Structural similarity of polymaleic acid (PMA) with soil fulvic acid (FA) may make it a suitable model for soil FA. The adsorption isotherms of PMA on homoionic montmorillonites was L-shaped and the extent of adsorption of PMA on clays was much higher in com#arison to the adsorption of herbicides metoxuron and tebuthiuron. The effect of saturating cations decreased in the order H and trivalent> divalent 3d ions> alkaline earth ions > monovalent ions. The extent of adsorption increased with charge and polarizing power of the fxchange cations. While ion-dipole interactions seem to be dominant in alkali and alkaline eartn cations, ligand exchange seems to be possible mode of interaction for 3d transition metal ipns.
Polymaleic acid, Fulvic acid, homoionic montmorillonites, metoxuron, tebuthiuron
