Thermosensitive hydrogels for efficient removal of perfluorooctanesulfonic acid

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants that endanger the environment and human health. Adsorption can be an effective method for removing PFAS from water owing to its high efficiency. In this study, thermosensitive hydrogels were prepared and used for removal of perfluorooctanesulfonic acid (PFOS). As the pH value of solutions increased, the adsorption capacity decreased significantly, and the maximum adsorption capacity (476.5 mg/g) was attained at pH = 3. Hydrogen bonding interactions and electrostatic interactions might be involved for removal of PFOS. Desorption of PFOS form the loaded-hydrogel could be achieved in distilled water at 323 K without the use of chemical reagents. After five cycles of adsorption-desorption processes, the adsorption capacity of the hydrogel maintained 95 % of the original adsorption capability. This study developed a general method for creating thermosensitive hydrogels with excellent adsorption performance for PFOS, and provided an environmentally friendly method for recycling used hydrogels.