Remediation of Pb, Cd, and Cu contaminated soil with Mg‐Fe‐Al layered double hydroxides (LDHs) synthesized from waste red mud

Soils contaminated with multiple heavy metals pose a significant threat to human health and ecosystem functionality. Following a “treat pollution with waste” strategy, we synthesized Mg‐Fe‐Al ternary layered double hydroxides (LDHs) from waste Bayer red mud for the remediation of heavy metal contaminated soils. Characterization using XRD, FTIR, SEM and EDS methods revealed a characteristic layered structure rich in functional groups, offering reaction sites for heavy metal passivation. Passivation experiments showed that the application of Mg‐Fe‐Al LDHs (2.5 wt.%) reduced the availability of Pb (29.7%), Cd (64.1%) and Cu (66.0%) in contaminated soil from a sulphide iron ore area in southern Sichuan Province. Simulated acid rain experiments showed leachate concentrations of Pb, Cd, and Cu reduced by 43.3%, 72.7% and 42.4%, respectively. This work provides a reference for the development of high‐performance and environmentally friendly adsorption‐stabilizing materials for green remediation.