Biochar Adsorption: A Green Approach to PFAS Contaminant Removal

The widespread use of PFAS in nonstick cookware, hydrophobic textiles, stain-resistant fabrics, cosmetics, and floor coverings has led to their persistent presence in wastewater streams, posing significant human health and ecological risks. Exposure to PFAS is linked to adverse reproductive outcomes and elevated blood pressure in pregnant individuals, and it negatively impacts aquatic ecosystems, particularly algal populations and microbial communities. This evaluation focuses on biochar's efficacy and cost-efficiency in removing PFAS from water, highlighting its potential as a sustainable remediation method. Biochar's high microporous volumes (0.1–1.0 cm³/g), aromaticity, and surface oxygen-containing functional groups make it effective for PFAS adsorption. Various biochar production methods, such as pyrolysis of biomass waste, and innovative modification techniques like acid treatment, ball milling, and metal nanoparticle incorporation are explored to enhance PFAS adsorption capacity. The mechanisms, kinetics, and thermodynamics of PFAS adsorption onto biochar are examined, providing insights into molecular-level interactions and adsorption isotherms. Furthermore, machine learning models are utilized to understand the impact of processing parameters on PFAS removal efficiency. The review also presents toxicological studies on the harmful effects of PFAS exposure on organisms and humans, emphasizing the urgent need for effective remediation strategies. Ultimately, the potential of biochar-based approaches in treating PFAS-contaminated water is underscored by optimizing its physicochemical properties through innovative production and modification methods, along with predictive modeling of adsorption behavior.