Efficiency and mechanism of lead stabilization in soil of lead-acid battery contaminated site with phosphorus-based materials
<p>Lead contaminated soils occurred at lead-acid battery manufacturing and recycling sites are of great concern. Bench-scale batch experiments of stabilization treatment were conducted using twelve materials and three phosphorus-based materials, KH<sub>2</sub>PO<sub>4</sub>(KP), KH<sub>2</sub>PO<sub>4</sub>:oyster shell power = 1:1 (by mass ratio; KSP), and KH2PO4:sintered magnesia = 1:1(by mass ratio; KPM), were screened out for lead contaminated soil in an abandoned lead-acid battery factory site. The three materials had higher remediation efficiencies that led to a 92% reduction in leachable Pb and 12% reduction in bioaccessible Pb with the addition of 5% material, while the acid soluble fraction of lead decreased by 41&#8211;46%. The lead activity in the soil solution sharply decreased treated by three materials. Pb<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>Cl was the primary mineral controlling lead solubility in soil treated by KP and KSP and lead activity was related to Pb<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH and Pb<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>Cl in soil amended with KPM.</p>