Biochar for sustainable immobilization of potentially toxic elements in contaminated farmland

Biochar has variegated uses for sustainable immobilization of potentially toxic elements (PTEs) in contaminated farmland, which is described in this chapter. The effects of biochar on the mobility and phytoavailability of cationic PTEs (e.g., Al, Mn, Cd, Pb, Hg, Zn, Cu, Ni) and anionic PTEs (e.g., Cr, As, Se, Sb) in farmland soils and the main mechanisms relevant for this purpose are summarized. Moreover, the limitations and challenges of employing biochar for the remediation of PTEs-contaminated farmland soils are discussed. The directions for further study in this emerging frontier of biochar-related research are also proposed to facilitate the large-scale application of biochar. This review can offer important references to the development of biochar technologies for the remediation of and their safe application to PTEs-contaminated farmlands.