Biochar-Based Treatment Technologies for PFAS Removal from Industrial Storamwater and Wastewater: Mechanisms, Field Applications, and Future Regulatory Implications

Abstract

Per- and polyfluoroalkyl substances (PFAS) represent a critical emerging contaminant class due to their extreme persistence, bioaccumulation potential, and documented adverse health effects in humans and wildlife. Biochar, a pyrolytic carbonaceous material derived from renewable biomass, has emerged as a promising sustainable and cost-effective adsorbent for PFAS removal from industrial stormwater and wastewater. This review synthesizes current knowledge on biochar-based treatment technologies for PFAS remediation, encompassing adsorption mechanisms, surface modification strategies, field-scale applications, and regulatory frameworks. Biochar's high microporous volumes (0.1–1.0 cm³/g), aromaticity, and surface oxygen-containing functional groups make it effective for PFAS adsorption. (Chavan et al., 2024) The adsorption mechanism is composed mainly of electrostatic interaction between positively charged biochar and deprotonated PFAS, hydrogen bonding between anionic species of PFAS and functional groups, and hydrophobic interaction between long-chain hydrophobic PFAS and biochar, with electrostatic interaction playing a major role in acidic media. (Zhang et al., 2023) Despite biochar's advantages, challenges remain in achieving complete defluorination, managing short-chain PFAS, optimizing regeneration, and scaling field applications. This review identifies key research gaps, technological barriers, and opportunities for integrating biochar technologies into comprehensive treatment trains to address the growing regulatory pressures and environmental risks posed by PFAS contamination globally.