2018 Volume 97 Issue 4 Pages 88-96
In order to develop an efficient pre-desulfurization technology for both inorganic and organic sulfurs in coals under the mild condition, oxidative desulfurization using hydrogen peroxide was carried out for five kinds of coals with different rank. The coal samples were agitated in the hydrogen peroxide aqueous solution for 2 h at the room temperature. Pyritic sulfur and sulfate as the inorganic sulfur were removed completely from the solid phase by the treatment. Organic sulfur was simultaneously removed, for example, 84% of organic sulfur was reduced for a low rank coal. The removed sulfur from the solid phase dissolved in the hydrogen peroxide aqueous solution as sulfate. XANES analysis showed that thiophenic sulfurs in the coals changed to sulfoxide and sulfone during the hydrogen peroxide treatment. The removal extent of thiophenic sulfur decreased with the increase of the coal rank and correlated well with the aromaticity of the raw coals.