Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry

1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed in order to assess the behaviour of the mineral matter contained within the wood and coal samples. 32% of the biomass was extracted at the higher temperature and 12% at room temperature while only 12% of the coal was extracted at the higher temperature and 3% at room temperature. Less than 2% of the ash dissolved at the higher temperature. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials (>1000 mu) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass sample were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash. Be and Sb were not quantified in the extracts because they were present at too low concentrations; up to 40% of Mn was extracted from the biomass sample at 202 degrees C, while Se was totally extracted from the ash sample. For the forest residue, approximately 7% (at room temperature) and 45% (at 202 degrees C) of the total trace elements studied were in the extract; for the coal, approximately 8% (at room temperature) and 23% (at 202 degrees C) were in the extract. For the ash, only 1.4% of the trace elements were extracted at 202 degrees C, comprising 25% of Cd but less than 1% of Pb.     

Partitionings and kinetic behaviors of major-to-ultratrace elements between industrial waste incineration fly and bottom ashes as studied by ICP-AES and ICP-MS.

The partitionings of major-to-ultratrace elements between industrial waste incineration fly ash (IWIFA) and industrial waste incineration bottom ash (IWIBA) in industrial waste incinerators were investigated by measuring their concentration distributions, where the incineration ash samples were collected from three different types of industrial waste incinerators. The concentrations of the elements in the incineration ash samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). As a result, ca. 40 elements in the concentration range from mg g(-1) to sub-microg g(-1) could be determined in both IWIFA and IWIBA samples. The concentration ratios of CF/CB (CF, concentration in fly ash; CB, concentration in bottom ash) for analyte elements were used to evaluate the partitionings of the elements between fly and bottom ashes. Then, the correlations between the CF/CB values of the elements and the dissociation energies of their monoxides were examined to evaluate the kinetic behaviors of the elements during the incineration processes. It was found that lithophile and siderophile elements, which have a large affinity with oxygen, were almost equally distributed between fly and bottom ashes, regardless of the dissociation energies of their monoxides. On the other hand, chalcophile elements with rather large volatility provided different behaviors; the elements with the smaller dissociation energies of monoxides were more partitioned in fly ashes than those with the larger ones.     

Instrumental neutron activation analysis of fly ash,aerosols and hair

Samples of coal, slag, emissions retained on the separating devices, fly ash, aerosols and hair taken in the area of coal-fired power plant were analyzed by means of instrumental neutron activation analysis. 13 to 23 elements were determined in the samples. The data obtained for emissions and aerosols were further evaluated by calculation of enrichment factors, correlation coefficients and by the ratio matching method. The concentrations of elements determined in the hair of exposed group were compared with the data of control and out control groups as well as with the recent data found for hair in other countries. It can be seen from the results that arsenic is the most serious pollutant in the area.     

Variability of total and mobile element contents in ash derived from biomass combustion

Seven samples of the ash derived from biomass, representing both fly and bottom ash, were analysed for a wide spectrum of total and mobile contents of nutrient and potentially risk elements. Several techniques, X-ray fluorescence (XRF) spectrometry, instrumental neutron activation analysis (INAA), proton-induced gamma-ray emission (PIGE) and proton induced X-ray emission (PIXE), inductively coupled plasma-atomic emission spectrometry (ICP-OES), and flame atomic absorption spectrometry (F-AAS) were compared. The results showed fairly good agreement between the XRF and INAA results, where the correlation coefficients (r) varied between 0.96 and 0.98. Lower contents documenting insufficient dissolution of the ash samples in the applied acid mixture were observed for both ICP-OES and AAS. In this case, weaker correlation with the INAA results not exceeding r = 0.7 were obtained. Therefore, the sample decomposition step is a bottleneck of the accurate analysis of this type of materials. For the assessment of plant-available portions of the elements in the ash samples, the Mehlich III extraction procedure and the extraction with a 0.11 mol L^?1 solution of CH₃COOH were applied. The results showed relatively low mobility of the elements (especially micronutrients) in the ash samples regardless of their source and composition, suggesting limited immediate effect of direct ash application as a fertilizer.     

Separation of Palladium by Extraction Chromatographic Technique Using Cyanex 471X (Tri Isobutyl Phosphine Sulfide) on Chromosorb-102

In a preliminary study performed with the waste rocks from the future uranium mine to be explored in Brazil, 106 samples were taken from the eight main lithologies found in the massif and analysed by instrumental neutron activation analysis (INAA) for 20 elements. For samples from the same lithology, a high variability in the concentration of most of the elements was found (coefficient of variation larger than 20%), which might be attributed to either insufficient homogenisation of minerals or to local variation within lithology. The hypothesis that the variability within the lithology does not have an influence to the total variability was tested by analysing 5 replicates of the 5 most contrasting samples from the predominant lithology (plagioclase-microcline-gneiss), chosen after applying statistical evaluation (principal components and cluster analyses). Results indicated that homogenisation of samples was adequate due to low variation among replicates. The hypothesis tested was rejected with a confidence level higher than 99% for all the elements, corroborating the large intra-lithology variability.     

Total reflection X-ray fluorescence analysis of fly ash from Bulgarian coal-fired power plants

The contents of Cl, Ca, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ba and Pb in raw coal fly ash from five Bulgarian power plants were determined by total reflection X-ray fluorescence (TXRF), using gallium as the internal standard. The samples were analysed as in slurry form in Triton? X-114. The experimental parameters, such as grain size, concentrations of fly ash slurry and excitation time were optimised. For validation of the method, the certified reference material BCR-176R fly ash was used. The precision of the results obtained is characterised by a relative standard deviation of approximately 10%. The resulting data confirm the suitability of TXRF for the simultaneous determination of major, minor and trace elements in coal fly ash samples. Further advantages provided by TXRF are easy sample preparation (no sample dissolution) and the small sample amount required for analysis.     

Trace elements of coal,coal ashes and fly ashes by activation analysis with short-lived nuclides

On irradiation with neutrons, some of the interesting trace elements in coal, coal ash and fly ash produce short-lived nuclides which may be determined—together with some of the matrix elements—by activation analysis. This enables the characterization of samples. To find out the distribution of elements in the gaseous or aerosol exhaust of fossil-fired power plants, we simulated the combustion in a quartz apparatus containing a cold trap, using the combustion temperature (780 °C) employed for the standard ash determination. High Se values were found in the cold trap deposits from black coal from Poland. Halogens were also found in the deposits.     

Neutron activation analysis and radioactivity measurements of Australian coals and fly ashes

Forty elements were determined by instrumental neutron activation analysis in a wide range of Australian coals and fly ash to update and extend earlier measurements. The natural radioactivity content of selected samples were analysed by high resolution gamma-ray spectrometry and low level radiochemistry. The results indicated a marked disequilibrium of the²³²Th decay series in some samples while a general enrichment of²¹⁰Pb in most fly ash samples disrupted the²³⁸U equilibrium.     

Neutron activation analysis of bottom and fly oil ashes

The concentrations of 25 elements in 7 oil ash samples were determinedby computerized systematic instrumental absolute neutron activation analysis.In the oil ash samples, the following mean concentrations (in ppm) of elementswere found: Al: 39531, As: 109, Ba: 1391, Ca: 29701, Ce: 295, Co: 1294, Cr:1485, Cs: 7.9, Dy: 4.5, Eu: 1.2, Fe: 53094, Ga: 146, Hf: 2.2, La: 1534, Mn:547, Na: 40277, Sb: 360, Sc: 2.3, Sm: 21, Sr: 674, Ta: 15.8, V: 130548, W:4.1, Yb: 0.9 and Zn: 3125. These findings were compared with the concentrationsof elements found in coal ash samples. The concentrations of Co, Na and Vwere significantly higher in the oil ash samples, while the concentrationof Sc was lower. The purpose of this study has been to determine the backgroundlevels of different elements in oil ash, in order to evaluate its potentialimpact on the environment.     

The Stability of Precipitation Samples under Field Conditions

Abstract

Eight wet-only samplers. placed in one location were used to sample precipitation. Subsamples were taken from the sample bottles directly after the precipitation event and at regular intervals up to a period of 2100 hours and analysed, while the samples stayed in the samplers under field conditions.

Outliers were deleted by means of conventional statistical techniques. The resulting data base was tested by means of the F-test for consistency and for changes in the chemical composition of precipitation samples directly after sampling or after an extended stay under field conditions. Eighty-one percent of the samples showed consistent results and no clear indication of chemical changes was found.

Regression analysis indicated that the uncertainties for samples analysed after 1 week are less than 5% generally for the bulk elements and less than 14% for the trace elements. After a period of 400 hours the uncertainties for the buld elements increase to a level of 5–10% and 5–30% for the trace elements.

Contamination, as a result of handling the samples to obtain subsamples, seems the main cause for the increase of the concentrations which was observed.

Contamination during sample pretreatment and analysis in the laboratory is probably of minor importance.     

Neutron activation analysis and natural radioactivity measurements of lignite and ashes from Megalopolis basin,Greece

Elemental concentrations and specific activity values of natural radionuclides were measured in lignite, bottom ash and fly ash samples collected from the Megalopolis power plant A in southern Greece, using nuclear analytical techniques. The results show that the elements As, Br, Mo, Sb, Se, and U were enriched in the lignite samples, the elements Mo, Se and U in bottom ash, while fly ash samples were enriched in As, Mo, Sb, Se and U. Specific activity measurements also show that ²³⁸U (²²⁶Ra) activity values in lignite and both ash samples were high relative to the corresponding data for coal and earth crust given in the literature. As a high quantity of fly ash is produced during the operation of the lignite power plant A, this power plant should be considered as a major source of air particulate pollution and radiation to the population living in the vicinity of lignite burning power plant.     

Atmospheric toxic metal contributions from hospital incinerators

Air particulate samples taken downwind of two Toronto hospital incinerators analyzed by neutron activation analysis (INAA) and proton-induced X-ray emission analysis (PIXE) were subjected to factor analysis and chemical element balance to identify various emission sources and their contributions to the amibient aerosols. Hospital incinerators, contributing 22–36% to the ambient aerosols, were the major anthropogenic source at the receptor sites studied. Elevated concentrations of Ag, Cd, Cl, Cr, Sb and Zn were found in the hospital incinerator ash samples. Studies of the elemental concentrations of disposable hospital plastics and their fates during combustion indicate that these toxic elements found in the hospital waste and stack emissions are partly attributable to the extensive use of plastics in hospitals.     

Dry-Ashing Preconcentration for Micro-Reactor-Based Neutron Activation Analysis of Food and Plant Samples

The application of preconcentration by dry-ashing to the neutron activation analysis of biological samples using a SLOWPOKE-2 low-power reactor is reported. Samples of selected food crops (banana, callaloo, carrot, mango, and yam) and bioindicator plants (lichen, moss, Tillandsia sp., and tree bark) were analysed both as plant tissue, and as ashed sample. The results are presented for 21 elements. Good agreement between both procedures (<10% relative standard error) was obtained for 13 elements: Al, Ca, Cd, Cr, Fe, K, La, Mg, Mn, Na, Sm, Ti, and V. For Dy, Rb, and Zn the agreement was 10-15%. Relatively poorer agreement (>15-30%) was obtained for As, Br, Cl, and Sb. Dry ashing produced improved analytical results for those samples that were of low ash content. However, the increased background counts observed in ashed samples can sometimes negate the concentration gain, particularly in plants with high ash contents but low levels of certain elements.     

Direct analysis of fly ash materials by inductively coupled plasma atomic emission spectrometry using slurry nebulization

Fly ash samples of cement works were analysed using slurry nebulization inductively coupled plasma atomic emission spectrometric (ICP-AES). Because of the influence of the experimental factors on the signal intensity, the optimal conditions of the analysis circumstances were determined. Control analyses (wet digestion followed by ICP-AES, and XRF of dry powders (pressed pellets)) were also carried out to compare the results. Based on the result, it was concluded that the slurry nebulization method using slurry standard of same type reference material for calibration can be applied for rapid but less precise (RSD 5–10%) determination of the elements in fly ash.     

煤中有害元素的洗选洁净潜势

基于8个洗煤厂实采煤样的测试分析以及2个煤样的模拟洗选实验，对煤炭洗选过程中灰分、硫分及20种有害微量元素的脱除率进行了研究，并系统地探讨了这些有害元素的洁净潜势。结果表明：物理洗选不但能降低煤中的灰分与硫分，还能不同程度地脱除煤中有害微量元素；预测在物理洗选过程中，多数煤中灰分以及有害微量元素As、Co、Cu、Cr、Hg与Mn的脱除率大于50％，硫分的脱除率大于30％，其它有害微量元素Ba、Be、Cd、Cl、Mo、Ni、P、Pb、Sb、Se、Th、U、V与Zn的脱除率相对较低或表现出一个宽的变化范围。     

INAA multielemental analysis of Nigerian bituminous coal and coal ash

Instrumental neutron activation analysis (INAA) was used to analyzed Nigerian bituminous coal and ash. Good statistical agreement (p0.05) between the literature and reported elemental values of USGS AGV-1 sample was found. Many elements were determined in the coal with some enrichment in the coal ash. Arsenic was measured only in the ash while Hg was present only in the coal. Coal ashing at 800°C contributed to a loss of Hg in the ash. Al, Na, Mg, Ti, Fe, which are major elements were found in the coal as expected, with slight enrichment in the ash. Ca and Si were only obtained in the ash. High ash Al (14.9±0.19%) and Si (25.3±4.11%) levels are of concem due to possible cases of pneumononiosis from inhalation of the particulates. Graphical illustration of the lanthanide concentrations peaked at Ce with a decrease from Sm to Lu. U and Th were also present in the samples showing slight enhancement in the ash. Comparatively low coal elemental values, notably S(1.8%), highly advocate this coal as a good quality fuel-coal.     

城市污水污泥与固体垃圾混烧过程中重金属迁移特性的研究

通过城市污水污泥与固体垃圾合成样品在小型管式焚烧炉内的混烧实验,采集灰渣样品进行XRF化学成分分析和浸出毒性鉴别测试,结合污水污泥焚烧过程中热力学平衡计算,定量表征了污水污泥中Cu、Pb、Zn、 Mn、Ni在焚烧过程中向底灰、飞灰和烟气迁移的特性及对灰渣的毒性影响。研究结果表明,污水污泥混烧显著提高了飞灰和底灰中重金属含量,其中Zn和Pb增加量最大,而Ni、Mn、Cu依次减少;随着有机氯的加入,飞灰中重金属含量呈现递增趋势,其中Zn表现最明显。毒性测试结果显示,污水污泥的混烧也导致了垃圾焚烧飞灰中Zn和Pb的浸出浓度超过中国对危险废物浸出的控制标准值。同时,重金属迁移的热力学平衡模型预测结果与实验结果差距较大。这表明热力学平衡计算方法还需进一步考虑影响重金属氯化物形成的其他因素,如在焚烧过程中反应动力学、焚烧室内氧气含量变化、与其他元素间的化学反应等。     

A Sequential Extraction Method Measures the Toxic Metal Content in Fly Ash from a Municipal Solid Waste Incinerator

The purpose of this research was to develop an optimized pretreatment procedure for toxic metals (Pb, Cd, Zn and Cu) content in fly ash from a municipal waste incinerator. In addition, modified sequential extraction procedures were used to characterize the chemical composition of the fly ash samples. The sequential extraction resolved the fly ash elements into the following chemical forms: soluble, exchangeable, carbonate, oxide, organic, and silicate compounds. Certified reference city waste incineration ash (BCR.176) was used as target ash samples. A H₂O₂+HNO₃+HF mixed acid digestion solution with a low temperature evaporation procedure was selected as optimal for the fly ash digestion. The digested solution was analyzed by inductively coupled plasma mass spectrometry (ICP‐MS), which effectively determined the concentrations of the toxic metal elements in BCR.176. Except for Cd, the recovery of Pb, Zn, and Cu under H₂O₂+HNO₃+HF digestion and their sequential extraction procedures were higher than 95%. The relative standard deviations (RSD) for recoveries of the four elements were within 10%. Furthermore, the sequential extraction procedure's results provided information on the potential mobility of the studied elements. Most of the Cd was bound to water‐soluble and carbonate material in the fly ash samples. Most of the Pb, Zn, and Cu was released to carbonates and bound to organic matter in the fly ash samples.     

垃圾焚烧飞灰基本特性研究

以三个正在运行的垃圾发电厂的除尘器飞灰为研究对象,实验测出它们的化学组成、热灼减率、灰熔点等物化特性和浸出毒性、腐蚀性等有害特性,对三种灰样的特性进行了对比、分析。结果表明,飞灰的物化特性主要受飞灰中MgO、CaO、SiO2和CaCl2等几种主要成分质量分数的影响。MgO和Al2O3质量分数较高而CaCl2质量分数较低的飞灰其灰熔点相对较高;CaO和CaCl2质量分数较高的飞灰其水分和热灼减率也相对较高;SiO2质量分数较高的飞灰其重金属的浸出率相对较低;CaO和Al2O3等碱性氧化物质量分数较高的飞灰其浸出液的pH值相对较高。     

电感耦合等离子体质谱法分析粉煤灰漂珠中的微量元素

建立了一种电感耦合等离子体质谱法测定粉煤灰漂珠中微量元素的方法,检出限为0.002~0.01 ng/mL,相对标准偏差为1.4%~2.5%(n=10)。用该方法分析了标准物质(GBW 07103)和德州、衡水的粉煤灰漂珠样品中的微量元素,标准物质分析结果与参考值一致,实际样品加标回收率为87.9%~105.6%。