Tetrafluoroterephthalonitrile-crosslinked β-cyclodextrin polymers for efficient extraction and recovery of organic micropollutants from water

Reduction of a Tetrafluoroterephthalonitrile‐β‐Cyclodextrin Polymer to Remove Anionic Micropollutants and Perfluorinated Alkyl Substances from Water

“…We found that 1 exhibited relatively high log K D values for cationic MPs,a long with neutral compounds that bind to CDs well, which is consistent with previous reports [16,32] and observations (Figure 3). [13,17] All 18 cationic substances exhibited log K D values greater than 2on polymer 1.Incontrast, 21 of 25 anionic substances and all 10 anionic PFASs exhibited relatively low log K D values between À0.5 and 1.0 on polymer 1.These low affinities make polymer 1 an ineffective adsorbent for most anionic MPs at environmentally relevant concentrations and economically reasonable doses of 1.Incontrast, polymer 2 strongly binds anionic substances,with 21 of 25 exhibiting log K D values > 2.6 and all ten anionic PFASs exhibiting log K D values between 2.8-4.0. However,p olymer 2 binds cationic MPs more weakly with log K D values for 16 of 18 cationic MPs between À0.5-1.5.…”

“…β‐cyclodextrin (β‐CD)‐based polymers (CDPs) with aromatic crosslinkers have shown promise to remove MPs from water . For example, a CDP crosslinked by tetrafluoroterephthalonitrile (TFN), was formed as a permanently porous network ( 1 , Figure ) that rapidly removes many MPs from water, resists fouling by natural organic matter, and can be regenerated . A study of the binding of 83 MPs under environmentally relevant concentrations revealed that 1 rapidly removes many cationic and neutral MPs but shows poor affinity for most anionic MPs .…”

“…[11,12,14,16] Forexample,aCDP crosslinked by tetrafluoroterephthalonitrile (TFN), was formed as apermanently porous network (1,F igure 1) that rapidly removes many MPs from water, [11] resists fouling by natural organic matter, [13,14] and can be regenerated. [17] Astudy of the binding of 83 MPs under environmentally relevant concentrations revealed that 1 rapidly removes many cationic and neutral MPs but shows poor affinity for most anionic MPs. [13] This selectivity for cations was later attributed to anionic phenolate groups introduced to the TFN crosslinkers during the polymerization.…”

Nitrile Reduction Reverses the Micropollutant Uptake Selectivity of a Tetrafluoroterephthalonitrile-β-Cyclodextrin Polymer

“…We found that 1 exhibited relatively high log KD values for cationic MPs, along with neutral compounds that bind to CDs well, which is consistent with previous reports 16,32 and observations (Fig 3). 13,17 MPs between -0.5-1.5. These findings demonstrate that the structure of the crosslinker plays a major role in the selectivity of CD-based adsorbents and that strategies to incorporate charged groups, either during the polymerization (phenolates), 16,27 or by post-polymerization modification Polymer 2 removes PFOA and PFOS rapidly, as the combined residual PFOA + PFOS Figure 3.…”

“…11,12,14,16 For example, a CDP crosslinked by tetrafluoroterephthalonitrile (TFN), was formed as a permanently porous network (1, Fig 1) that rapidly removes many MPs from water, 11 resists fouling by natural organic matter, 13,14 and can be regenerated. 17 A study of the binding of 83 MPs under environmentally relevant concentrations revealed that 1 rapidly removes many cationic and neutral MPs, but removal of anionic MPs was variable and relatively low. 13 This selectivity for cations was attributed to anionic phenolate groups introduced to the TFN crosslinkers during the polymerization.…”