Recent advances in activated carbon driven PFAS removal: structure-adsorption relationship and new adsorption mechanisms

Abstract

Highly persistent per- and polyfluorinated alkyl substances (PFAS) have been extensively used worldwide for decades and are now ubiquitous in the ecosystem. To combat problems related to PFAS accumulation in the environment and their intrusion into the human body, PFAS adsorption and subsequent breakdown of carbon and fluorine chains are under intense research. Activated carbon (AC) is a widely used adsorbent for PFAS removal from water or wastewater. However, some of its shortcomings include inefficiency in short-chain PFAS removal, a lack of selectivity, overall low adsorption performance, and concerns regarding economic sustainability. Herein, we reviewed the recent innovative carbon-based technologies that aim to address these challenges. In particular, we focus on AC’s topography engineering, defunctionalization (e.g., removing surface functional groups), hydrophobicity or surface charge modification, water-confining nanopores, and AC-nanobubbles synergy. The underlying mechanisms of these novel approaches and their effectiveness in PFAS adsorption are discussed, along with their advancements and limitations. Additionally, the PFAS adsorption and regeneration ability of high-performance ACs are presented and compared. Finally, we address current challenges and offer perspectives on advancing this technology.