β-Cyclodextrin Polymer Network Sequesters Perfluorooctanoic Acid at Environmentally Relevant Concentrations

Abstract

Per- and poly fluorinated alkyl substances (PFASs), notably perfluorooctanoic acid (PFOA), contaminate many ground and surface waters and are environmentally persistent. The performance limitations of existing remediation methods motivate efforts to develop effective adsorbents. Here we report a β-cyclodextrin (β-CD)-based polymer network with higher affinity for PFOA compared to powdered activated carbon, along with comparable capacity and kinetics. The β-CD polymer reduces PFOA concentrations from 1 μg L to <10 ng L, at least 7 times lower than the 2016 U.S. EPA advisory level (70 ng L), and was regenerated and reused multiple times by washing with MeOH. The performance of the polymer is unaffected by humic acid, a component of natural organic matter that fouls activated carbons. These results are promising for treating PFOA-contaminated water and demonstrate the versatility of β-CD-based adsorbents.

A review of emerging technologies for remediation of PFASs

“…For PFASs, there are no known biodegradation mechanisms, so the emplaced particulate‐activated carbon will saturate with these contaminants. In the same manner that GAC is less effective at removing shorter chain PFAAs and PFAA precursors from water (Xiao, Ulrich, et al., ), the injected particulate‐activated carbon is also expected to be less effective at removing these PFASs. Once the activated carbon has saturated with PFASs, it could form a secondary source zone, subsequently releasing PFASs.…”

“…There are currently no published studies on the effectiveness of GAC in removing cationic, zwitterionic, and anionic precursor compounds; however, a recent theoretical study suggests some precursors are unlikely to be effectively removed by GAC (Xiao, Ulrich. et al., ).…”

Theoretical and experimental studies on the separation of cinnamyl acetate and cinnamaldehyde by adsorption onto a β-cyclodextrin polyurethane polymer

“…15,16 b-Cyclodextrin (b-CD) polymers, prepared by crosslinking b-CD or its derivatives with functional groups have been studied widely as adsorbents for chromatographic separation and water treatment applications. [17][18][19][20] The most notable feature of b-CD polymers is the ability to selectively encapsulate a wide range of molecules due to the preservation of the hydrophobic hollow cavity that belongs to the b-CD molecule in their skeletons.…”

Three‐Dimensional Anionic Cyclodextrin‐Based Covalent Organic Frameworks

“…[1] These intriguing advantages render COFs ideal candidates for applications in gas storage and separation, [2] optoelectronics, [3] catalysis, [4] and energy storage, [5] forexample.W hen classified according to their structural dimensions, COFs can be divided into two-dimensional (2D) and threedimensional (3D) frameworks.I n2 DC OFs,t he building blocks are periodically and covalently restrained in 2D polymeric layers,w hich can further stack to form eclipsed or staggered structures through non-covalent interactions. [10] Nonetheless,o wing to the kinetically controlled nature of the co-condensation reaction, CD-based porous polymers linked via covalent bonds are usually amorphous.Stoddart and co-workers pioneered the preparation of aseries of crystalline CD-based metal-organic frameworks (CD-MOFs) by linking g-CD through alkali metal ion coordination. In all of the known 3D COFs, [4c, 7] the tetrahedral linkages are based on either sp 3 -hybrized carbon or silane elements.T he development of 3D COFs that are based on soft and flexible building units,such as cyclodextrins (CDs), which may impart the COFs with dynamic and resilient characteristics,ishighly desired, yet largely unmet.…”

“…[8] These hydroxy groups can serve as chelating and nucleophilic sites and provide the opportunity to link CD into 3D polymeric networks. [10] Nonetheless,o wing to the kinetically controlled nature of the co-condensation reaction, CD-based porous polymers linked via covalent bonds are usually amorphous.Stoddart and co-workers pioneered the preparation of aseries of crystalline CD-based metal-organic frameworks (CD-MOFs) by linking g-CD through alkali metal ion coordination. [10] Nonetheless,o wing to the kinetically controlled nature of the co-condensation reaction, CD-based porous polymers linked via covalent bonds are usually amorphous.Stoddart and co-workers pioneered the preparation of aseries of crystalline CD-based metal-organic frameworks (CD-MOFs) by linking g-CD through alkali metal ion coordination.…”