X-ray photoelectron spectroscopy study of oxidized coals with different sulphur content

• Published in: Fuel processing technology Vol. 77; pp. 1 - 7
• Main Authors: Grzybek, Teresa, Pietrzak, Robert, Wachowska, Helena
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 20.06.2002; Elsevier Science
• Subjects: Applied sciences; Coal; Coal and derived products; Energy; Exact sciences and technology; Fuel processing. Carbochemistry and petrochemistry; Fuels; Oxidation; Oxidized sulphur species; Solid fuel processing (coal, coke, brown coal, peat, wood, etc.); Structure, chemical and physical properties; XPS; Oxidation; XPS; Oxidized sulphur species; Coal; Sulfur compounds; X ray spectrometry; Sulfoxide; Photoelectron spectrometry; Thiophene; Sulfonic acid; Coal rank
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/S0378-3820(02)00058-9

The aim of the study reported was to determine the effect of oxidation on the surface composition of coal as studied by X-ray photoelectron spectroscopy (XPS) method. Five coals characterized by a different degree of coalification and different amounts of sulphur were subject to oxidation with peroxyacetic acid (PAA). The process of oxidation was carried out for coal samples demineralised by the Radmacher method. Carbon, oxygen, sulphur and nitrogen peaks were registered and analysed. The effect of oxidation depended on coal rank. In case of S 2p, three or four peaks were found for the oxidized samples, corresponding to tiophene, sulphoxides (Ph 2–SO type), sulphonic acids and in some cases, more oxidized forms of sulphur, possibly inorganic sulphates. The surface sulphur content increased upon oxidation. A possible reason could be the mobility of the S-containing species.