Efficiency and mechanism of lead stabilization in soil of lead-acid battery contaminated site with phosphorus-based materials

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, KH₂PO₄(KP), KH₂PO₄: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 41–46%. The lead activity in the soil solution sharply decreased treated by three materials. Pb₅(PO₄)₃Cl was the primary mineral controlling lead solubility in soil treated by KP and KSP and lead activity was related to Pb₅(PO₄)₃OH and Pb₅(PO₄)₃Cl in soil amended with KPM.