Immobilization of chromium and cadmium in contaminated soil using layered double hydroxides prepared from dolomite

Layered double hydroxides (LDHs) were prepared from calcinated dolomite (LDH-D) and used in the remediation of Cd and Cr contaminated soil. The product was fully characterized by Fourier transform infrared spectroscopy, powdery X-ray diffraction analysis and scanning electron microscopy. The results indicate that the LDHs were successfully prepared. The results of remediation tests indicate that a small amount of LDH-D could immobilize the Cr and Cd in the soil. In addition, the effects of pH, LDH dosage, and initial metal concentrations were also evaluated to provide a theoretical basis for the subsequent application of the material in the remediation of contaminated soil. The results such as leaching of toxic metal and phytotoxicity experiments show that LDH-D has a good performance on the fixation of Cr and Cd in soil, preventing the biological transfer of Cr and Cd from soil to plants. Based on different characterization analysis, it is proposed that the main immobilization mechanisms of Cr by LDH-D is surface adsorption. However, for Cd, the formation of CdCO3 and substitution of Mg2+ with Cd in the metal layer is the main removal mechanism.

Automated summary

Layered double hydroxides (LDHs) were used for the remediation of Cd and Cr contaminated soil. The LDHs showed good performance in immobilizing Cr and Cd in the soil, preventing their transfer to plants.