Characteristics of Humic and Fulvic Acids Extracted from Weathered Coal of China

摘要

Basic characteristics of humic acid (HA) and fulvic acid (FA) extracted from three kids 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 functioal 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 fropm weathered coal was somewhat lower than for the FA from peat and soil.