Selective PFAS Removal and Regeneration Performance of a Polymer Functionalized Zeolite Nano Resin Evaluated by LC Tandem Mass Spectrometry

Per- and polyfluoroalkyl substances (PFAS) are persistent and analytically challenging contaminants that require both effective removal materials and reliable quantification at environmentally relevant concentrations. In this study, a polymer functionalized zeolite nano resin is evaluated for selective PFAS removal from water, with adsorption performance assessed using liquid chromatography-tandem mass spectrometry. The nano resin integrates the ion-exchange capacity and porosity of zeolite frameworks with tailored polymeric functional groups to enhance affinity toward anionic PFAS species.

Batch adsorption experiments demonstrate high adsorption capacities for both short- and long-chain PFAS. PFHxS and PFNA exhibit adsorption capacities of approximately 95–100 ng PFAS/g resin during initial use, while PFBS shows comparatively lower uptake, decreasing from ~98 ng/g in the first cycle to ~75 ng/g after reuse, indicating chain-length dependent selectivity. In mixed PFAS systems, adsorption follows the trend PFOS > PFOA > PFHxS > PFBS, with negligible uptake of PFNA (<1 ng/g), highlighting molecular size and hydrophobicity effects. Reusability studies reveal stable adsorption performance over five regeneration cycles. PFOS maintains adsorption capacities above 85 ng/g across all cycles, while PFOA remains in the range of 75–85 ng/g. Average adsorption rates of approximately 0.7 ng/g per cycle for PFOS and 2.7 ng/g for PFOA confirm sustained removal efficiency.

Desorption studies indicate efficient regeneration, with recovery of 95–100% of adsorbed PFOS and 70–80% of adsorbed PFOA. Overall, this work highlights the effectiveness of a polymer functionalized zeolite nano resin for selective PFAS removal and underscores the critical role of tandem mass spectrometry in analytically validating advanced water treatment materials.