Lead Adsorption by Biomass and Weathered Coal Fly Ashes

Adsorption is an extensively-studied, cost-effective method of removing heavy metal ions from wastewater, such as lead, which is known to be toxic. Removal of metals with adsorbents that beneficially use waste materials are particularly advantageous to study due to their low cost. This research determined the adsorption capacity of three fly ashes (two biomass and one weathered coal ash) for Pb(II) from aqueous solutions. The adsorptive capacity of the alternative ashes were compared to one sample of activated carbon. The biomass fly ashes demonstrated good removal capacity for Pb(II) through a combination of adsorption and precipitation mechanisms. The weathered coal fly ash had low adsorption capacity (less than 3 mg/g). Biomass fly ashes have potential as low-cost alternatives for heavy metal removal.