Efficiency of chemically modified low cost adsorbents for the removal of heavy metals from waste water: a comparative study.

In this paper, a comparative study of removal efficiency of heavy metals [copper Cu(II), Manganese--Mn(II), Iron--Fe(II), Nickel--Ni(II), Lead--Pb(II) and Zinc--[Zn(II)] from aqueous solution by adsorption on non-conventional materials and on chemically activated non-conventional materials, is presented. It is found that the adsorption potential varies as a function of contact time, concentration, particle size, pH and flow rate. Of all the low cost adsorbents used in the study, saw dust is found to possess greater adsorption efficiency for all metals, than rice husk under identical experimental conditions. Chemically activated saw dust could remove 98.28% of Cu(II); 100% of Mn(II); 96.72% of Fe(II); 96.72% of Cd(II); 75% of Cr(VI); 80% of Ni(II); 95% of Pb(II) and 93% of Zn(II), from the corresponding metal solution taken one at a time.