Characteristics of biochar and its role in the remediation of heavy metals in soil

Abstract

With the increasing threat of soil heavy metal pollution to the quality of agricultural products and human health, biochar has been widely studied as a substance that can effectively adsorb heavy metals. This study reviewed the preparation of biochar as well as its types and properties and discussed the role and potential risks of biochar in the remediation of heavy metals in soil. Heavy metal pollution in the soil mainly comes from industrial pollution discharge, good drainage, the usage of chemical fertilizers, pesticides and other illegal applications, and it has great influence on plants, human health and soil environment. Biochar can not only adsorb heavy metals in the soil effectively, but also keep the soil fertile and improve crop yields. In addition, different properties of biochar are controlled by different raw materials and production conditions, such as pH, specific surface area and cation exchange capacity. These properties also determine their different interaction mechanisms. The direct effects mainly include complexation, reduction, ion exchange, electrostatic attraction and precipitation, while the brief effects affect the mobility and bioavailability of heavy metals in soil. The risk of biochar application that provides the basis for the production and utilization of biochar in the future was also discussed in the end.