Remediation of Pb-contaminated soil by magnetic micro-nano size composite MFH

In China, soil heavy metal pollution has become a major environmental problem, posing a serious threat to sustainable development. To remediate Pb-contaminated soil more efficiently, quickly, and inexpensively, a micro-nano-sized (2 μm) magnetic composite (MFH) was prepared. The synthesized materials were characterized by using various techniques such as SEM, TEM, XRD, and VSM. In order to study the reaction mechanism of MFH with Pb(II) in soil, the adsorption of Pb(II) by MFH was investigated. The results showed that MFH had good treatment effects on soils with different levels of lead contamination. The smaller water-soil ratio makes MFH more efficient in treating Pb-contaminated soil. MFH has the best remediation effect on neutral soil with pH = 7, followed by acidic lead-contaminated soil. With the prolongation of treatment time, the removal rate of total lead increased rapidly and reached a relatively stable level in about 8 h, with a total lead removal of 101.05 μg g−1. In addition, the high temperature favored the removal of Pb. However, the increase of ionic strength inhibited the removal of total Pb from the soil by MFH. The Pb(II) adsorbed by MFH material can be recovered by magnetic separation, and the recovery rate can reach more than 88% with good recovery and regeneration ability. In short, MFH is an efficient soil in situ remediation material.