Adsorption as a remediation technology for short-chain per- and polyfluoroalkyl substances (PFAS) from water – a critical review

Abstract

Because of their ubiquitous presence in the environment and their potential toxicity to human health, per- and polyfluoroalkyl substances (PFAS) have drawn great attention over the past few years. Current...

Adsorption mechanisms of short-chain and ultrashort-chain PFAS on anion exchange resins and activated carbon

“…Recent literature encourages the use of treatment-train approaches for the sequential removal of different classes of PFAS: the first step focuses on the efficient elimination of hydrophobic long-chain PFAS, while the subsequent steps can target shorter-chain PFAS through anion exchange. 18 However, the current occurrence trends suggest that shortchain PFAS will be far more abundant in the environment than long-chain PFAS in the future. 6,11 Our results indicate that the effect of competition among short-chain PFAS with different chain lengths, molecular sizes, and functional groups can significantly affect their adsorption, leading to their incomplete adsorption.…”

“…The presence of inorganic ions as electrolytes can also cause the electrical double-layer compression of A900, thereby reducing the net positive charge (charge screening) on the resin surface. 18 As a result, A900 can be rendered less favourable for P 3 adsorption in the presence of CaCl 2 . Charge screening on the adsorbent surface by inorganic Cl − is also possible, 42 which might affect its interaction with the P 3 anions.…”

“…Nevertheless, these techniques are energy-intensive and require extensive infrastructure/costs for large-scale applications. 18 Amongst all the different techniques utilized for PFAS removal, adsorption has remained one of the most widely employed methods 19 owing to its simple operation, costeffectiveness, and high removal efficiencies. 6 Most adsorption studies to date have focused on long-chain PFOA and PFOS, 20 whereas data on the adsorption of short-chain PFAS, especially ultrashort-chain PFAAs, remain limited.…”

“…Nevertheless, these techniques are energy-intensive and require extensive infrastructure/costs for large-scale applications. 18…”

“…6 Most adsorption studies to date have focused on long-chain PFOA and PFOS, 20 whereas data on the adsorption of short-chain PFAS, especially ultrashort-chain PFAAs, remain limited. 6 Moreover, adsorption mechanisms of short-chain PFAS have been mostly investigated in the presence of longer-chain counterparts, 18 which may lead to erroneous conclusions due to competition and interference effects from long-chain PFAS. Activated carbon (AC) and anion exchange resins (AERs) are the two most explored adsorbents for the removal of short-chain PFAS.…”