Preparation of Fulvic Acid and Low-molecular Organic Acids by Oxidation of Weathered Coal Humic Acid

Abstract

Weathered coal contains much humic acid and a little fulvic acid. Therefore, in this work, the production of fulvic acid, the most valuable humic substance because of its water-solubility, was examined by ozone and hydrogen peroxide oxidation of humic acid extracted form Xinjiang (China) weathered coal. The resulting products of the oxidation were water soluble fulvic acid and organic acids, mainly formic acid and oxalic acid. The product yield of fulvic acid was 20 [C%] and that of organic acids were 39 [C%] for formic and acid 13 [C%] for oxalic acid. The formed fulvic acid showed a higher content of oxygen and carboxyl groups, than those of the extracted one from the original weathered coal.