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

Abstract

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.

Pyrolysis-gas chromatography/mass spectrometry of a coal extract and its fractions separated by planar chromatography: correlation of structural features with molecular mass

“…For example, tetrahydrofuran (THF) gives rise to selective adsorption of sample molecules on the column packing and the chemical structure dependence of elution times is well documented 28. In the present calibration, the permeation (low molecular mass) limit of the column has been observed to remain consistent for all samples examined, including biomass tars and petroleum‐derived materials,1,, 2,, 3,, 14,, 16,, 31–33 indicating the absence of surface adsorption effects. However, our findings showing the relative independence of elution times from structural features2,, 3 differ from those of Lafleur and Nakagawa30 who (using NMP as eluent but an apparently different column packing) reported significant dependence of elution times on structural variations in sample molecules.…”

Elution of Ti during solvent extraction of coal and the transformation of eluted Ti upon combustion

“…[9][10][11] Recent studies have been extensively conducted on the elution of most the elements and their properties in coal extract. [12][13][14][15][16] Information for Ti is, however, scarce.…”

“…), and B and Hg, as well as ion-exchangeable ions like Ca and Mg, are preferentially extracted. [12][13][14][15][16] Such a case should apply to the organo-Ti as well. Nevertheless, the probability for elution of Ti mineral species cannot be ruled out.…”

Product Characterization for Entrained Flow Coal/Biomass Co-Gasification

“…The results of that report, as well as others [21][22][23] demonstrate that acid digestion methods in combination with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS) are suitable for analyses of the above mentioned elements. Based on the results of the literature studies, as well as the significant expertise in chemical and elemental analysis developed by GE Global Research, the ICP-AES and ICP-MS methods with appropriate sample digestion methods were applied in the program to determine the minor and trace metal concentrations in the fuel samples and gasification products.…”

“…In coal, many trace elements are mostly associated with mineral matter, are not easily volatilized, and tend to be relativelyinert during gasification. However, in biomass many trace elements are associated with the organic matrix and are readily released during gasification [14,21,22]. If the formation of solid phase is thermodynamically favorable, the released trace elements may re-condense immediately on existing solid particles.…”