Technologies for removing heavy metal from contaminated soils on farmland: A review

With the rapid development of industrialization and agricultural intensification and scale, the problem of heavy metal pollution in farmland has attracted widespread attention. There exist various methods to remediate heavy metal contaminated soils, but the sources and extent of contamination in agricultural soils are more complex and require higher selection of remediation technologies. This paper discusses in detail the status of heavy metal pollution in agricultural fields and the research progress of removal technologies and provides an in-depth analysis and comparison of remediation technologies from three aspects: physicochemical, electrochemical, and biological, which provides references and directions for the selection of future remediation technologies in agricultural fields. It was found that the existing morphology of soil heavy metals is an important reference for the selection of soil remediation methods; in practical applications, both phytoremediation and removal of heavy metals from agricultural soils using magnetic biochar have good potential for development. Phytoremediation of farmland through crop rotation or intercropping can not only achieve remediation while producing, but also optimize the soil environment. However, phytoremediation requires a high degree of pollution in the soil environment, the selection of plant species is a key step in phytoremediation and improving the tolerance of plants to heavy metals requires in-depth research. Magnetic biochar is an ideal material for soil remediation because of its relatively short remediation time and reusable materials and metals. However, the binding mechanism between magnetic biochar and heavy metals, the effect of magnetic biochar on soil microorganisms to be further studied.