Insights into the Understanding of Adsorption Behaviors of Legacy and Emerging Per- and Polyfluoroalkyl Substances (PFASs) on Various Anion-Exchange Resins

Per- and polyfluoroalkyl substances (PFASs) have received extensive attention due to their various harmful effects. In this study, the adsorptive removal of 10 legacy and emerging PFASs by four anion-exchange resins (including gel and macroreticular resins) were systematically investigated. Our results showed that the capacities of resins absorbing PFASs were ranked in the following order: gel strong base HPR4700 (297 similar to 300 mu g/g) approximate to macroreticular strong base S6368 (294 similar to 300 mu g/g) approximate to macroreticular weak base A111S (289 similar to 300 mu g/g) > gel weak base WA10 (233 similar to 297 mu g/g). Adsorption kinetic results indicated that the adsorption process might involve chemical and Henry regime adsorption or reaction control. Intraparticle diffusion was probably the major removal step. Co-existing fulvic acid (0.5, 1, 5 mg/L) and inorganic anions (5 mg/L of sulfate, carbonate, bicarbonate) would hinder the PFAS removal by resins with WA10 showing the highest inhibition rate of 17% and 71%, respectively. The adsorption capacities of PFBA decreased from 233 mu g/g to 194 mu g/g, and from 233 mu g/g to 67 mu g/g in the presence of fulvic acid and inorganic anions, respectively. PFASs were more easily removed by HPR4700, S6368, and A111S under neutral and alkaline environment. Moreover, WA10 was not able to remove PFASs under an alkaline medium. This study offered theoretical support for removing PFASs from aqueous phases with various resins.

Automated summary

This study systematically investigated the adsorptive removal of 10 PFASs by four anion-exchange resins. The results showed that the capacities of resins absorbing PFASs varied, with gel strong base HPR4700, macroreticular strong base S6368, and macroreticular weak base A111S showing higher capabilities compared to gel weak base WA10. The presence of fulvic acid and inorganic anions hindered the PFAS removal, with WA10 being the most affected. HPR4700, S6368, and A111S were more effective in removing PFASs under neutral and alkaline conditions, while WA10 was not able to remove PFASs under alkaline medium. This study provides theoretical support for the removal of PFASs from aqueous phases using different resins.