Highly effective stabilization of Cd and Cu in two different soils and improvement of soil properties by multiple-modified biochar

Heavy metal contamination in soil has attracted great attention worldwide. In situ stabilization has been considered an effective way to remediate soils contaminated by heavy metals. In the present research, a multiple -modified biochar (BCM) was prepared to stabilize Cd and Cu contamination in two different soils: a farmland soil (JYS) and a vegetable soil (ZZS). The results showed that BCM was a porous-like flake material and that modification increased its specific surface area and surface functional groups. The incubation experiment indicated that BCM decreased diethylenetriaminepentaacetic (DTPA)-extractable Cd and Cu by 92.02% and 100.00% for JYS and 90.27% and 100.00% for ZZS, respectively. The toxicity characteristic leaching procedure (TCLP)-extractable Cd and Cu decreased 66.46% and 100.00% for JYS and 46.33% and 100.00% for ZZS, respectively. BCM also reduced the mobility of Cd and Cu in soil and transformed them to more stable fractions. In addition, the application of BCM significantly increased the soil dehydrogenase, organic matter content and available K (p < 0.05). These results indicate that BCM has great potential in the remediation of Cdand Cu-contaminated soil.

Automated summary

The study found that multi-modified biochar (BCM) has great potential in stabilizing Cd and Cu contamination in soil, effectively reducing the extractability of heavy metals, reducing the leaching of toxic characteristics, and increasing the organic matter and available potassium content in soil.