Hydrothermal synthesized magnetically separable mesostructured H 2 Ti 3 O 7 /γ-Fe 2 O 3 nanocomposite for organic dye removal via adsorption and its regeneration/reuse through synergistic non-radiation driven H 2 O 2 activation.

Hydrogen titanate (H2 Ti3 O7 ) nanotubes/nanosheets (HTN) are emerging class of adsorbent material which possess unique property of activating hydrogen peroxide (H2 O2 ) to generate the reactive oxygen species (ROS), such as superoxide radical ions (O2 .- ) 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-Fe2 O3 ) nanoparticles have been processed by subjecting the core-shell magnetic photocatalyst consisting of γ-Fe2 O3 /silica (SiO2 )/titania (TiO2 ), having varying amounts of TiO2 in the shell to the hydrothermal conditions. HTNF-5 magnetic nanocomposite consisting of 31 wt% H2 Ti3 O7 , typically having nanotube morphology with the highest specific surface area (133 m2  g-1 ) and pore-volume (0.22 cm3  g-1 ), exhibits the highest capacity (74 mg g-1 ) 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 H2 O2 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.