Emerging two-dimensional materials in PFAS remediation: a comprehensive review of adsorption mechanisms and efficiency

Abstract

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are extensively applied in both industrial and consumer products. To overcome the drawbacks of traditional treatment techniques, researchers are increasingly exploring two-dimensional (2D) materials as innovative solutions for PFAS remediation. Due to their distinctive properties, 2D materials exhibit significant potential for environmental remediation applications. This review examines a range of 2D materials, including graphene, MXenes, 2D metal-organic frameworks (MOFs), covalent organic frameworks (COFs), layered double hydroxides (LDHs), phosphorene, and hexagonal boron nitride (h-BN). It highlights their efficacy in adsorbing PFAS from water. By exploring the results of performance from available literature, it can be stated that graphene has been among the best-performing materials for a number of reasons. These reasons include its extensive surface area and the ability to alter its surface chemistry to capture PFAS via adsorption. Due to their structural and electrochemical stability, as well as the capacity to remove PFAS from waters of different matrices/conditions, MXenes (although with a limited number of reports) were the second-best-performing material. In addition, among the 2D MOFs and COFs, the ability to adsorb PFAS efficiently was attributed to their engineered porous frameworks. LDHs also have an effective surface for capturing PFAS in the waters because their positively charged metal hydroxide layers and PFAS are negatively charged. h-BN, which possesses a graphene-like layered architecture and provides remarkable chemical and thermal stability. Phosphorene, although less studied, exhibits a highly reactive surface owing to its high electron density, suggesting significant potential for adsorption applications.