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Well-dispersed TiO2 nanoparticles anchored on Fe3O4 magnetic nanosheets for efficient arsenic removal

Deng, Min, Wu, Xiaodong, Zhu, Aimei, Zhang, Qiugen, Liu, Qinglin
Journal of environmental management 2019 v.237 pp. 63-74
adsorbents, adsorption, arsenic, arsenites, hydrogen, ions, iron oxides, magnetism, nanocomposites, nanoparticles, nanosheets, oxidation, pH, phosphates, photocatalysis, silicates, surface area, titanium dioxide
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 Fe3O4@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 Fe3O4 sheets. The resultant Fe3O4@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 Fe3O4@TiO2 sheets with unique nanostructure could be a promising efficient adsorbent for arsenic removal.