Efficient PFAS Removal by Amine-Functionalized Sorbents: Critical Review of the Current Literature

Abstract

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of persistent and mobile fluoro-organic chemicals that have been detected in many water supplies, and their recommended safe concentrations in drinking water are as low as 6 ng/L. Current technological advances suggest that amine-containing sorbents can provide alternative solutions to PFAS control in the treatment of municipal water and wastewater at relatively low PFAS concentrations. The objective of this review is to provide critical analysis of the development and application of amine-containing sorbents for PFAS removal. The removal of PFAS by aminated sorbents relies on the combined effects of three main factors: (i) electrostatic interactions with functional groups of the sorbent, (ii) hydrophobic interactions with the sorbent and between PFAS molecules, and (iii) sorbent morphology. The design of next-generation sorbents should take into consideration these three factors and their relative contribution. We also provide an outlook and highlight of the key areas of innovative research needs to develop more efficient sorbents that will enable compliance with the increasingly stringent regulations of PFAS.

Rapid and Efficient Removal of Perfluorooctanoic Acid from Water with Fluorine-Rich Calixarene-Based Porous Polymers

“…Further molecular-level characterization of the polymers was achieved by solid state NMR spectroscopy. Solid-state cross-polarization magic angle spinning (CP/MAS) 13 C NMR spectra (Figure 1b) exhibited resonances in the range of 105 -145 ppm, which correspond to the aromatic carbons of the calixarene macrocycle and the fluorinated linkers. 19 F solid-state NMR spectra of FCX4-P and FCX4-BP; (d) N2 adsorption and desorption isotherms for FCX4-P, FCX4-BP and the corresponding non-fluorinated polymers, CX4-P and CX4-BP.…”

“…In addition, adsorbents have reasonable rates of removal, low costs, high surface-area-to-volume ratios, and an abundance of adsorption sites. 13 The most commonly used adsorbent for PFOA removal is activated carbon (AC). Despite being affordable and relatively efficient at removing PFOAs, ACs suffer from low affinity for PFOA at environmentally relevant concentrations, 14 and their regeneration is energy-intensive.…”

Amyloid fibril-based membranes for PFAS removal from water

“…This phenomenon is in good agreement with the other related reports [29][30][31] . Long-chain PFASs with a larger number of C-F units are more hydrophobic than the short-chain ones, leading to higher hydrophobic interaction by amyloid fibrils [32][33][34] . Meanwhile, the short-chain PFASs are more soluble, and the effect of hydrophobicity decreases significantly.…”

Screening of organic micropollutants in raw and drinking water in the Yangtze River Delta, China

“…Negative removal efficiency may be explained by time-dependent concentrations and the lag time between sampling raw and finished water, degradation of PFAS precursors to persistent PFASs [37] and desorption/breakthrough of PFASs from granular activated carbon (GAC) or other filter types within the DWTP [38]. GAC and anion exchange filters are currently used for removal of PFASs in DWTPs; however, development of new treatment options are needed, in particular for the shorter chain PFASs [38][39][40].…”