Lead Sorption from Aqueous Solution Using Apatite and Residue Ash Recovered from Sewage Sludge Ash

Abstract

 This study evaluated the lead sorption ability of apatite and residue ash recovered from sewage sludge ash to use them as a heavy-metal sorption amendment. The level of lead sorption and initial lead sorption rate of the apatite and residue ash were greatly higher than those of the sewage sludge ash, indicating that phosphorus recovery treatment from sewage sludge ash can enhance the capacity of lead sorption. The level of lead sorption enhanced further after dissolution-precipitation treatment of apatite. Lead was sorbed onto residue ash by the precipitation of lead sulfate, which correspond to 66% of total lead sorption. The level of lead sorption of residue ash was increased and the percentage of lead dissolution from residue ash was decreased with pH increase from acid to neutral. The lead sorption abilities of improved apatite and residue ash were equal and/or high compared with other apatites and industrial by-products/wastes, respectively, suggesting that they are probably able to be used as a lead sorption amendment from wastewater.