Potential application of novel TiO2/β-FeOOH composites for photocatalytic reduction of Cr(VI) with an analysis of statistical approach

In this paper, four TiO₂/β-FeOOH photocatalysts were synthesized by a simple deposition–precipitation method and characterized by X-ray diffraction, fourier transform infrared, scanning electron microscope and transmission electron microscope. The characterization showed the presence of nano-sized β-FeOOH particles on the TiO₂ support. The photocatalytic efficiency of the catalysts was examined on the Cr(VI) reduction under ultraviolet irradiation in aqueous suspension. The photocatalyst denoted as 25TiO₂/β-FeOOH appeared to be most efficient, which is due to effectively inhibiting the recombination of photoinduced electrons and holes. A 2⁴ factorial design methodology was employed to evaluate the statistically important operating conditions (pH of the solution, loading of catalyst, Cr(VI) concentration and reaction time) and their interactions on the photocatalytic reduction efficiency of Cr(VI) over 25TiO₂/β-FeOOH.

Keywords
Chromium reduction; Photocatalysis; TiO₂/β-FeOOH; Composites; Factorial design