Sorption of Iron and Copper on Sand Bentonite Fly ash Mixtures

Abstract

Compacted clay liners are low cost and effective liners which are promising for retention of
metal ions. An attempt has been made, in this paper, to study the possibility of using a mixture of fine
sand with bentonite or fly ash for retention of metal ions. The retention behaviour of the mixtures for
metal ions of copper and iron has been studied at neutral pH. But it is not easy to carry out the retention
capacities at different pH conditions. The surface adsorption of metal ions is essentially by surface
complexation which varies considerably with pH of the solution. The effect of pH on retention capacities
of sand fly ash or sand bentonite mixtures for copper and iron, was brought out by using Visual Minteq
ver. 3.0 software, as it considers surface complexation as an important phenomenon. Experimental
results have shown that fine sand with 20% bentonite retained higher amount of copper and fine sand
with 10% fly ash retained higher amount of iron respectively. The effect of pH for mixture of sand with
20% bentonite for surface complexation of copper and for mixture of sand with 10% fly ash for iron has
been brought in this paper.