Prof. Hassan Hamza Abbas Ramdan :: Publications:

The present work aimed throwing some light on chemical behavior of montmorillonite clay mineral (Mont.), calcium carbonate (CaCO3) and humic acid (HA). These materials are used as additives to soil for minimizing bio-availability of heavy metals in soils and hence reducing their potentially hazards risk. Because Ni is found in soil due to some anthropogenic sources and may cause hazardous effects on the plant grown thereon, reducing of its availability by retention with the aforementioned additives was the main target of the current work. Different concentrations of Ni were equilibrated with Mont., CaCO3 and HA under different pH values. Retained amounts of Ni were calculated as the differences between the applied Ni concentrations and the corresponding remained concentrations in the solution. Both Van-Bemmelen-Freundlich and Langmuir isotherm equations were used for describing the relationship between the adsorbed amount of Ni per unit weight of the adsorbent and concentration of Ni in the equilibrium solution. Results revealed that the amounts of Ni adsorbed by the examined increased gradually with increasing concentrations of Ni in the equilibrium solution under the different studied pH values. Also, adsorbed amount of Ni per unit weight of the different studied adsorbents increased with increasing the pH values. The examined materials revealed different sorption capacities for Ni according their nature and ambient pH value. Also, the examined materials showed different adsorption maxima as well as different affinities for Ni at the different pH values. It could be concluded from the obtained results that application of additives such like those investigated herein may be helpful in ameliorating soils contaminated with heavy metals such as Ni through changing most of its available content to retained (unavailable) content and hence limiting its transport to plant and consequently the food chain.