Removal of heavy metals from soil by vermiculite supported layered double hydroxides with three-dimensional hierarchical structure

Abstract

Vermiculite supported Mg-Al layered double hydroxide (LDH@VMT) with three-dimensional hierarchical structure was successfully synthesized and the removal performance of LDH@VMT in soil was investigated for heavy metals removal (Cu2+, Pb2+, Zn2+ and Ni2+). Kinetics studies of heavy metals removal were well described by intraparticle diffusion and pseudo-second-order model. Adsorption isotherm data of Cu2+ and Pb2+ yielded a better accordance of Freundlich model, however, data of Zn2+ and Ni2+ were fitted Langmuir model well. Moreover, the different mechanisms of heavy metals removal by precipitation (Cu2+, Pb2+) and isomorphous replacement (Zn2+, Ni2+) were investigated and proposed, respectively. The effect of coexistence cations and column leaching experiments for practical performance assessment were also examined. The excellent removal performance suggested a promising strategy in heavy metals contaminated soil.