Cyclodextrin-Functionalized Fe₃O₄@TiO₂: Reusable, Magnetic Nanoparticles for Photocatalytic Degradation of Endocrine-Disrupting Chemicals in Water Supplies

Water-dispersible, photocatalytic Fe₃O₄@TiO₂ core–shell magnetic nanoparticles have been prepared by anchoring cyclodextrin cavities to the TiO₂ shell, and their ability to capture and photocatalytically destroy endocrine-disrupting chemicals, bisphenol A and dibutyl phthalate, present in water, has been demonstrated. The functionalized nanoparticles can be magnetically separated from the dispersion after photocatalysis and hence reused. Each component of the cyclodextrin-functionalized Fe₃O₄@TiO₂ core–shell nanoparticle has a crucial role in its functioning. The tethered cyclodextrins are responsible for the aqueous dispersibility of the nanoparticles and their hydrophobic cavities for the capture of the organic pollutants that may be present in water samples. The amorphous TiO₂ shell is the photocatalyst for the degradation and mineralization of the organics, bisphenol A and dibutyl phthalate, under UV illumination, and the magnetism associated with the 9 nm crystalline Fe₃O₄ core allows for the magnetic separation from the dispersion once photocatalytic degradation is complete. An attractive feature of these “capture and destroy” nanomaterials is that they may be completely removed from the dispersion and reused with little or no loss of catalytic activity