Functionalized Biochar for In-situ Immobilization and Remediation of Cadmium-contaminated Soil: A Review

Cadmium (Cd (II)) contamination in agricultural soils is a global concern, posing threats to crops, ecosystems, and human health. Functionalized biochar (FCB), a sustainable and environmentally friendly soil amendment, has demonstrated significant potential for immobilizing and remediating Cd-contaminated agricultural soils. The application of FCB in heavy metal remediation has expanded rapidly. However, there is still a lack of comprehensive exposition focusing specifically on the application potential and prospects of FCB for remediating Cd-contaminated agricultural soils. This review aims to critically summarize the impact of Cd on soil ecology and the mechanisms by which FCB facilitates remediation in Cd-contaminated soils. It systematically examines the current status of Cd contamination in agricultural soils and the toxic effects of Cd (II) on plants. Additionally, the review explores various modification methods for FCB and highlights the latest advancements in the remediation of Cd-contaminated soils. It elucidates the primary mechanisms by which FCB immobilizes Cd (II) and analyzes the in-situ immobilization processes in contaminated soils. Furthermore, this paper predicts potential ecological risks. These risks are associated with the long-term application of FCB in heavy metal-contaminated soil remediation, critically evaluating its effectiveness in repairing Cd-contaminated soils. In summary, this work provides valuable insights into FCB for Cd-contaminated soil remediation, offering multifunctional improvement and remediation effects. However, further assessment of its environmental and economic feasibility is necessary to ensure its development as a cleaner and more sustainable solution.