Progress on the removal of PFAS contamination in water by different forms of iron-modified biochar

Per- and polyfluoroalkyl substances (PFAS) contamination poses a significant threat to human health. Iron-modified biochar is an eco-friendly, cost-effective, and efficient adsorption material. There is a beneficial interaction between iron groups and biochar to remove PFAS from water through adsorption and degradation. The removal mechanism of the iron-modified biochar mainly includes advanced oxidation, iron group reduction, and adsorption. The adsorption mechanism shifted from being dominated by hydrophobic interactions to electrostatic interactions and ion exchange. Different forms of iron-modified biochar showed excellent removal of short-chain PFAS, which is not found in other modified biochar. Few existing studies have systematically investigated the role of various forms of iron-modified biochar in PFAS removal. Accordingly, this review explores the following areas, the synthesis methods of different forms of iron-modified biochar, the removal effect on long and short-chain PFAS, the key factors affecting removal capacity and the mechanisms of their interaction, the mechanism of PFAS removal, and the regeneration capacity of the composites. In this study, the potential of different forms of iron-modified biochar for PFAS remediation was explored in depth. To provide new ideas for subsequent studies of PFAS removal using iron-modified biochar.