TY - JOUR
T1 - Cyclodextrin Polymers with Nitrogen-Containing Tripodal Crosslinkers for Efficient PFAS Adsorption
AU - Yang, Anna
AU - Ching, Casey
AU - Easler, Maeghan
AU - Helbling, Damian E.
AU - Dichtel, William R.
N1 - Funding Information:
This research was supported by the Strategic Environmental Research and Development Program (ER18-1026) and the Dreyfus Environmental Postdoc Fellowship (EP-16-087). This work made use of the IMSERC at Northwestern University, which has received support from the NSF (CHE-1048773), Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSFECCS-1542205), the State of Illinois, and International Institute for Nanotechnology (IIN).
PY - 2020/9/8
Y1 - 2020/9/8
N2 - Per- and polyfluoroalkyl substances (PFAS) are widely used industrial chemicals that are of a great concern because of their pervasive presence in water resources and association with negative health effects. Crosslinked β-cyclodextrin-containing (β-CD) polymer adsorbents have shown promising performances for sequestering PFAS. Recently, installing amino groups into the crosslinkers of a β-CD polymer network improved the binding of many anionic PFAS, including short-chain and branched derivatives. However, the relative importance of the electrostatic interactions from the amino groups and the host-guest interactions within the cavity of the β-CD for PFAS binding are unclear. Herein, β-CD-based adsorbents crosslinked with tripodal crosslinkers containing three amino or amido groups are prepared with comparable physicochemical properties to investigate the respective roles of the crosslinker and β-CD in binding affinity and capacity for anionic PFAS. β-CD polymers containing amines showed superior removal for ten anionic PFAS compared to polymers containing amido groups. Both β-CD polymers have superior performance for perfluorooctanoic acid (PFOA) removal compared to activated carbons (ACs), consistent with β-CD:PFOA inclusion complexes playing an important role. Adsorbents containing amido groups showed low binding affinity and capacity for GenX, whereas the amine-functionalized polymer had outstanding affinity and capacity for GenX (KL = 8.8 × 104 M-1, QM = 222 mg g-1), underscoring the essential role of electrostatic interactions for removing short-chain and branched PFAS. The amine-containing β-CD polymer exhibited 100-fold higher affinity and twice the capacity (KL = 1.8 × 106 M-1, QM = 457 mg g-1) for PFOA compared to GenX, which are the highest reported values for β-CD polymers. These results highlight the synergistic effects of electrostatic interactions and host-guest interactions in β-CD polymers as important design criteria for efficient removal of anionic PFAS from water. This study further demonstrates broad tunability of crosslinked β-CD polymers and their promise as adsorbents for PFAS remediation.
AB - Per- and polyfluoroalkyl substances (PFAS) are widely used industrial chemicals that are of a great concern because of their pervasive presence in water resources and association with negative health effects. Crosslinked β-cyclodextrin-containing (β-CD) polymer adsorbents have shown promising performances for sequestering PFAS. Recently, installing amino groups into the crosslinkers of a β-CD polymer network improved the binding of many anionic PFAS, including short-chain and branched derivatives. However, the relative importance of the electrostatic interactions from the amino groups and the host-guest interactions within the cavity of the β-CD for PFAS binding are unclear. Herein, β-CD-based adsorbents crosslinked with tripodal crosslinkers containing three amino or amido groups are prepared with comparable physicochemical properties to investigate the respective roles of the crosslinker and β-CD in binding affinity and capacity for anionic PFAS. β-CD polymers containing amines showed superior removal for ten anionic PFAS compared to polymers containing amido groups. Both β-CD polymers have superior performance for perfluorooctanoic acid (PFOA) removal compared to activated carbons (ACs), consistent with β-CD:PFOA inclusion complexes playing an important role. Adsorbents containing amido groups showed low binding affinity and capacity for GenX, whereas the amine-functionalized polymer had outstanding affinity and capacity for GenX (KL = 8.8 × 104 M-1, QM = 222 mg g-1), underscoring the essential role of electrostatic interactions for removing short-chain and branched PFAS. The amine-containing β-CD polymer exhibited 100-fold higher affinity and twice the capacity (KL = 1.8 × 106 M-1, QM = 457 mg g-1) for PFOA compared to GenX, which are the highest reported values for β-CD polymers. These results highlight the synergistic effects of electrostatic interactions and host-guest interactions in β-CD polymers as important design criteria for efficient removal of anionic PFAS from water. This study further demonstrates broad tunability of crosslinked β-CD polymers and their promise as adsorbents for PFAS remediation.
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U2 - 10.1021/acsmaterialslett.0c00240
DO - 10.1021/acsmaterialslett.0c00240
M3 - Article
AN - SCOPUS:85092151466
SN - 2639-4979
VL - 2
SP - 1240
EP - 1245
JO - ACS Materials Letters
JF - ACS Materials Letters
IS - 9
ER -