Removal of per- and polyfluoroalkyl substances by graphene oxide-based nanoadsorbents: A review

Due to their great persistence, toxicity, and ubiquitous presence in water systems, per- and polyfluoroalkyl substances (PFASs) that present significant environmental and public health issues. The use of graphene oxide (GO)-based nanoadsorbents for the removal of PFASs is critically assessed in this review. For efficient PFAS adsorption, GO's large surface area, adjustable surface chemistry, and modifiability allow for a number of interactions, such as hydrophobic forces, hydrogen bonds, and electrostatic attraction. Under optimal circumstances, functionalized GO-based nanoadsorbents showed outstanding removal efficiencies (>99 %), with adsorption capacities sometimes surpassing 700 mg/g. Adsorption efficacy is significantly impacted by environmental factors such temperature, ionic strength, pH, and the presence of natural organic matter. Due to decreased electrostatic interactions, GO-based nanoadsorbents were negatively impacted by divalent cations and competing anions and functioned best at acidic to neutral pH. More than 85 % of the adsorbent's capacity was recovered through regeneration using alcohol-based solvents (such as ethanol or isopropyl alcohol), confirming its useful reusability. There are still important research gaps in spite of these developments. Most adsorption research has been carried out in simplified lab settings without validation in real-world matrices like industrial or municipal effluent. In order to clarify PFAS–adsorbent interactions across a variety of PFAS species, atomic-scale modeling (such as density functional theory and molecular dynamics) is required.