REGENERATION OF STYDEX POLYMERS USED FOR PFAS REMEDIATION AND INVESTIGATIONS OF SIMULTANEOUS PFAS DESTRUCTION
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Per- and polyfluoroalkyl substances (PFASs) are a large class of synthetic chemicals, encompassing over 4,000 compounds, that have been widely used in industrial and consumer products. Among them, perfluoroalkyl acids (PFAAs)—particularly perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs)—have garnered the most scientificattention due to their environmental persistence, bioaccumulative potential, and adverse effects on human and ecological health. The remediation of PFAAs remains difficult due to their trace-level presence and high resistance to thermal and chemical degradation. As such, adsorption remains the most practical and widely implemented strategy for their removal in drinking water, wastewater, and remediation systems. Conventional adsorbents such as granular activated carbon (GAC) and anion-exchange resins (AERs) have been used for PFAA removal but are often limited by low selectivity, high replacement costs, and inhibition from water matrix constituents. Next-generation cyclodextrin polymers (CDPs), including styrenic CDPs known as StyDex, offer more selective and efficient adsorption performance. This thesis investigates: (1) regeneration strategies to restore the performance of PFCA-loaded StyDex polymers; and (2) destruction methods to mineralize PFASs concentrated in the regeneration waste stream. Through systematic optimization, two high-performing regeneration solutions were identified—70% isopropanol (IPA) + 20 mM ammonium acetate (AA), and 90% dimethyl sulfoxide (DMSO) + 10% IPA + 20 mM AA, and 70% isopropanol (IPA) + 20 mM ammonium acetate (AA) is capable of achieving over 90% regeneration rate across multiple cycles. Importantly, the regeneration solution composed of 90% DMSO + 10% IPA was also found to facilitate efficient PFCA destruction through low-temperature thermal treatment. Nearly complete degradation of PFCAs was achieved within 96 hours at 90–100 °C, demonstrating that the same solution can serve as both an effective regenerant and a destruction medium. This dual-function approach provides a promising closed-loop pathway for PFAS remediation that integrates high-performance adsorption, sustainable regeneration, and efficient contaminant destruction.