Czasopismo
Tytuł artykułu
Warianty tytułu
Języki publikacji
Abstrakty
Microwave saturation of multi-component EPR spectra of oxidized lignite Mequinenza (Spain) with a carbon content of 65.1 wt % and with a high sulphur content of 10.3 wt % was studied. The coal was oxidized with nitric acid (NHO3), peroxyacetic acid (PAA), and in O2/Na2CO3 system. Three different groups of paramagnetic centres exist in the coal samples analyzed. The EPR spectrum of the demineralised coal was a superposition of broad Gauss (ΔB pp = 0.75 mT), broad Lorentz 1 (ΔB pp = 0.42 mT) and narrow Lorentz 3 lines (ΔB pp = 0.08 mT). The three EPR components with linewidths: 0.58–0.77 mT (Gauss line), 0.30–0.39 mT (Lorentz 1 line) and 0.05–0.06 mT (Lorentz 3 line) were recorded for the oxidized coal. The g-values were obtained for the samples studied in the ranges 2.0043–2.0046 (Gauss lines), 2.0035–2.0038 (Lorentz 1 lines) and 2.0032–2.0034 (Lorentz 3 lines). The broad Gauss and Lorentz 1 lines saturate at low microwave powers. The narrow Lorentz 3 lines of demineralised coal were not saturated at microwave power from the range considered. After the coal oxidation with HNO3, PAA and in O2/Na2CO3 system, the microwave saturation of the narrow Lorentz 3 lines was also observed, which indicated a degradation of the multi-ring aromatic structures upon oxidation. [...]
Słowa kluczowe
Czasopismo
Rocznik
Tom
Numer
Strony
330-340
Opis fizyczny
Daty
wydano
2007-03-01
online
2007-03-01
Twórcy
autor
- Institute of Coal Chemistry, Polish Academy of Sciences, 44-121, Gliwice, Poland
autor
- Division of Magnetic Resonance Spectroscopy, Institute of Physics, Faculty of Physics & Astronomy, University of Zielona Góra, 65-516, Zielona Góra, Poland
autor
- Laboratory of Coal Chemistry and Technology, Faculty of Chemistry, Adam Mickiewicz University, 60-780, Poznań, Poland, pietrob@amu.edu.pl
autor
- Laboratory of Coal Chemistry and Technology, Faculty of Chemistry, Adam Mickiewicz University, 60-780, Poznań, Poland
Bibliografia
- [1] R.R. Álvarez, C.J. Clemente and D. Gómez-Limón: “Evolution of the organic sulfur and other components during nitric acid leaching of Mequinenza coal”, Fuel, Vol. 76, (1997), pp. 1445–1450. http://dx.doi.org/10.1016/S0016-2361(97)00065-3[Crossref]
- [2] S.R. Palmer, E.J. Hippo and X.A. Dorai: “Selective oxidation pretreatments for the enhanced desulfurization of coal”, Fuel, Vol. 74, (1995), pp. 193–200. http://dx.doi.org/10.1016/0016-2361(95)92654-O[Crossref]
- [3] H. Wachowska, R. Pietrzak and M. Kozłowski: “The Chemical Technology at the Change of the Century”, In: Proceedings of the 3 rd Congress of Chemical Technology, Gliwice, 5–8 September 2000, Wydawnictwo Stałego Komitetu Kongresów Technologii Chemicznej, Gliwice 2000, pp. 519–522.
- [4] B. Pilawa, A.B. Więckowski, R. Pietrzak and H. Wachowska: “Oxidation of demineralized coal and coal free of pyrite examined by EPR spectroscopy”, Fuel, Vol. 81, (2002), pp. 1925–1931. http://dx.doi.org/10.1016/S0016-2361(02)00131-X[Crossref]
- [5] O. Ito, H. Seki and M. Iino: “ESR and FT-IR studies for coal structures. Characteristics of Japanese coals”, Bull. Chem. Soc. Jpn., Vol. 60, (1987), pp. 2967–2975. http://dx.doi.org/10.1246/bcsj.60.2967[Crossref]
- [6] J. Kudynska, H.A. Buckmaster and T. Duczmal: “20°C, 9 GHz CW-EPR saturation measurements of five selected Alberta coals”, J. Phys. III France, Vol. 1, (1991), pp. 1977–1984. http://dx.doi.org/10.1051/jp3:1991244[Crossref]
- [7] T. Grzybek, R. Pietrzak and H. Wachowska: “X-ray photoelectron spectroscopy study of oxidized coals with different sulphur content”, Fuel Processing Technology, Vol. 77–78, (2002), pp. 1–7. http://dx.doi.org/10.1016/S0378-3820(02)00058-9[Crossref]
- [8] W. Radmacher and O. Mohrhauer: “Demineralising of coal for analytical purposes”, Brennstoff-Chemie, Vol. 37, (1956), pp. 353–358.
- [9] H. Wachowska, M. Kozłowski and M. Pietrowski: “Analiza form siarki w polskich węglach kamiennych”, Karbo, Energochemia, Ekologia, Vol. 6, (1996), pp. 199–204.
- [10] Polish Standard PN-77/G-04514.11
- [11] J. Opfermann: Programmpaket Nichtlineare Ausgleichsrechnung, Vol. 42, Friedrich-Schiller-Universität, Jena 1984.
- [12] J.E. Wertz and J.R. Bolton: Electron Spain Resonance. Elementary Theory and Practical Applications, New York, McGraw-Hill Book Company, 1972.
- [13] B. Pilawa, A.B. Więckowski, R. Pietrzak and H. Wachowska: “Multi-Component EPR Spectra of Coals with Different Carbon Content”, Acta Physica Polonica A, Vol. 108, (2005), pp. 403–407.
- [14] B. Pilawa, A. B. Więckowski and B. Trzebicka: “Numerical analysis of EPR spectra of coal, macerals and extraction products”, Radiat. Phys. Chem., Vol. 45, (1995), pp. 899–908. http://dx.doi.org/10.1016/0969-806X(94)E0044-J[Crossref]
- [15] A.B. Więckowski, B. Pilawa, M. Lewandowski, W. Wojtowicz and G. Słowik: “Paramagnetic centers in exinite, vitrinite and inertinite”, Appl. Magn. Res., Vol. 15, (1998), pp. 489–501. http://dx.doi.org/10.1007/BF03162031[Crossref]
- [16] Ya.S. Lebedev: “High frequency ESR: From spectral to spatial resolution”, In: M. Mehring, J.U. von Schütz and H.C. Wolf (Eds.): Extended Abstracts of 25 th Congress AMPERE on Magnetic Resonance and Related Phenomena, Springer-Verlag, Berlin, Heidelberg, New York, 1990, pp. 508–509.
- [17] D.C. Doetschman and D. Mustafi: “The electron spin echo characteristics of several bituminous coals”, In: L. Petrakis and J.P. Fraissard (Eds.): Magnetic Resonance. Introduction, Advanced Topics and Applications to Fossil Energy, Reidel Publishing Company, Dordrecht, 1984, pp. 639–644.
Typ dokumentu
Bibliografia
Identyfikatory
Identyfikator YADDA
bwmeta1.element.-psjd-doi-10_2478_s11532-006-0056-7