ATOMIC FORCE MICROSCOPY (AFM) STUDY OF THE ADSORPTION OF SOIL HA AND SOIL FA AT THE MICA-WATER INTERFACE

Adsorption of humic molecules on clay minerals improves their geochemical stability and provides an active surface for cation exchange and sorption of organic compounds.'" The importance of clay-humic complexes in contaminant binding and transport has been demonstrated:-" Experimental data suggest that the interaction between humic substances and clay particles influences the conformation of the humic molecules and consequently the sorptive properties of the clay-humic complex.' Structural information about clay- humic complexes is needed to design appropriate models for clay-humic complex formation and stability under diverse environmental conditions and to understand the sorption of ions and molecules on clay-humic complexes.