Fly Ash Extract Research Articles

Effect of oxydesulphurization on the combustion characteristics of coal

Abstract Desulphurization of a Turkish lignite by oxydesulphurization using dilute alkaline solutions, obtained by the extraction of fly ash with water, was carried out under 0–1.5 MPa partial pressure of oxygen at temperatures between 403 and 498 K for 30–90 min time intervals. TGA was performed to compare the combustion characteristics of original and desulphurized lignite samples. DTG curves were derived and the effects of desulphurization conditions such as temperature, partial pressure of oxygen and time on coal reactivity were studied considering ignition temperature, maximum combustion rate, combustion period, and the end temperature of combustion. Relations between coal reactivity and removals of sulphur and ash contents were also studied.

Observations on the effect of process parameters on dioxin/furan yield in municipal waste and coal systems

Effects of fly ash loading; ash-borne, extractable organics; sulfur dioxide (SO 2) and hydrogen chloride (HCl) concentration; and combustion quality on the formation of polychlorinated dibenzo- p-dioxin and polychlorinated dibenzofuran (PCDD/F) were evaluated in pilot scale tests simulating municipal waste combustion and coal/waste co-combustion testing. Similar PCDD/F yields from reinjection of as-received and extracted fly ash injection along with testing under “poor combustion” conditions show the importance of combustion quality on minimizing precursors. Co-firing coal and municipal solid waste ash leads to increased formation from that of firing coal alone, indicating that the municipal solid waste ash provides additional reactants and/or catalytic sites for formation. Finally, tests with elevated SO 2 levels found that, at sufficiently high sulfur/chlorine levels, formation of PCDD/F is prevented in both simulated municipal waste combustion and coal/waste co-firing.

96/05601 Results from an international intercalibration study on PCDDs and PCDFs in a fly ash extract

96/05601 Results from an international intercalibration study on PCDDs and PCDFs in a fly ash extract

Results from an international intercalibration study on PCDDs and PCDFs in a fly ash extract

Three fly ash extracts, of which two fortified with different PCDFs and PCDFs congeners, were analysed by eight different laboratories. The results show relatively good precision, RSD for levels reported as TEQs are below 25%. Problems with the analysis of 1,2,3,7,8,9-HxCDF was observed. Multivariate data analysis was performed to explore the data and principal component analyses of the data set revealed clustering of different laboratories.

Simultaneous determination of chromium (III) and chromium (VI) by reversed-phase ion-pair HPLC with chromium-specific detection

A method for the simultaneous determination of Cr(III) and Cr(VI) with reversed-phase ion-pair HPLC employing chromium-specific detection by flame atomic absorption spectrometry (FAAS) and inductively-coupled plasma mass spectrometry (ICP-MS) is presented. Experimental parameters of the chromatographic separation, such as concentration of the ion-pairing reagent, pH and polarity of the mobile phase have been optimized for two different ion-pairing reagents, tetrabutylammonium phosphate (TBA) and tetraethylammonium nitrate (TEA). Best chromatographic conditions have been obtained with a polymer-based reversed-phase column (Hamilton PRP1) and mobile phases containing either TBA (1 mmol/l) in methanol-water (60:40, v/v) or TEA (2 mmol/l) in water at a pH between 3 and 4. With FAAS the detection limits (3σ) have been found to be 24 μg/l for Cr(III) and 40 μg/l for Cr(VI). A detection limit of 0.3 μg/l Cr(3σ) for both chromium species has been obtained when ICP-MS has been used for detection. The method has been applied to analyze tap- and groundwater and to investigate the behaviour of Cr(III) and Cr(VI) in spiked tap-water, as well as to analyze aqueous extracts of coal fly ash (NIST SRM 1633a) and of an ash from a wood treatment company.

PARC an automated apparatus for clean-up procedures used in routine-analysis for PCDD/PCDF and related compounds

PARC (Processor for Automatic Routine Clean-up) is a concept to automate and control complex liquid chromatographic assemblies. Pivotal is a control software, which assists a particular control programming language, an user definable screen and a programmable dialogue with the operator of an application. The language has been constructed to obtain an easy programmable time controller and to create applications in routine analysis, which can be handled easily. The software allows a process visualisation and can be utilized in all sections of liquid chromatography (HPLC, MPLC and preparative LC) and is a tool for development of chromatographic methods, further for teaching and for demonstration purposes. The controller is utilized for clean-up procedures of polychlorinated dioxins and furans (PCDD/PCDFs) and chlorobenzenes from extracts of waste incinerator fly ash and other matrices. Clean-up procedures according to VDI-guidelines were chosen. The automated alumina column clean-up and the modular combination of H 2SO 4-silica and alumina column clean-up proved to be highly reproducible with recoveries mainly higher than 90%.

Carbon dioxide supercritical fluid extraction of incinerator fly ash with a reactive solvent modifier

Carbon dioxide supercritical fluid extraction was used to extract polycyclic aromatics, halogenated phenols, halogenated aromatics and dioxins from a municipal incinerator fly ash matrix. The extraction solvent was modified with methanol or a reactive solvent modifier, N,O-bis-trimethylsilyl-trifluoroacetamide (BSTFA), which was added to the sample before extraction. Extracts, obtained at two temperatures and with three supercritical fluid formulations, were analyzed by the US Environmental Protection Agency contract laboratory program GC-MS procedure for semi-volatile organic compounds. Average recoveries of surrogate analytes with pure carbon dioxide and carbon dioxide modified with methanol were 50% (500 atm and 100°C). Average recoveries were 82% at 100°C and 54% at 30°C with BSTFA present. Carbon dioxide modified with methanol was found to be less efficient than carbon dioxide modified with BSTFA. Unlike earlier uses of reactive modifiers, the acidic and phenolic components were determined as the free acids and phenols. Hydrolysis of trimethylsilyl derivatives of phenols, produced by the modifier during the extraction, with methanol reproduced the free phenols. At 60°C the average hydrolysis yield of the four phenols was 96.7%. This hydrolysis step also allowed analysis of free acids by standard methods.

Supercritical fluid extraction and clean‐up with temperature fractionation: Application to determination of polychlorinated dibenzo‐ρ‐dioxins

AbstractSupercritical fluid extraction (SFE) and clean‐up with neat carbon dioxide (CO2), selective sorbents and high extraction temperature was developed as a sample preparation method. The effects of temperature and pressure on SFE efficiencies were investigated by spiking a polychlorinated dibenzo‐ρ‐dioxin (PCDD)/polychlorinated biphenyl (PCB) standard mixture onto a Florisil™ adsorbent and extracting these compounds at different temperatures and pressures with neat CO2. High extraction temperatures and pressures were found to increase the extraction rate and efficiency. PCDDs were quantitatively extracted from Florisil™ only when the temperature was raised to 200°C and the pressure was 9000 psi. PCBs were efficiently extracted at low temperature and pressure, such as 50°C and 2000 psi. Fractionation of PCBs from PCDDs with Florisil™ using CO2 was accomplished by first quantitatively recovering all of the PCBs at 3500 psi and 80°C and then the dioxins at 9000 psi and 250°C.The determination of PCDDs in fly ash was carried out by spiking the fly ash extract (obtained after 80 min extraction at 250°C and 9400 psi using neat CO2) onto FlorislTM, followed by the clean‐up step outlined above. This step produced much cleaner chromatograms compared to direct extraction. The modifier‐free high temperature SFE method produced comparable results to 20 h Soxhlet extraction of fly ash, but it was shorter by an order of magnitude.

Certification of the contents of five polychlorodibenzo-p-dioxins (D48, D54, D66, D67, D70), and six polychlorodibenzo-furans (F83, F94, F114, F121, F124, F130) in a fly ash extract (CRM 429)

A fly ash extract was prepared and studied for the homogeneity and the stability (CRM 429) with respect to five polychlorodibenzo-p-dioxins (D48, D54, D66, D67 and D70) and six polychlorodibenzofurans (F83, F94, F114, F121, F124 and F130). The certification exercise is described; the analytical techniques used for the certification and the quality control guidelines that were followed are also given. The difficulties encountered in the determination of F118 are discussed.

Chemical and biological 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin equivalents in fly ash from combustion of bleached kraft pulp mill sludge

AbstractFly ash was collected from five large‐scale or pilot tests in which burning of bleached kraft pulp mill sludge was studied. The content of dioxin‐like compounds in this fly ash was estimated both chemically and biologically. Fly ash was analyzed chemically for 17 PCDD and PCDF congeners by high‐resolution GC‐MS, and the data were transformed to Nordic TCDD equivalents. The biological analyses were based on the induction of several enzymes (aryl hydrocarbon hydroxylase [AHH], 7‐ethoxyresorufin O‐deethylase [EROD], aldehyde dehydrogenase‐3 [ALDG3]) by the fly ash extracts in a mouse hepatoma cell line, Hepa‐1. The inducing potencies were expressed as biological TCDD equivalents. There was a good correlation between the Nordic and the biological TCDD equivalents. Differences in the amounts of dioxin‐like compounds among the combustions were attributed mainly to the boiler types and not to fuel characteristics or combustion parameters.

Determination of selenium species in coal fly ash extracts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of selenium species in coal fly ash extractsNancy D. Niss, John F. Schabron, and Terry H. BrownCite this: Environ. Sci. Technol. 1993, 27, 5, 827–829Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1 May 1993https://doi.org/10.1021/es00042a003RIGHTS & PERMISSIONSArticle Views186Altmetric-Citations20LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (365 KB) Get e-Alerts Get e-Alerts

Cytochrome P450IA1 induction in mouse hepatoma cell culture as an indicator of polycyclic organic compounds in fly ash

The inducibility of cytochrome P450IA1 (detected as aryl hydrocarbon hydroxylase AHH and 7-ethoxyresorufin O-deethylase EROD) in the mouse hepatoma cell line Hepa-1 has been used as a bioassay for polycyclic organic compounds in fly ash samples collected from combustion of barking material, biosludge and natural gas in a fluidized bed combustor. An amount corresponding to 25 mg fly ash resulted in half of the maximal induction (ED50) of both AHH and EROD. The induction was only observed using the fly ash fraction, which contained planar aromatic compounds (PAHs, PCDDs and PCDFs, the so-called “TCDD-equivalents”). The fly ash extracts were not cytotoxic in the concentrations studied, as judged by counting viable cells or by determination of total protein content in the cultures. The Hepa-1 test, which measures induction of the cytochrome P450IA1 enzyme, seems to be a useful short-term bioassay when information about the biological response of complex environmental samples is needed.

Use of Carbon-13 Labelled Dioxins Mixture for Analysis of Polychlorinated Dibenzo-p-Dioxins in Environmental Samples by GC-MS

Abstract Positive identification and quantitation of polychlorinated dibenzo-p-dioxins (PCDD) in complicated environmental samples is described using a C-13 labelled dioxin mixture as an internal reference standard. Environmental samples are spiked with the C-13 labelled dioxin mixture and monitored for labelled and unlabelled dioxins using GC-MS in the electron impact selected ion monitoring (EISIM) mode. The C-13 labelled dioxin mixture and a municipal solid waste (MSW) incinerator fly ash extract show the same number of isomers in each tetra to octa-chlorodioxin congener groups. Quantitation of the C-13 labelled dioxin mixture was carried out using a reference standard mixture of unlabelled dioxins consisting of at least one isomer for each congener group. The C-13 labelled dioxin standard is highly useful for the determination of retention windows for tetra- to octa-chlorodioxins, identification of dioxins in each congener group, and calculation of the recovery of dioxins in samples that require exten...

Genotoxicity of coal fly ash, assessed in vitro in Salmonella typhimurium and human lymphocytes, and in vivo in an occupationally exposed population

Fly ash as a product of coal combustion is known to contain various mutagenic substances, but genotoxic properties, especially of the particular (larger-size) fly ash fraction which is electrostatically precipitated (ESP) in the energy plant, have hardly been investigated. While smaller-size fly ash particles escape through the stack during powder coal combustion, the ESP fraction is collected and used for the manufacturing, for instance according to the Lytag process, of secondary products which can serve several construction purposes. Since fly ash as well as fly ash products are generally introduced into the human environment, a study of possible genotoxic effects to human DNA is indicated. Mutagenic properties of ESP fly ash, as well as of the Lytag product, were investigated by means of the Salmonella microsome assay. The capacity to cause human chromosome damage of both ESP fly ash and Lytag dust was studied in vitro by application of the sister-chromatid exchange (SCE) test using human lymphocytes. Furthermore, effects of ESP fly ash/Lytag dust on the incidence of SCE in peripheral lymphocytes in vivo were measured in an occupationally exposed, male population, using individually matched employees from a flour-processing industry as the control population. It is demonstrated that ultrasonically treated DMSO extracts of ESP fly ash are slightly mutagenic to Salmonella tester strains TA97 and TA102. Lytag dust is effective in inducing reversions in all tester strains. Furthermore, it appeared that both compounds significantly increase the SCE frequency of human lymphocytes after incubation in vitro in comparison to non-exposed cells. Also, peripheral lymphocytes of the occupationally exposed population show a considerably higher incidence of SCE than the control population. Major disturbing factors in assessing the effects of occupational exposure to fly ash/Lytag dust on lymphocyte SCE frequency appeared to be smoking behavior and alcohol consumption. It is concluded that exposure to fly ash from powder coal combustion implies a moderate genotoxic risk to man.

Evaluation of clean-up methods for the determination of chlorinated aromatic hydrocarbons in fly-ash by capillary gas chromatography and mass selective detection

This study describes an evaluation of different clean-up methods for the determination of polychlorinated dibenzo-p-dioxins and-dibenzofurans (PCDD/F extracts of fly-ash. The PCDD/F fractions obtained were additionally investigated for the presence or absence of polychlorinated benzenes (PCBz), polychlorinated biphenyls (PCB) and polychlorinated phenols (PCP) to detect any interference, and to test for determinability in the same fractions. Three different methods were compared, viz. solid phase extraction (SPE) using disposable benzenesulphonic acid and silicagel cartridges, multilayer silicagel plus alumina column chromatography (MLA); and an active carbon method plus multilayer silicagel plus alumina column chromatographic (ACM) method. The fractions obtained were analyzed by capillary gas chromatography and mass selective detection using the isotope dilution method. Both the variances and the levels of PCDD/F showed good agreement between the different clean-up methods investigated. The SPE-method, being fast and simple, should be preferred for the determination of PCDD/F in fly-ash; it also allows the determination of PCBz and PCB in the fractions. The presence of PCBz and PCB in the clean-up fractions does not interfere with the determination of PCDD/F provided that the mass spectra of PCDD/F are checked for [M-COCI] fragments.

Hepatic retention of PCDDs and PCDFs in C57BI/6 and DBA/2 Mice

The hepatic retention of PCDDs and PCDFs was studied in C57BI/6 and DBA/2 mice. Mice received a single oral dose of an artificial mixture of 2,3,7,8-substituted PCDDs and PCDFs, a fly ash extract from a municipal incinerator and an Aroclor 1254 mixture. In all experiments 2,3,7,8-PCDDs and PCDFs were the major congeners retained in the liver. The only otherwise substituted congeners retained to some measurable extent were 2,3,6,7-TCDF and 2,3,4,6,7-PnCDF. Quantitatively, no significant differences were found between both strains for most of the retained congeners. It is concluded that the genetic differences at the Ah-locus between both mice strains do not influence the hepatic retention of PCDDs and PCDFs.

Pyrolysis of dibenzodioxin, dibenzofuran and 1,2,3,4-tetrabromodibenzodioxin with different chlorine donors and catalysts

Dibenzodioxin, dibenzofuran and 1,2,3,4-T 4BrDD were pyrolysed with conc. HCl, NaCl or PVC at 800°C and 900°C for 10 min in an open quartz tube. Dibenzodioxin and dibenzofuran were also pyrolysed with conc. HCl and catalysts such as AlCl 3, CuCl 2 and extracted fly ash. The residues were dissolved in toluene and analysed by HRGC/MS. Only MCDD was detected when dibenzodioxin was pyrolysed using conc. HCl, conc. HCl AlCl 3 or conc. HCl/fly ash. MCDD, DCDD, T 3CDD and T 4CDD were detected in the pyrolysate of dibenzodioxin with conc. HCl CuCl 2 . Only MCDF was found in the pyrolysate of dibenzofuran with conc. HCl AlCl 3 and conc. HCl CuCl 2 . Low chlorinated dioxins were formed in the pyrolysis of dibenzofuran with conc. HCl, conc. HCl AlCl 3 and conc. HCl CuCl 2 . In all reactions of 1,2,3,4-T 4BrDD, an exchange of bromine for chlorine was observed. Pyrolysis of 1,2,3,4-T 4BrDD at 800°C with PVC, resulted in 46% of the starting material being transformed to brominated/chlorinated dioxins (Br/Cl-DD) (39.7%) and 1,2,3,4-T 4CDD (6.3%). The yield of Br/Cl-DD and 1,2,3,4-T 4CDD at 900°C was 69%, and 34.7% conversion to 1,2,3,4-T 4CDD was observed. In the reaction with HCl (T=900°C), 49.2% Br/Cl-DD and 1,2,3,4-T 4CDD were formed. Pyrolysis with NaCl at 900°C yielded 10.5% conversion to Br/Cl-DD or 1,2,3,4-T 4CDD.

Octan-1-ol / water partition coefficients of polychlorinated dibenzo-p-dioxins and dibenzofurans : Experimental values determined with a stirring method

Octan-1-ol/water partition coefficients of a mixture of polychlorinated dibenzo-p-dioxins and dibenzofurans, originating from a fly-ash extract, were experimentally determined. A “(slow) stirring method” was used and values thus obtained were as high as 10 8.

Application of carbon-13 labelled dioxins mixture for analysis of polychlorinated dibenzo-p-dioxins in environmental samples by GC-MS

Positive identification and quantitation of polychlorinated dibenzo-p-dioxins (PCDD) in complicated environmental samples is described using C-13 labelled dioxin mixture as an internal reference standard. The C-13 labelled dioxin mixture as an internal reference standard. The C-13 labelled dioxin mixture and a municipal incinerator (MSW) flyash extract shows the same number of isomers in each tetra to octa-chloro dioxin congener groups. The C-13 labelled dioxin standard is highly useful for determination of retention windows for tetra- to octa-chlorodioxins, identification of dioxins in each congener group, and calculation of recovery of dioxins in samples that require extensive sample clean up prior to GC-MS analysis. Its application for retention time window determination and as an internal reference standard for quantitation of dioxins in MSW flyash extract and identification of dioxins in a complex sample from a PCB fire and a fish tissue is demonstrated.

Determination of tetrachlorobiphenylenes (TeCBPs) in flyash extracts containing planar aromatic compounds

A method has been developed for the separation of TeCBPs in extracts containing planar aromatic compounds. Our results indicate that extreme care should be taken in their separation and determination, since interfering compounds are likely to give overestimations regarding their levels. This method has been used successfully in analysing TeCBPs, TeCANs, TeCDDs and TeCDFs in flyash from municipal incinerators in Japan. The major planar aromatic compounds in flyash seem to be TeCDDs followed by TeCDFs > TeCANs > TeCBPs. We did not find 2367-TCBP in flyash from municipal incinerators.