Abstract: A STUDY ON DISSOCIATION AND COMPLEXATION OF FUIVIC ACID FROM WEATHERED COAL USING POTENTIOMETRIC TITRATIONDU JINZHOU；GAO HUANXIN；LUAN XINFU；JING QI；TAO ZzLU CHANGQING（Nanjing Institute of Soil Science, Academia Sinica, 210008）ABSTRACT The dissociation and complexation of fulvic acid from weathered coal（Gong Xian） are stud-ied by means of potentiometric titrations.The effects of salt concentration and functional groupheterogeneity on the apparent dissociation constants are characterized.Some characteristics of thebinding of the ions Cu（Ⅱ），Th（Ⅳ）and La（Ⅲ）on this fulvic acid are determined.Key words Fulvic acid Potentiometric titration Dissociation Complexation