Fabrication of α-Fe₂O₃/TiO₂ bi-functional composites with hierarchical and hollow structures and their application in water treatment

The α-Fe₂O₃/TiO₂ bi-functional composites with hierarchical and hollow structures are fabricated through a hydrothermal route. The adsorption performance and photocatalytic activity of the composites towards Pb²⁺ are investigated in this work. Different adsorption kinetics models and equilibrium models are used to explore the adsorption behavior of hierarchical α-Fe₂O₃/TiO₂ hollow spheres. Experimental data show that adsorption kinetics of the hierarchical α-Fe₂O₃/TiO₂ hollow spheres can be fitted well by the pseudo-second-order model, while the isothermal data can be perfectly described by the Langmuir adsorption model. The maximum adsorption capacity of the hierarchical α-Fe₂O₃/TiO₂ hollow spheres is 32.36 mg g⁻¹. Moreover, the hierarchical α-Fe₂O₃/TiO₂ hollow spheres possess photocatalytic oxidation character under simulated solar light irradiation. The results demonstrate that the hierarchical α-Fe₂O₃/TiO₂ hollow spheres, as effective and cheap materials, can be applied to the removal of heavy metal ions from wastewater