Removal of heavy metals through adsorption using sand.

The removal of four heavy metals i.e. Pb, Cr, Cu, and Zn from their aqueous solutions, using ordinary sand as an adsorbent, was studied at 20 degrees C. The amount of metal adsorbed to form monolayer on sand (a(m)), obtained from Langmuir isotherm, exhibited the preference of metals for sand in the order Pb > Cr > Cu > Zn. The heavy metal-sand adsorption phenomena can be illustrated on the basis of the interaction between surface functional group of silicates (sand) and the metal ions. It is deduced that sand can be used as a low cost adsorbent for the removal of heavy metal from wastewater (containing low conc. of metals), especially in the developing countries.