Application of Biochar in Removal of Per- and Polyfluoroalkyl Substances from Aqueous Medium

Per- and polyfluoroalkyl substances (PFAS) represent a diverse class of synthetic compounds with widespread industrial applications, leading to their ubiquitous presence in environmental matrices. This chapter provides a comprehensive exploration of PFAS contamination, emphasizing the environmental and health risks associated with these persistent substances. PFAS, exemplified by perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), exhibit resistance to degradation due to robust C–F bonds, resulting in bioaccumulation and potential health hazards. Among various remediation techniques, adsorption using biochar stands out as a cost-effective and efficient method for PFAS removal. The detailed investigation of biochar adsorbents, operating conditions, and adsorption capabilities demonstrates the applicability of this technique. Further, useful insights into enhancing biochar-based remediation solutions by considering numerous parameters that influence the adsorption process, such as pH, initial PFAS concentration, and biochar concentration were included. The kinetic study of PFAS adsorption on biochar, employing both pseudo-first-order and pseudo-second-order models, contributes to a deeper understanding of the adsorption mechanisms. The multifaceted interactions involved, such as diffusion, hydrophobic effects, electrostatic interactions, ion exchange, and hydrogen bonding, shed light on the complex interplay between PFAS and biochar surfaces.