Efficient separation of per- and polyfluoroalkyl substances (PFAS) from water by aminated polyacrylamide hydrogel foam

Emerging per- and polyfluoroalkyl substances (PFAS) are highly toxic chemicals with extraodinary stability in the aquatic environment. Highly efficient adsorbents are in urgent need to address the environmental challenges caused by PFAS. Herein, we developed a novel aminated foam adsorbent with high affinity for PFAS adsorption through polymerization, amination and pyrolyzation. For initial 1 μg/L perfluorooctanoic acid (PFOA) solution, more than 97.9 % removal efficiency could be obatined with a rapid equilibration time of ∼ 15 min. The elevated adsorption efficiency could be explained by the synergetic effect of electrostatic/hydrogen bonding and hydrophobic interaction, while the increase of specific surface area (SSA) also has a positive effect on PFOA adsorption. Furthermore, the sythesized polyacrylamide-polyaniline material (pyrolyzed at 301℃, PAM-PANI-2) exhibited high adaptability to different environmental influencing factors, including pH and co-existed organic matters, and presented excellent adsorption removal ability for other common PFAS except for PFOA. Moreover, it is worth noting that this foam material has advantages in regeneration compared to traditional powder adsorbents, without complicated procedures such as centrifugation and filtration. These results indicate that aminated PAM polymers are promising adsorbents in remediations of trace PFAS-contaminated water, which can give new insights to the design and application of novel polymer materials of PFAS treatments.