Characteristics of Humic and Fulvic Acids Extracted from Weathered Coal of China
Parida YAMADA, Taeko AKIBA, Yuki YAZAWA and Tatsuaki YAMAGUCHI*
Department of Industrial Chemistry, Chiba Institute of Technology; 2-17-1, Tsudanuma, Narashino-shi 275-0016 Japan
Basic characteristics of humic acid (HA) and fulvic acid (FA) extracted from three kinds of weathered coal of different coal-producting districts (China) by the standard method of International Humic Substances Society (IHSS), were compared with those of already known substances from peat moss (Canada), peat (China), andosol (Japan) and forest soil (Japan), and also an artificial humic acid.
Their compositions and structures were measured by means of their FT-IR and CP/MAS 13C-NMR spectra. It was recognized that regenerated humic acid is formed extensively by the air oxidative degradation of coal under natural environment. The extracted HA from weathered coal has a higher content of aromatic carbon (aromaticity) and acidic functional group (mainly carboxyl group) than those from Canadian peat and forest soil. The content of carbohydrates C is somewhat lower for the HA and FA from weathered coal than for the peat and soil HA, FA. The content of methoxy carbon in the FA from weathered coal was somewhat lower than for the FA from peat and soil.