Graphene-Based Adsorbents for the Removal of Per- and Polyfluoroalkyl Substances (PFAS) from Wastewater: A Review
Shaza Adel Hammoud
*
UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, Shanghai, China and Ministry of Local Administration and Environment, Damascus, Syria.
Sali Mustafa
UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, Shanghai, China.
Danial Ali
AL-Nahrain University, Bagdad, Iraq.
*Author to whom correspondence should be addressed.
Abstract
Per- and polyfluoroalkyl substances (PFAS) pose a significant global threat to water security because of their extreme persistence, mobility, and proven adverse health effects. Their strong carbon-fluorine (C–F) bonds provide high stability, resulting in widespread environmental contamination from industrial sources or indirectly through landfill leachates and wastewater discharges. The urgent need for effective cleanup has made adsorption a leading strategy, with carbon-based materials—especially graphene oxide (GO) and its derivatives—emerging as highly promising adsorbents. This review thoroughly examines the molecular-level adsorption mechanisms of PFAS on graphene-based nanomaterials, aiming to link material properties with removal efficiency.
By synthesizing evidence from experimental studies—including isotherm and kinetic analyses, FTIR, XPS, and XRD characterization—and computational molecular dynamics (MD) simulations, we clarify the main interactions responsible for PFAS sequestration. Our study confirms that adsorption is mainly driven by a combination of electrostatic attraction and hydrophobic interactions. Electrostatic forces, strengthened by amine functionalization (e.g., in MAGO nanocomposites), enable quick removal (>95% for PFOS in 30 minutes) and are essential for capturing short-chain PFAS. At the same time, hydrophobic interactions with the graphene basal planes favor long-chain compounds, with MD simulations showing adsorption energies as high as -171 kcal/mol for PFOS. Advanced materials like polyamine-coated GO (PAGO) exhibit record-breaking capacities (~3070 mg/g for PFOS), while β-cyclodextrin-modified GO targets short-chain PFAS with 65% removal of PFBA within 15 minutes, surpassing traditional activated carbon.
We conclude that strategically functionalizing GO to enhance its surface charge and hydrophobicity is essential for achieving high-efficiency, broad-spectrum PFAS adsorption. This mechanistic insight offers a vital basis for designing next-generation water treatment technologies capable of tackling the persistent issue of PFAS contamination.
Keywords: Graphene oxide, PFAS, adsorption, perfluoroalkyl and polyfluoroalkyl substances