Study on the Effect of Biochar, Bentonite and Lignite on the Remediation of Heavy Metal Contaminated Soil

The in-situ repair of heavy metals in contaminated soil is to change the status of the presence of heavy metals in soil by applying some active passivation repair materials to the soil, and by dissolving precipitation, ion exchange adsorption, redox, organic convergence and other reactions, reducing the effective concentration, migration and biological effectiveness of heavy metals in the soil. This method is low-cost, simple to operate, fast-acting and suitable for large-scale promotion, and plays an irreplaceable role in the restoration of heavy metal contaminated soil. This paper summarizes the effect of passivation repair of biochar, bentonite and lignite on heavy metal contaminated soil. This paper analyzes the current situation of research in this field and the main problems in this field, and in the future, we should focus on the potential environmental risk of passivation repair agent to soil-crop system and the long-term stability evaluation of the field effect of passivation material repair.