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.

摘要

合成了坡缕石（PAL）涂层的纳米零价铁（nZVI），并用于修复被重金属污染的土壤。X射线衍射（XRD）和扫描电子显微镜（SEM）表明，大量的纳米级颗粒（粒径约为40-60 nm）均匀地分布在PAL的表面或孔上。氯化钙₂进行了萃取和TCLP试验，以评估PAL-nZVI改良的土壤中四种金属的生物利用度和迁移率。PAL和nZVI之间的质量比为2：1，表明在重金属稳定化过程中具有最佳效果。BCR连续萃取用于测量土壤中金属含量的变化。残留部分的浓度显着增加，表明在用PAL-nZVI修正后，重金属的部分趋于稳定。盆栽试验的结果表明，玉米的生物量增加，重金属的吸收显着降低，这表明PAL-nZVI可以通过增加土壤中重金属的稳定性来刺激玉米的生长。因此，