Influence of Humic Acid on Sorption of Cadmium on Montrmorillonite

The presence of heavy metals and nuclear wastes have raised the level of toxicity in our environment. The dissolved humic substances complicate the migration process of metal pollutants. Humic substances may mask the surfaces of the minerals for reaction with contaminants. Hence, availability and fate of heavy metals in the soil are strongly dependent on the extend of their sorption on hydrated phases. The Present study was focused on the phenomena of retardation of metal migration through the Geosphere by sorption process in a binary as well as a ternary system. Sorption of Cd on clay decreases with metal conc. in a binary system.Similarly metal sorption on HA also decreases with increasing HA concentration in the solution. The sorption of Cd on clay and HA in a binary system was found more significant as compare to the interactions in ternary system.The enhancement in Cd sorption from the aqueous phase in a three component system is not only the result of sorption of free metal ions onto minerals but also the result of chelation with HA sorbed onto the mineral.The distribution of Cd did not simply follow the HA but mineral surface also affected the metal distribution.