Comparison of Zn–Al and Mg–Al layered double hydroxides for adsorption of perfluorooctanoic acid

Per-and polyfluoroalkyl substances (PFAS), a large class of synthesized chemicals, are persistent in nature and generally recalcitrant to conventional chemical biological treatment. Adsorption is considered an economical practical method for PFAS Layered double hydroxides (LDHs) represent promising mineral-based adsorbents removal because the highly positive charge their structural layers. In this research, performance two representative LDHs with varied cation compositions, namely Zn–Al Mg–Al LDHs, were investigated compared perfluorinated carboxylic acids (PFCAs) emphasis on perfluorooctanoic acid (PFOA). LDH showed high efficiency medium- long-chain PFCAs (i.e., C ≥ 7), performed consistently better than LDH. Based detailed adsorption kinetics isotherm studies toward PFOA, higher capacity, stronger affinity, faster Presence natural organic matter had minimal impact PFOA by LDH, but sulfate severely inhibited adsorption. Combined results aqueous experiments sorbent characterization suggested that electrostatic interactions may be primary mechanism onto LDHs. Our composition can have significant effect PFCA removal.