Rapid Immobilization of Transferable Ni in Soil by Fe78Si9B13 Amorphous Zero-Valent Iron

Fe-Si-B amorphous zero-valent iron has attracted wide attention because of its efficient remediation of heavy metals and dye wastewater. In this paper, the remediation effect of amorphous zero-valent iron powder (Fe78Si9B13AP) on Ni contaminated soil was investigated. Results show that the immobilization efficiency of nickel in soil by Fe78Si9B13AP with low iron content is higher than that by ZVI. The apparent activation energies of the reactions of Fe78Si9B13AP with Ni2+ ions is 25.31 kJ/mol. After continuing the reaction for 7 days, Ni2+ ions is mainly transformed into monoplasmatic nickel (Ni0) and nickel combined with iron (hydroxide) oxides. Microstructure investigations show that the product layer with nano-pore structure is beneficial to improve the reaction activity of Fe78Si9B13AP. After that, a magnetic separation process is introduced, in which part of the immobilized Ni are removed to reduce the total Ni content in soil by 58.21%. The results of simulated acid rain leaching experiment showed that the release of Ni in the soil after Fe78Si9B13AP remediation is 62.89% lower than that before remediation.