Multi-Component EPR Spectra of Coals with Different Carbon Content

• Authors: B. Pilawa , A. Więckowski , R. Pietrzak , H. Wachowska
• Languages of publication: EN

Abstracts

EN

EPR spectra of lignite"Mequinenza" (Spain) (62.3 wt% C) and Polish orthocoking coal (87.8 wt% C) were compared. The spectra were superpositions of broad Gaussian, broad Lorentzian 1, and narrow Lorentzian 3 lines. Concentration of paramagnetic centers - mainly delocalizedπ electrons - responsible for narrow Lorentzian 3 lines increases with increase in carbon content in coal. Coal units with slow and fast spin-lattice relaxation processes exist in the two studied samples. Slow spin-lattice interactions occur in simple aromatic coal units with broad Gaussian and Lorentzian 1 lines. Fast spin-lattice relaxation processes are characteristic of large aromatic units with narrow Lorentzian 3 lines.

Keywords

EN

61.66.Hq; 76.30.Rn

Discipline

• 76.30.Rn: Free radicals
• 61.66.Hq: Organic compounds

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2005
• Volume: 108
• Issue: 2
• Pages: 403-407

Dates

published

2005-08

received

2005-04-24

Contributors

author

B. Pilawa

• Institute of Coal Chemistry, Polish Academy of Sciences, Sowińskiego 5, 44-121 Gliwice, Poland

author

A. Więckowski

• Division of Magnetic Resonance Spectroscopy, Institute of Physics, Faculty of Physics & Astronomy, University of Zielona Góra, Szafrana 4a, 65-516 Zielona Góra, Poland

author

R. Pietrzak

• Laboratory of Coal Chemistry and Technology, Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland

author

H. Wachowska

• Laboratory of Coal Chemistry and Technology, Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland

References

• 1. B. Pilawa, A.B. Wieckowski, R. Pietrzak, H. Wachowska, Mol. Phys. Rep., 34, 127, 2001
• 2. B. Pilawa, A.B. Wieckowski, R. Pietrzak, H. Wachowska, Fuel, 81, 1925, 2002
• 3. W. Radmacher, P. Mohrhauer, Brennstoff-Chemie, 37, 353, 1956
• 4. R. Pietrzak, H. Wachowska, Fuel, 82, 705, 2003
• 5. B. Pilawa, A.B. Wieckowski, B. Trzebicka, Mol. Phys. Rep., 4, 245, 1994
• 6. B. Pilawa, A.B. Wieckowski, B. Trzebicka, Radiat. Phys. Chem., 45, 899, 1995
• 7. B. Pilawa, B. Trzebicka, A.B. Wieckowski, Fuel, 70, 1109, 1991

Identifiers

DOI

10.12693/APhysPolA.108.403