Extraction of carbonyl, carboxyl functional groups and silicate minerals from coal and its characterization using infrared spectroscopy

Abstract

This paper reports the characterization ond demineralization of coal with HCL, Chloroform and water. The residual cool from each treatment was analyzed using FTIR spectroscopy to understand the effect of chemical leaching and water washing on the sample structure for aliphatic and aromatic CH bonds. Investigation of the mineral content in the sample and its change with above said treatment was also done. Absoptivities for aromatic CH bond stretching and out-of-plane bending modes were found to be independent of the structure. For structural analysis of cool, the structural independence of absoptivities for aromatic CH bonds allows o reliable assessment of aromatic hydrogen content in cools. Evaluation of aliphatic hydrogen content was greatly affected with the presence of chloroform extractable in the cool, which contain highly aliphatic material with a high absoptivities of aliphatic CH bonds, especially those in long methylene chains. The obsoptivities of heteroatom-rich fractions were lower than those of hydrocarbons and did not show any dependence on hydrogen aromaticity of the sample.