Spectral Studies of Humic and Fulvic Acids of Brown Coals
N. V. MALYSHENKO, S. I. ZHEREBTSOV, K. S. VOTOLIN, N. S. ZAKHAROV, K. M. SHPAKODRAEV, Z. R. ISMAGILOV
Federal Research Center of Coal and Coal Chemistry, Siberian Branch of the Russian Academy of Sciences, Kemerovo, Russia
Keywords: brown coal, humic acids, fulvic acids, IR spectroscopy, EPR spectroscopy
Pages: 505-512
Abstract
Results of investigation into the composition of humic acids (HA) and fulvic acids (FA) isolated from brown coals by means of proximate and ultimate analysis, IR, and EPR spectroscopy are presented. It is shown that the yield of HA exceeds the yield of FA. The maximum yield (60-68 %) was detected for HA from naturally oxidized brown coal. It has been established that lignite FA and HA have significant differences in the structural and group composition: FA are characterized by the higher content of the fragments of aliphatic structures, alcohols, carboxylic acids, and esters. Humic acids are characterized by the higher content of aromatic fragments.
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