The influence of oxidation with air in comparison to oxygen in sodium carbonate solution on the surface composition of coals of different ranks

The influence of oxidation on surface composition of coals of different rank and different sulphur content were studied. Coal samples untreated or oxidized with oxygen in 0.5 N Na 2CO 3 aqueous solution or air at 125 °C were investigated by X-ray photoelectron spectroscopy XPS. The comparison of sur...

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Bibliographic Details
Published in:Fuel (Guildford) 2006-05, Vol.85 (7), p.1016-1023
Main Authors: Grzybek, Teresa, Pietrzak, Robert, Wachowska, Helena
Format: Article
Language:English
Subjects:
Applied sciences
Coal
Devices using thermal energy
Dryers
Energy
Energy. Thermal use of fuels
Exact sciences and technology
Oxidation
Sulphur
Surface groups
XPS
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Summary:The influence of oxidation on surface composition of coals of different rank and different sulphur content were studied. Coal samples untreated or oxidized with oxygen in 0.5 N Na 2CO 3 aqueous solution or air at 125 °C were investigated by X-ray photoelectron spectroscopy XPS. The comparison of surface O/C ratios with those of the bulk allows to indicate the faster of two competing processes—chemisorption of oxygen or gasification. Where the formation of oxygen containing surface species is concerned, the use of oxygen in gaseous mixtures at moderate temperatures (125 °C) is preferable to oxygen in low temperatures in aqueous media. Mild oxidants such as oxygen in gaseous mixtures at moderate temperatures (125 °C) lead to some decrease in the content of pyritic sulphur. Additionally, relatively small amounts of organic sulphur may be removed in contrast to the application of aqueous solution of peroxyacetic acid which was much more efficient in that matter.
ISSN:0016-2361
1873-7153
DOI:10.1016/j.fuel.2005.09.017