Synergistic Approaches in PFAS Remediation: Outlook for Sustainable In Situ Mitigation by Combined Adsorption and Photocatalysis

Abstract Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants with widespread environmental occurrence. Their toxicity and resistance to degradation pose serious risks to ecosystems and human health. While existing separation (e.g., adsorption, filtration) and degradation (e.g., photochemical, electrochemical, thermal) technologies can achieve partial PFAS removal, limitations such as high energy demand, poor cost-efficiency, and harsh operating conditions hinder their in situ application. In this context, a synergistic approach, a system in which adsorption and degradation are functionally coupled rather than applied as independent sequential unit operations, has emerged as a promising route. This review critically examines the coupling of biopolymer-based adsorption and photocatalytic degradation as a sustainable and effective solution for PFAS remediation. Biopolymers such as lignin, chitosan, and cellulose offer a renewable alternative to conventional sorbents, exhibiting adsorption capacities of ∼50–500 mg g–1 and beyond in advanced systems and removal efficiencies of up to 99% in dilute conditions, while photocatalytic platforms, such as semiconductor-based systems, reach ∼32–100% degradation efficiencies, with up to 92% defluorination in optimized systems. When combined functionally, these systems enhance PFAS degradation through interfacial preconcentration and reduce secondary waste. The review critically evaluates recent advances in material development, mechanistic understanding, and system integration, alongside the roles of Life Cycle Assessment and Artificial Intelligence/Machine Learning, as complementary tools guiding the design and deployment of sustainable PFAS-remediation strategies.