Selective and Fast Adsorption of Perfluorooctanesulfonate from Wastewater by Magnetic Fluorinated Vermiculite

A novel magnetic fluorinated adsorbent with selective and fast adsorption of perfluorooctanesulfonate (PFOS) was synthesized via a simple ball milling of Fe₃O₄ and vermiculite loaded with a cationic fluorinated surfactant. The loaded Fe₃O₄ nanoparticles increased the dispersibility of fluorinated vermiculite (F-VT) in water and allowed the magnetic separability. The nanosized Fe₃O₄ was homogeneously embedded into the adsorbent surfaces, improving the hydrophilicity of F-VT external surface, and this hybrid adsorbent still kept the hydrophobic fluorinated interlayer structure. With this unique property, Fe₃O₄-loaded F-VT has very fast and selective adsorption for PFOS in the presence of other compounds, due to the fluorophilicity of C-F chains intercalated in the adsorbent interlayers. This novel adsorbent has a high sorption capacity for PFOS, exhibiting PFOS removal from fire-fighting foam wastewater that is much higher than that of powdered activated carbon and resin due to its high selectivity for PFOS. The used Fe₃O₄-loaded F-VT was successfully regenerated by methanol and reused five times without reduction in PFOS removal and magnetic performance. The Fe₃O₄-loaded F-VT demonstrates promising application for PFOS removal from real wastewater.