Hydrothermal synthesized magnetically separable mesostructured HTiO/γ-FeO nanocomposite for organic dye removal via adsorption and its regeneration/reuse through synergistic non-radiation driven HO activation.

Hydrogen titanate (HTiO) nanotubes/nanosheets (HTN) are emerging class of adsorbent material which possess unique property of activating hydrogen peroxide (HO) to generate the reactive oxygen species (ROS), such as superoxide radical ions (O) and hydroxyl radicals (·OH), effective in the decomposition of surface-adsorbed dye. However, HTN are non-magnetic which create hurdle in their effective separation from the treated aqueous solution. To overcome this issue, magnetic nanocomposites (HTNF) composed of HTN and maghemite (γ-FeO) nanoparticles have been processed by subjecting the core-shell magnetic photocatalyst consisting of γ-FeO/silica (SiO)/titania (TiO), having varying amounts of TiO in the shell to the hydrothermal conditions. HTNF-5 magnetic nanocomposite consisting of 31 wt% HTiO, typically having nanotube morphology with the highest specific surface area (133 m g) and pore-volume (0.22 cm g), exhibits the highest capacity (74 mg g) for the adsorption of cationic methylene blue (MB) dye from an aqueous solution involving the electrostatic attraction mechanism and pseudo-second-order kinetics. Very fast magnetic separation followed by regeneration of HTNF-5 magnetic nanocomposite has been demonstrated via non-radiation driven HO activation. It has been ascertained for the first time that the underlying mechanism of dye decomposition involves the synergy effect between the constituents of HTNF magnetic nanocomposite.