The pollution by heavy metals currently is becoming a big challenge and a concern for the water quality and also for the environment in general. Some metal ions are toxic even if their concentration is very low and their toxicity increases with accumulation in water and soils. Several industrial wastewater streams may contain heavy metals such as, Pb, Cr, Cd, Ni, Fe, Mn as well as Zn, As, Hg, Cu and Ag. The clays have been extensively utilized for the removal of heavy metals from aqueous

more »

... ns. The aim of this research work was to prepare acid activated bentonite clay by using H 2 SO 4 and C 2 H 4 O 2 as acid chemical reagents. The adsorption capacity of natural and acid activated bentonite clay with iron and manganese was also investigated. The removal of two heavy metals was studied at 25 °C. Both modified forms showed higher adsorption efficiency than the natural clay. Moreover, the empirical values were evaluated according to the Freundlich isotherms that are generally used to describe the adsorption processes. The heavy metal-clay adsorption phenomena can be illustrated on the basis of the interaction between surface functional group of silicates (clay) and the metal ions. It is deduced that clay can be used as a low cost adsorbent and locally available for the removal of heavy metals, especially in the developing countries.