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Wyszukujesz frazę "Lignites" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Sugars in environmental samples and sedimentary rocks : effectiveness in derivatization for GC-MS analysis
Autorzy:
Smolarek-Lach, Justyna
Goryl, Magdalena
Marynowski, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/2060100.pdf
Data publikacji:
2021
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
BSTFA
MSTFA
particulate matter
fungi
lignites
Opis:
Saccharides (sugars), common constituents of the bio- and geosphere, are useful in determining the source of organic matter (OM) in aerosols and early diagenetic phases. Due to the chemical properties and great diversity of sugars in nature, a wide range of techniques is used for the isolation and quantification of saccharides. Here, gas chromatography-mass spectrometry analysis, preceded by derivatization with N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), was undertaken. The effectiveness of this derivatization was demonstrated for soils, aerosols, fungi, and individual sugar standards. The efficacy of BSTFA derivatization for individual sugar standards and, similarly, for samples of sugars in winter and summer aerosols was adequate. In fungi and soil samples, the MSTFA reagent was much more effective. Different mono- and disaccharides were identified in biological samples and sedimentary rocks, showing not only the great diversity of these compounds but also the specificity of their origin in recent and ancient OM. Greater variation in the occurrence of sugars in soils compared to rocks may suggest differences in the stability of some saccharides at an early stage of diagenetic transformation. Comparison of the occurrence of certain sugars in biological samples and sedimentary rocks sheds new light on the origin and preservation of these biomolecules.
Źródło:
Geological Quarterly; 2021, 65, 3; 65: 40
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Petrological studies of low temperature oxidation of lignites
Autorzy:
Markova, K.
Stefanova, Y.
Boneva, M.
Powiązania:
https://bibliotekanauki.pl/articles/1204921.pdf
Data publikacji:
2002
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
lignites
lithotypes
oxidation
East Maritza Iztok basin
Opis:
The low temperature oxidation processes which has taken place in lignites and their lithotypes (xylain, humovitrain, semifusain, fusain and liptain) from the East Maritza basin have been studied. The changes occurring in the coals/lithotypes composition and structure during their oxidation have been followed by examining reflectance, microhardness, proximate, ultimate, functional, and increment analyses. The main kinetic parameters such as duration of the induction period, maximum and stationary rates and the apparent activation energies were evaluated. The complex investigation provides a detailed information for the behaviour of low rank coals and their lithotypes towards the action of atmospheric oxygen. Thus some suggestions concerning the mechanisms of their oxidation reactions can be made. The individual way of the genesis of each one of the lithotypes and the resulting physicochemical structure predetermine the basic mechanism of these reactions. However, it has been found that in spite of the similar genesis the lithotypes differ in the mechanism of their oxidation. For xylain the oxidation takes place mainly via aryl radicals yielding tertiary peroxide and carbonyl groups. The oxidation of humovitrain is characterised by the dominant participation of aroxyl radicals resulting in accumulation of primary hydroperoxide and phenol groups. The oxidation of semifusain leads mainly to the formation of molecular products. The oxidation of fusain is found to be essentially different from that of other lithotypes. It is characterised by the formation of carbonyl groups attached to biphenyl aromatic structures. The peculiar petrographic composition and structure of liptain account for the occurrence of oxidation processes accompanied by destruction reactions at relatively lower temperatures. It has been established that the intensity of the oxidation processes varies from one lithotype to an other. Xylain and humovitrain oxidise most intensively. The intensity drops off from the first towards the second member of the corresponding genetic series, i.e. from xylain to humovitrain and from semifusain to fusain.
Źródło:
Polish Geological Institute Special Papers; 2002, 7; 159-168
1507-9791
Pojawia się w:
Polish Geological Institute Special Papers
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical characterization and palaeoenvironmental implications of lipids in Neogene lignites and lignitic shales in NW Poland
Autorzy:
Czechowski, Franciszek
Polowczyk, Marzena
Simoneit, Bernt R. T.
Grelowski, Cezary
Hojniak, Marek
Powiązania:
https://bibliotekanauki.pl/articles/27311291.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Lignites
biomarkers
n-alkanes and isoprenoids
diterpenoids
triterpenoids
polycyclic aromatic hydrocarbons
Opis:
The lipophilic biomarker distributions in lipids of Neogene lignites and lignitic shales in western Pomerania and the midlands of Poland are presented. Twenty-six lignite samples and seven lignitic shales were obtained from twenty-four boreholes. Their extracts were separated, using thin-layer chromatography, and the saturate and aromatic fractions were analyzed by gas chromatography-mass spectrometry. The molecular compositions of n-alkanes, isoprenoids, n-alkylcyclohexanes, n-alkylbenzenes, tri- and tetracyclic diterpenoids, pentacyclic triterpenoids, as well as polycyclic aromatic hydrocarbons (PAHs) with up to five rings, were determined. The samples displayed n-alkane distributions in the range of C14–C35 and high odd-over-even carbon number predominances (CPI(25–33) from 2.9 to 7.9). Diterpanes consisted primarily of phyllocladane, abietane, isopimarane, labdane, and kaurane structures, although their abundances varied among the samples. Hopanes exhibited the biological and geochemical characteristics of low-maturity organic matter. Minor oleanane triterpenoids from angiosperms were also found. A few samples displayed evidence of biodegradation on the basis of the advanced isomerization of αβ-hopanes and the presence of short-chained n-alkanes, n-alkylcyclohexanes, and n-alkylbenzenes. A more mature stage of the above biomarkers also may have resulted in part from the oxidation of organic matter. The lignite source materials were derived from conifer and angiosperm flora as well as microbial remnants. The contribution from marine phytoplankton was excluded on the basis of the lack of C27 steroids. PAHs were predominantly perylene or phenanthrene, with minor other analogues. Thus, the data support progressive lacustrine/lagoonal sedimentation in the palaeoenvironmental mires.
Źródło:
Annales Societatis Geologorum Poloniae; 2023, 93, 4; 447--466
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of hazardous air pollutants based on commercial coal preparation plant data
Autorzy:
Ozbayoglu, G.
Powiązania:
https://bibliotekanauki.pl/articles/109309.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hazardous air pollutants
coal preparation
Turkish lignites
trace elements rejection
dense medium separation
Opis:
This paper investigates the concentration, distribution, and rejection of hazardous air pollutants, specifically identified by the US Clean Air Act Amendments of 1990, based on commercial coal preparation plant data obtained on-site. The samples were collected from the products of the different cleaning circuits of the operating plant. The concentrations of twelve potentially hazardous trace elements, including As, Cd, Co, Cr, Hg, Mn, Ni, Pb, Se, Th and U in those samples were determined. Compared with the average concentration of the trace elements in Turkish coals, the run-of-mine coal fed to the existing plant appears to contain higher concentrations of Cd, Hg, Mn, Th and V. However, the concentrations of As, Cd, Cr, Mn, Se, Th, U and V of the run-of-mine coal are above the world averages. Cd, Cr, Hg, Mn, Pb and Th concentrations of run-of-mine coal were easily removed at commercial coal preparation plant refuse in the range of 51.8% to 77.4 %, while only a small reduction was achieved for U and V as they were concentrated in clean coals. The present study reveals that conventional coal preparation technologies could significantly reduce hazardous air pollutants concentrations in coal.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 2; 621-629
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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