A next-generation absorbent material with a high affinity for short- and long-chain per- and polyfluoroalkyl substances (PFAS) has recently been granted a patent in the U.S. Developed by Puraffinity Ltd. (London, U.K.; www.puraffinity.com), the material is bottom-up-designed, beginning with a raw substrate, to which functionalized surface coatings are added, explains Puraffinity co-founder and chief product & innovation officer Henrik Hagemann. He emphasizes the significance of using coatings, rather than ligands, for functionalization, which would be much too expensive for large-scale environmental remediation applications. “You can think of the material as a dual-binding adsorbent. There is an electrostatic interaction, and there are hydrophobic and hydrophilic interactions, and this dual-mode interaction basically provides some of the unique benefits,” says Hagemann. These benefits include significantly faster kinetics, smaller equipment footprint, longer lifespan and up to 7 times higher PFAS-removal capacity than traditional petroleum-derived ion-exchange resins. “You can run it in 30 or 45 seconds empty bed-contact time, whereas ion-exchange typically needs three to five minutes,” he notes.
Source: Puraffinity
The material, called Puratech G400, consists of hard, white granules that are around 0.5 mm wide, which are designed to fit into the packed-bed vessels that would typically be used for existing technologies. “We’ve designed the material’s specifications, the actual physical structure of it, to fit into the same paradigm of hydraulic loading and operating conditions as ion-exchange resins, so users can basically keep the same infrastructure,” adds Hagemann.
The company has completed extensive third-party validation of its material in several locations across the U.S. and Germany, showing reproducible performance in continuous-flow tests where the absorbent could provide extremely dilute (~4 parts-per-trillion) PFAS concentrations in streams with high (2–8 ppm) total organic content.
Another differentiator is a focus on end-of-life design and material regeneration. Because the favorable kinetics require a smaller material footprint, the waste-disposal volume is reduced, and Puraffinity is preparing to launch a new generation of the material where PFAS can be unbound via liquid-wash next year.
Puraffinity has been working to significantly scale up its synthesis process, and in the last three months, the company has produced over 400 kg of Puratech G400, having recently received U.K. REACH approval for manufacturing at tonnage scale.