Magnetic amino-functionalized graphene oxide nanocomposite for PFAS removal from water

Abstract

The “forever chemicals”, per- and polyfluoroalkyl substances (PFAS), have become a threat to public health and environment because of their toxicity and bioaccumulation. Addressing this critical issue, we develop a state-of-the-art nanocomposite adsorbent by covalently grafting amine functional groups onto graphene oxide (GO) surfaces and making them magnetic with iron-oxide (Fe₃O₄) nanoparticles. This process results in the creation of magnetic amine-functionalized graphene oxide (MAGO). The efficiency of MAGO is evaluated in the adsorptive removal of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorobutane sulfonate (PFBS) as model long-chain and short-chain PFAS under different experimental conditions. Our findings reveal that MAGO achieves remarkable removal rates—exceeding 95% for long-chain PFAS and 85% for short-chain PFAS within just 30 minutes—demonstrating not only rapid kinetics but also a resilience across pH levels from 4 to 7. These results are indicative of the synergistic effects of GO and amine groups, harnessing both electrostatic and hydrophobic interactions to adsorb PFAS molecules. MAGO not only shows potent pollutant removal but also has impressive regeneration capabilities. Moreover, we demonstrate a novel liquid phase extraction method for PFAS detection, utilizing a colored methylene blue-PFAS complex for spectrophotometric analysis.