Remediation of Pb-Contaminated Soil Using a Novel Magnetic Nanomaterial Immobilization Agent

The management of heavy metal contaminated soil has received extensive research attention. In this study, a novel immobilization agent (SiO₂@Fe₃O₄@C-COOH) was combined with traditional immobilization agents (TIAs), i.e., CaO, organic matter (OM), and calcium superphosphate (CSP), and used to remediate Pb-contaminated soil. The immobilization effects of Pb in soil was evaluated through pot experiments involving wheat cultivation. The results indicated that SiO₂@Fe₃O₄@C-COOH delivered a higher Pb immobilization efficiency than did TIAs such as CaO, OM, and CSP. The application of SiO₂@Fe₃O₄@C-COOH in combination with TIAs (CaO, OM, and CSP) synergistically enhanced the Pb immobilization efficiency of the soil to 85.10%. Further, joint application in a 54.19% reduction of Pb content in wheat roots, a 65.78% reduction in stems, and a 47.96% in leaves. Thus, the combined application of SiO₂@Fe₃O₄@C-COOH and TIAs significantly reduced the bioavailability of Pb, achieved the purpose of Pb stabilization and soil remediation, and has the potential for wide-spread application in the remediation of Pb-contaminated soils.