Sorptive Removal of F-53B from Water by Sodium Dodecyl Sulfate Modified Layered Double Hydroxide

The phase out of perfluorooctane sulfonate (PFOS) promotes the production and use of its alternatives, one of which is chlorinated polyfluorinated ether sulfonate (trade name F-53B). F-53B has been widely detected in various environmental matrices and has been reported to have equal or higher health risks than PFOS. Therefore, developing effective remediation strategies for F-53B removal is essential. In this study, we develop a rapid and effective sorbent, i.e. sodium dodecyl sulfate modified layered double hydroxide (SDS-LDH), for the sorptive removal of F-53B from water. SDS-LDH can remove F-53B within 15 min while having a sorption capacity of over 950 mg/g. Moreover, it can keep ~60% removal of F-53B in the presence of excessive co-existing CO₃^2- (the molar ratio of CO₃²-/F-53B is 28534) which has the strongest host−guest electrostatic interactions with SDS-LDH. Sorption mechanisms of F-53B by SDS-LDH include ion pairing/exchange, hydrogen bond and hydrophobic binding. The results of density functional theory highlight the vital role of hydroxy groups in SDS-LDH, which contribute to the satisfactory removal of F-53B by SDS-LDH. In addition, sodium dodecyl sulfate can offer extra active sites for F-53B via a weak hydrogen bond as C-F/Cl…H.