Biochar as a potential soil remediation agent for heavy metals in agriculture

Biochar is one of the most concerned research hotspots at present, which is a stable and carbon-rich solid produced by pyrolysis of organic biomass under anoxic conditions. Biochar has abundant pore structure, functional groups, aromatic hydrocarbons and other characteristics, which enable it to improve soil physical and chemical properties, increase nutrient content, and regulate soil microbial community structure. In recent years, with the continuous research on biochar, the role of biochar in the remediation of heavy metal pollution has been further studied. The physical adsorption, ion exchange, electrostatic attraction, complexation reaction, mineral precipitation, redox and other functions of biochar are the main factors for repairing heavy metal ions. In addition, immobilization is the primary goal of biochar remediation of heavy metals in agricultural soils, because it can greatly reduce the risk of human health caused by heavy metals entering the food chain. This paper reviewed the current knowledge of biochar and its function in agricultural heavy metal soil. Based on the background of heavy metal pollution in agricultural soil in China, the possible remediation mechanism of biochar was discussed. It provides scientific basis for the development and application of biochar in the remediation of heavy metal pollution in agricultural soil in China.