Synthesis and\nEvaluation of Cationic Porphyrin-Based\nOrganic Nanocages for the Removal of 38 PFAS from Water: Experimental,\nTheoretical, and Eco-toxicological Insights

Per- and polyfluoroalkyl substances (PFAS), persistent\npollutants\nfound in water sources worldwide, pose significant challenges to conventional\nremediation methods. This study presents a one-pot, high atom-economy\nsynthesis of porphyrin-based cationic nanocages (oNCs) as a selective,\nrapid and efficient solution for PFAS removal, addressing critical\ngaps in current water treatment technologies. Using liquid chromatography–tandem\nmass spectrometry (LC-MS/MS), the nanocages<b>[oNC]8PF</b><sub><b>6</b></sub>, <b>[Co</b><sup><b>2+</b></sup><b>-oNC]8PF</b><sub><b>6</b></sub>, and <b>[Co</b><sup><b>3+</b></sup><b>(NO)-oNC]8PF</b><sub><b>6</b></sub>were evaluated for their ability to sorb a\nmixture of 38 PFAS, including emerging contaminants like GenX, from\nvarious water matrices at a concentration of 50 ng/mL. The nanocages\nachieved exceptional PFAS removal efficiencies, with optimal results\nobtained when <b>[oNC]8PF</b><sub><b>6</b></sub> and <b>[Co</b><sup><b>2+</b></sup><b>-oNC]8PF</b><sub><b>6</b></sub> were combined in a 1:4 ratio. This mixture created\na synergistic effect, enabling the sorption of both short- and long-chain\nPFAS, achieving average removal efficiencies of 90% in Nanopure and\ngroundwater, and 80% in influent sewage. The nanocage mixture consistently\noutperformed activated carbon, particularly in complex matrices such\nas influent sewage, where activated carbon presented lower efficiency,\nespecially for perfluoroalkane sulfonamido substances. The nanocages\nreached sorption equilibrium within 15 min and maintained performance\nacross multiple methanolic regeneration cycles, highlighting their\noperational durability. NMR spectroscopy and computational studies\nrevealed that PFAS sorption occurs via hydrophobic and electrostatic\ninteractions, as well as partial intercalation, with selectivity for\nPFAS molecules bearing sulfonate and sulfonamide head groups and carbon\nchain lengths of five or more. Early stage eco-toxicological assessments\nconfirmed the environmental safety of these nanocages, showing no\nadverse effects below a concentration of 0.005 μM. By combining\nrapid PFAS removal with modular, scalable and sustainable material\nsynthesis, this study sets a new direction for developing precise,\nenvironmentally responsible PFAS water treatment solutions.