Ⅰ. INTRODUCTION Humic acid and fulvic acid are natural acidic products with aromatic character and polydispersive properties. In our previous works, fulvic acids extracted from two different kinds of weathered coals ...Ⅰ. INTRODUCTION Humic acid and fulvic acid are natural acidic products with aromatic character and polydispersive properties. In our previous works, fulvic acids extracted from two different kinds of weathered coals were fractionated by solvent gradient fractional elution method to obtain a series of fractions with increasing molecular weights.展开更多
文摘Ⅰ. INTRODUCTION Humic acid and fulvic acid are natural acidic products with aromatic character and polydispersive properties. In our previous works, fulvic acids extracted from two different kinds of weathered coals were fractionated by solvent gradient fractional elution method to obtain a series of fractions with increasing molecular weights.