The present investigation was made to study the usefulness of fly ash as an adsorbent to retain hazardous heavy metals. In the present study, a bed of fly ash was prepared in a standard Proctor mould at optimum moisture content and maximum dry density. A solution of chromium sulphate was allowed to pass through this bed of fly ash, with an overnight interruption between two consecutive days of column study, simulating conventional column study experiments in adsorption study. The effluent solution coming out of this bed was collected at intervals of 15 minutes. Subsequently, these samples were analysed to determine the effluent concentrations of chromium, calcium, magnesium, sodium and potassium. The pHs of these solutions were also measured and correlated with the effect of cumulative volume of outflow of treated water. The same experiment was also done using tannery wastewater. Standard breakthrough curves were drawn and analysed. It was found that fly ash has great potential to adsorb hazardous chromium from chrome-bearing wastes, and that fly ash also has potential as a liner to retain this heavy metal.

Land Contamination & Reclamation, 18 (2), 161-173 (2010)