Stabilisation of heavy metals in soil using nanoscale zero-valent iron coated with palygorskite

ABSTRACT

The nanoscale zero-valent iron (nZVI) coated with palygorskite (PAL) was synthesised and used to remediate the soil contaminated by heavy metals. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that a large number of nanoscale particles (had a grain size of 40–60 nm approximately) were distributed on the surface or pores of PAL homogeneously. The CaCl₂ extraction and TCLP test were carried out to evaluate the bioavailability and mobility of four metals in soil amended by PAL-nZVI. The loading mass ratio of 2:1 between PAL and nZVI showed the optimised effect during the heavy metals’ stabilisation. BCR sequential extraction was employed to measure the change of metal fractions in soil. The residual fraction concentration increased significantly, indicating that the fraction of heavy metals tended to stabilise after amended with PAL-nZVI. The result of pot experience showed that the corn’s biomass increased, and the uptake of heavy metals was reduced significantly, which suggested the PAL-nZVI could stimulate the growth of corn by increasing the stabilisation of heavy metals in soil. Thus, PAL-nZVI as a novel and high-efficiency amendment could be applied to remediate the heavy metals-contaminated soil.

KEYWORDS:

• PAL-nZVI
• immobilisation
• bioavailability
• heavy metals
• accumulation
• contaminated soil

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The current research was supported by the National Natural Science Foundation of China (No. 51668034)

Notes on contributors

Xuan Mi

Xuan Mi is a Ph.D. candidate of Lanzhou Jiaotong University major in the environmental science and engineering. Her research examines to synthetic the high efficiency, environment friendly and low cost remediate material for the stabilization of heavy metals in the soil. Her research aims to provide a theoretical basis and practical guide for in situ field-scale remediations of heavy metals in the soil.

Jun Ren

Jun Ren is a Professor at Lanzhou Jiaotong University in the school of Environmental and Municipal Engineering, doctoral tutor of environmental science and engineering. He has been engaged in research and teaching in the fields of environmental science and engineering and environmental ecology. His research devotes to the remediation of heavy metal pollution in the soil and carried out technical deepening and technical innovation in multi-layer. His research aims to provide a theoretical basis and practical guide for large-scale engineering restoration of heavy metals contaminated soil.

Ling Tao

Ling Tao is a Professor at Lanzhou Jiaotong University in the school of Environmental and Municipal Engineering, master tutor of environmental ecology. She has been engaged in the research and teaching of environmental science, plant ecology, environmental ecology and other fields. Her research examines the remediation of heavy metal pollution in the soil using ecological remediation technology.