Collectable and Recyclable Mussel-Inspired Poly(ionic liquid)-Based Sorbents for Ultrafast Water Treatment

We report a green method to graft directly poly­(ionic liquid) onto polydopamine-modified magnetic-responsive Fe3O4 nanoparticles through an organic solvent-free process of self-initiated photografting and photopolymerization. PIL@PDA@Fe3O4 nanocomposite is characterized by transmission electron microscopy, attenuated total reflection-infrared intensity, X-ray photoelectron spectroscopy, and thermal gravimetric analyzer. The nanoparticles can be used for removal of methylene blue (MB) from water. The adsorption is ultrafast, with a maximum MB adsorption capacity of 72.5 mg/g. A selective adsorption property of PIL@PDA@Fe3O4 is also demonstrated by separation of cationic dyes from anionic dyes in water. The particles can be collected by a magnet and be regenerated by washing with salt solution after adsorption. The results show negligible change in the adsorption and desorption efficiency after 5 cycles. This work demonstrates the potential of PDA as an initiator for photografting and photopolymerization of PIL from surfaces separation applications.