Abstract
The pretreatment of low rank coal with nitric acid oxidation can promote its bio-liquefaction. However, the detailed mechanism of which remains an unresolved problem. In the present work, the characteristics of Fushun coal before and after oxidation by nitric acid were investigated combined with elemental composition, pore volume and pore size, Zeta potential, FT-IR, and 13C solid NMR spectrum analysis. The results show that the inorganic substance inlaid in coal are dissolved by nitric acid, which results in the decrease of coal ash content and increase of pore volume and pore size. Furthermore, there exist obvious chemical reactions between nitric acid and the functional groups of coal including aromatic ring carboxylation, side chain alkyl of aromatic ring oxidation and aromatic ring nitration. Among these reactions, some led to the increase in content of carboxyl, aliphatic carbon connected with O and humic acid carbon, while others caused the reduction of aromaticity, methyl carbon, substituted aryl carbon and side chain.
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Supported by the National Natural Science Foundation of China (50874107); the Guizhou Science and Technology Fund (Qiankehe J zi [2012]2306); the Guizhou High-level Talent Special Assistant Fund (TZJF-2011-04); the Guizhou Research Laboratory Platform of Clean and Efficient Use of Coal Resources (Qianke Platform [2011] 4003)
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Shi, Ky., Tao, Xx., Hong, Ff. et al. Mechanism of oxidation of low rank coal by nitric acid. J Coal Sci Eng China 18, 396–399 (2012). https://doi.org/10.1007/s12404-012-0411-6
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DOI: https://doi.org/10.1007/s12404-012-0411-6