(379b) Adsorptive Removal of PFAS Using Fly Ash Modified with Chitosan and Iron Oxide

Poly- and perfluoroalkyl substances (PFAS) are a class of synthetic organofluorine compounds widely used since the 1940s in industrial and consumer products such as firefighting foams, non-stick cookware, food packaging, and stain-resistant coatings. Their widespread utility stems from their exceptional thermal and chemical stability, conferred by strong carbon-fluorine (C–F) bonds and their amphiphilic nature. However, these same characteristics also render PFAS highly persistent in the environment, leading to their accumulation in air, water, soil, and living organisms. Commonly referred to as "forever chemicals," PFAS are increasingly associated with adverse health effects, including endocrine disruption, metabolic interference, carcinogenesis, and reproductive toxicity. Of particular concern is perfluorooctanoic acid (PFOA), a well-known PFAS compound linked to kidney and thyroid dysfunction and suspected carcinogenicity. The resilience of PFAS against conventional water treatment methods has driven the search for effective, low-cost, and sustainable remediation technologies.

In response to this environmental challenge, this study presents the development of a novel composite adsorbent synthesized by integrating fly ash with chitosan (CS) and magnetite (Fe₃O₄) nanoparticles for efficient PFAS removal from water. Fly ash, an abundant industrial by-product, serves as a porous support matrix, while chitosan contributes reactive amino groups for electrostatic interaction with PFAS molecules. The incorporation of Fe₃O₄ nanoparticles enhances the mechanical stability of the composite and allows for easy magnetic separation post-treatment. Preliminary results show that the composite demonstrates significantly higher adsorption capacity for PFOA compared to its individual components. Ongoing kinetic and isotherm studies aim to further elucidate the adsorption mechanisms. This work highlights the potential of magnetically separable, fly ash-based composites as cost-effective and environmentally sustainable solutions for PFAS-contaminated water remediation.