Design of Bio-Based Adsorbents for Removal of PFAS and Emerging Contaminants from Wastewater

Abstract

This study critically examines the design, performance, and sustainability of bio-based adsorbents for the removal of per- and polyfluoroalkyl substances (PFAS) and other emerging contaminants (ECs) from wastewater systems. Given the persistence, mobility, and bioaccumulative nature of PFAS, conventional treatment technologies such as activated carbon and advanced oxidation processes often exhibit limited efficiency, particularly for short-chain compounds. This review synthesizes recent advancements (2019–2025) in bio-based adsorbent materials, including agricultural residues, biochar, lignin-derived carbons, and engineered biopolymers, with emphasis on their physicochemical properties and adsorption performance. Mechanistic insights reveal that adsorption is governed by a combination of hydrophobic interactions, electrostatic attraction, pore filling, and surface complexation, with performance strongly influenced by adsorbent surface functionality and water matrix conditions. Comparative analysis indicates that modified bio-based adsorbents can achieve removal efficiencies exceeding 90% for long-chain PFAS under optimized conditions, although performance variability persists for short-chain analogues. Sustainability assessment highlights significant advantages, including reduced lifecycle environmental impact, lower material costs, and alignment with circular economy principles through biomass valorization. However, challenges related to regeneration efficiency, selectivity, and scalability remain critical barriers to full-scale deployment. The study identifies key research gaps and proposes future directions involving hybrid treatment systems, advanced functionalization strategies, and data-driven material optimization. These findings position bio-based adsorbents as viable candidates for next-generation sustainable wastewater treatment technologies.