Well-dispersed TiO 2 nanoparticles anchored on Fe 3 O 4 magnetic nanosheets for efficient arsenic removal.

Magnetic iron-titanium binary oxide as an effective adsorbent for arsenic contaminant is a challenge primarily because of their bulk structure and agglomeration effect. Herein, a novel and uniform sandwich-like magnetic Fe3 O4 @TiO2 sheets were synthesized by utilizing a facile strategy involving amorphous-to-crystalline transformation and reduction in H2 , to achieve dispersed anatase TiO2 nanoparticles with a small size of ∼8 nm anchored on Fe3 O4 sheets. The resultant Fe3 O4 @TiO2 sheets nanocomposite possessing a high specific surface area of ∼89.4 m2  g-1 and available magnetic susceptibility of ∼20.0 emu g-1 , significantly enhanced the photocatalytic oxidation property of arsenite and considerable adsorption capability for arsenic removal. The adsorption capacities of As(V) and As(III) with UV-assisted from adsorption experimental results were 36.36 and 30.96 mg g-1 , respectively, while the residual concentrations for both As(V) and As(III) were lower than the strict limit of 10 μg L-1 . Adsorption equilibriums were almost reached within 45 min. In addition, the adsorbent exhibited excellent stability over a broad pH range of 3-9 and still maintained great removal efficiency after five time regeneration cycles. Furthermore, except for silicate and phosphate, the extremely weak inhibiting influences of common co-existing ions in arsenic removal process, demonstrated that the developed magnetic Fe3 O4 @TiO2 sheets with unique nanostructure could be a promising efficient adsorbent for arsenic removal.