Ultra-rapid removal of per- and poly fluorinated alkyl substances from water using cyclodextrin polymer networks

Per- and poly fluorinated alkyl substances (PFASs) are emerging contaminants and raising great concern due to their pervasive presence in water resources. Among various treatment techniques, adsorption is the most promising treatment solution for PFASs removal. Herein, we developed a β-cyclodextrin (β-CD)-based polymer (β-CD-TriPod) crosslinked with tripodal amine to demonstrate the synergetic effects in superior adsorption of both short- and long-chain per- and polyfluoroalkyl substances (PFASs). Kinetics studies showed rapid adsorption (~100% for nine PFASs at 1 µg L^-1, except PFBA, and >86% at 200 µg L^-1 individually) within two minutes. Isotherm results showed exceptional adsorption affinity and capacity, with K_L = 0.310 ± 0.180 L mg^-1, q_m = 246.20 ±14.80 mg g^-1 for PFBS, and K_L = 0.980 ± 0.260 L mg^-1, q_m = 587.10 ± 54.50 mg g^-1 for PFOS, significantly outperforming traditional activated carbons (ACs) and resins. The adsorbent also exhibited excellent regeneration and reusability, maintaining stable performance (>94%) over five consecutive adsorption-desorption cycles. Additionally, it performed effectively in PFASs-spiked real industrial wastewater with 55-100% removal efficiencies, regardless of the presence of co-contaminants. The adsorption mechanism confirmed the combined role of hydrophobic inclusion within β-CD cavities and electrostatic interactions with amines groups using elemental mapping, composition and FTIR techniques. Overall, this work demonstrates advanced molecular design strategies for rapid PFASs removal, establishing β-CD-TriPod as a highly regenerable and promising adsorbent for the rapid and efficient treatment of PFASs-contaminated water and industrial wastewater.