (p < 0.05). As a result, mutants/hp-h were essentially the same for high- and low-sulfur fuels with high aromatics. No association was found between the fuels’ boiling points and the mutagenic activity of the SOF. Mutagenic activity with S9 was generally lower than without, but the correlations were not changed.     

Effect of fuel properties on mutagenic activity in extracts of heavy-duty diesel exhaust particulate.

The effect of varying fuel properties on the emission of mutagenic materials was studied in diesel exhaust particles from a heavy duty engine run under transient speed and load conditions while using nine fuels varying in aromatics, sulfur and boiling point. Mutagenic activity of the soluble organic fraction (SOF) of the particulate was determined using the Ames Salmonella test system with strain TA98 with and without S9 activation. Increasing mutagenic activity relative to fuel consumed (mutants/lb fuel) or to engine work output (mutants/hp-h) was correlated with increasing fuel aromatics (p less than 0.05), but not with fuel sulfur. Increased fuel sulfur levels were correlated with increased amounts of SOF but with decreasing mutagenic activity of the SOF (mutants/microgram SOF) (p less than 0.05). As a result, mutants/hp-h were essentially the same for high- and low-sulfur fuels with high aromatics. No association was found between the fuels' boiling points and the mutagenic activity of the SOF. Mutagenic activity with S9 was generally lower than without, but the correlations were not changed.     

Wind Dispersion: A Program for the Texas Instruments 59 Calculator

Simultaneous measurements of individual hydrocarbons and individual carbonyls were carried out at a downtown Los Angeles location. Concentrations are presented for 50 compounds in morning air samples. While paraffins (C ≥ 4) were a major hydrocarbon subclass on a ppmC basis, higher aromatics (C ≥ 8) were the major component when taking reactivity considerations into account. Comparison of the results with emission inventory data showed good agreement for many hydrocarbons and for paraffins as a subclass. Measured olefins and aromatics concentrations were substantially lower and higher, respectively, than those expected from inventory data.     

Base-neutral extractable organic pollutants in biota and sediments from Lake Pontchartrain

A study was conducted to screen the three passes that link Lake Pontchartrain to the Gulf of Mexico via Lake Borne for the presence of EPA base-neutral (BN) priority pollutants and any other pollutants detected in significant concentration. Biota and sediment samples were collected and analytical procedures were developed for the trace analysis of BN organics in these matrices. Compounds identified include alkanes (normal, branched, cyclic), alkenes, aromatics, alkylated aromatics, polynuclear aromatic hydrocarbons and their alkylated derivatives, phthalates, ketones, furans, thiophenes, phenols, amines, nitriles, thiazoles, amides, aldehydes, alcohols, free fatty acids, fatty acid methyl and ethyl esters, phosphates, sterols. Concentrations were in the parts-per-billion range.     

Source location and characterization of volatile organic compound emissions at a petrochemical plant in Kaohsiung, Taiwan

This paper elucidated a novel approach to locating volatile organic compound (VOC) emission sources and characterizing their VOCs by database and contour plotting. The target of this survey was a petrochemical plant in Linyan, Kaohsiung County, Taiwan. Samples were taken with canisters from 25 sites inside this plant, twice per season, and analyzed by gas chromatography-mass spectrometry. The survey covered 1 whole year. By consolidated into a database, the data could be readily retrieved, statistically analyzed, and clearly presented in both table and graph forms. It followed from the cross-analysis of the database that the abundant types of VOCs were alkanes, alkenes/dienes, and aromatics, all of which accounted for 99% of total VOCs. By contour plotting, the emission sources for alkanes, aromatics, and alkenes/ dienes were successfully located. Through statistical analysis, the database could provide the range and 90% confidence interval of each species from each emission source. Both alkanes and alkene/dienes came from tank farm and naphtha cracking units and were mainly composed of C3-C5 members. Regarding aromatics, benzene, toluene, and xylenes were the primary species; they were emitted from tank farm, aromatic units, and xylene units.     

An evaluation of two fluorescence screening methods for the determination of chrysene metabolites in fish bile

Two screening methods, synchronous fluorescence spectrometry (SFS) and high performance liquid chromatography with fluorescence detection (HPLC-F), have been evaluated for their suitability in determining chrysene metabolites in fish bile. The optimal wavelength pair, excitation/emission 272/374 nm, for SFS measurements of chrysene metabolites was identified by analysis of bile taken from fish exposed to the pure compound. This analysis revealed in addition some information about the metabolite pattern. However, when bile from fish exposed to complex and environmentally relevant mixtures of polycyclic aromatic hydrocarbons (PAHs) was analysed using these methods, identification of the chrysene metabolites was poor. Analysis of bile taken from fish exposed to single PAHs identified other three- and four-ring aromatics as the main interfering compounds. Both methods were equally able to discriminate between impacted and reference sites by determination of relative concentrations of fluorescent three- and four-ring aromatics.     

Source Location and Characterization of Volatile Organic Compound Emissions at a Petrochemical Plant in Kaohsiung,Taiwan

Abstract

This paper elucidated a novel approach to locating volatile organic compound (VOC) emission sources and characterizing their VOCs by database and contour plotting. The target of this survey was a petrochemical plant in Linyan, Kaohsiung County, Taiwan. Samples were taken with canisters from 25 sites inside this plant, twice per season, and analyzed by gas chromatography–mass spectrometry. The survey covered 1 whole year. By consolidated into a database, the data could be readily retrieved, statistically analyzed, and clearly presented in both table and graph forms. It followed from the cross‐analysis of the database that the abundant types of VOCs were alkanes, alkenes/dienes, and aromatics, all of which accounted for 99% of total VOCs. By contour plotting, the emission sources for alkanes, aromatics, and alkenes/dienes were successfully located. Through statistical analysis, the database could provide the range and 90% confidence interval of each species from each emission source. Both alkanes and alkene/dienes came from tank farm and naphtha cracking units and were mainly composed of C₃–C₅ members. Regarding aromatics, benzene, toluene, and xylenes were the primary species; they were emitted from tank farm, aromatic units, and xylene units.     

Anaerobic formation and degradation of toxic aromatic compounds in agricultural and communal sewage deposits

Relatively high concentrations of phenol, p-cresol, phenylacetic acid and other aromatic compounds were found in agricultural and communal sewage deposits. These toxic aromatic compounds are products of the bacterial degradation of aromatic amino acids under anaerobic conditions. In laboratory experiments at 26 degrees C and under N2-atmosphere, the same aromatics were formed from the amino acid tyrosine and from gelatine in assays inoculated with sewage sludge. After exhaustion of tyrosine and gelatine, respectively, concentrations of the accumulated phenol and other aromatics remained stable for months, i.e., phenol, p-cresol, phenylacetic acid etc. are dead-end products of the bacterial metabolism under these conditions. After addition of sodium nitrate the aromatic compounds are metabolically decomposed by denitrification within weeks.     

Hexachlorobenzene as an indicator of dioxin production from combustion

The production of polychlorinated dioxins and dibenzofurans shows a strong correlation with the production of hexachlorobenzene. Hexachlorobenzene can be used as an indicator for the production of chlorinated aromatics.     

Aromatic photonitration in homogeneous and heterogeneous aqueous systems

This work describes the nitration of aromatics upon near-UV photolysis of nitrate and nitrite in aqueous solution and upon photocatalytic oxidation of nitrite in TiO2 suspensions. Phenol is used in this work as a model aromatic molecule and as a probe for *NO2/N2O4. The photoinduced nitration of phenol in aqueous systems occurs upon the reaction between phenol and *NO2 or N2O4, and is enhanced by the photocatalytic oxidation of nitrite to *NO2 by TiO2. Aromatic photonitration in the liquid phase can play a relevant role in the formation of nitroaromatics in natural waters and atmospheric hydrometeors, thus being a potential pathway for the condensed-phase nitration of aromatics. Furthermore, the photoinduced oxidation of nitrite to nitrogen dioxide suggests a completely new role for nitrite in natural waters and atmospheric aerosols.     

Ecological assessment of the environmental impacts of the kerosene burning in jet turbines and its improvement assessment

The burning of kerosene in jet turbines is investigated for two reference flights with a Boeing 747-400 and an Airbus A320-200, representing the typical Lufthansa planes for long and middle distance. The ecological evaluation is performed by Life Cycle Assessment (LCA). Formation of condensation trails, which is a specific environmental impact caused by air traffic, has to be considered in addition to established LCA impact categories. Based on the ecological assessment, an improvement assessment is performed. Environmental performance of diesel fuel during the combustion in car engines is analysed based on available publications. The relevant parameters for the environmental impact of the combustion of diesel (aromatics content, reduction of sulphur content, the reduction of the density and raising of the cetane number) are discussed with regard to improvements of the exhaust qualities of kerosene. A reduction of the aromatics content promises to improve the emission of soot which should be further investigated.     

Speciation and quantification of vapor phases in soy biodiesel and waste cooking oil biodiesel

This study characterizes the compositions of two biodiesel vapors, soy biodiesel and waste cooking oil biodiesel, to provide a comprehensive understanding of biodiesels. Vapor phases were sampled by purging oil vapors through thermal desorption tubes which were then analyzed by the thermal desorption/GC/MS system. The results show that the compounds of biodiesel vapors can be divided into four groups. They include methyl esters (the main biodiesel components), oxygenated chemicals, alkanes and alkenes, and aromatics. The first two chemical groups are only found in biodiesel vapors, not in the diesel vapor emissions. The percentages of mean concentrations for methyl esters, oxygenated chemicals, alkanes and alkenes, and aromatics are 66.1%, 22.8%, 4.8% and 6.4%, respectively for soy biodiesel, and 35.8%, 35.9%, 27.9% and 0.3%, respectively for waste cooking oil biodiesel at a temperature of 25 ± 2 °C. These results show that biodiesels have fewer chemicals and lower concentrations in vapor phase than petroleum diesel, and the total emission rates are between one-sixteenth and one-sixth of that of diesel emission, corresponding to fuel evaporative emissions of loading losses of between 106 μg l⁻¹ and 283 μg l⁻¹. Although diesels generate more vapor phase emissions, biodiesels still generate considerable amount of vapor emissions, particularly the emissions from methyl esters and oxygenated chemicals. These two chemical groups are more reactive than alkanes and aromatics. Therefore, speciation and quantification of biodiesel vapor phases are important.     

Evaluation of non-enteric sources of non-methane volatile organic compound (NMVOC) emissions from dairies

Dairies are believed to be a major source of volatile organic compounds (VOC) in Central California, but few studies have characterized VOC emissions from these facilities. In this work, samples were collected from six sources of VOCs (Silage, Total Mixed Rations, Lagoons, Flushing Lanes, Open Lots and Bedding) at six dairies in Central California during 2006–2007 using emission isolation flux chambers and polished stainless steel canisters. Samples were analyzed by gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. Forty-eight VOCs were identified and quantified in the samples, including alcohols, carbonyls, alkanes and aromatics. Silage and Total Mixed Rations are the dominant sources of VOCs tested, with ethanol as the major VOC present. Emissions from the remaining sources are two to three orders of magnitude smaller, with carbonyls and aromatics as the main components. The data suggest that animal feed rather than animal waste are the main source of non-enteric VOC emissions from dairies.     

Sampling of polychlorinated aromatics in workroom air using Amberlite XAD-2 resin

Amberlite XAD-2 porous polymer was evaluated for the solid sampling of PCBs, PCNs, tri-, tetra-and pentachlorophenol in workroom air. Using solvent desorption, the recoveries of these compounds from XAD-2 was mostly about 80%, showing this adsorbent to be an excellent medium for the sampling of polychlorinated aromatics in air.