The basic structure of humic acid macromolecules is aromatic ring and aliphatic ring, and functional groups such as carboxyl group, hydroxyl group, carbonyl group, quinone group and methoxy group are connected to the ring. It has exchange, adsorption, complexation and chelation with metal ions; As a polyelectrolyte in dispersion system, it has the functions of coagulation, peptization and dispersion. Humic acid molecules also have a certain amount of free radicals, which have physiological activities.
Modified humic acid refers to humic acid from various sources after chemical treatment (such as oxidation, sulfonation, degradation, halogenation, nitration, polycondensation, ammoniation, amidation, etc. (Generally, humic acid should be extracted before modification).