Single and binary adsorption of heavy metals on fly ash samples from aqueous solution

► Use of fly ash based adsorbents for the removal of heavy metals is proposed. ► Prepared adsorbents exhibited significant adsorption capacities for heavy metals. ► The observed order of single and binary adsorption is Pb(II) > Ni(II) > Cr(VI). ► Lower solution pH favors maximum Cr(VI) adsorption on fly ash based adsorbents. ► About 90% of Pb(II) was removed in 30 minute contact time.