Using one-step facile and solvent-free mechanochemical process to synthesize photoactive Fe2O3-TiO2 for treating industrial wastewater

In this present study, Fe2O3-TiO2 photocatalyst was synthesized and used to degrade real industrial wastewater, namely pulp and paper mill effluent (PPME). Fe2O3-TiO2 was synthesized via ball milling at ambient conditions without incorporating any solvent. Comprehensive characterization studies and photocatalytic evaluations of the synthesized Fe2O3-TiO2 were conducted in this study. It was verified that Fe2O3-TiO2 possessed crystalline structures of γ-Fe2O3, anatase and rutile TiO2. Also, a good dispersion of Fe and O elements within the TiO2 framework was attained. A detection of FeOTi bond elucidated a substitution of Ti4+ by Fe3+ in the TiO2 lattice sites through mechanical milling, which ultimately enhanced the photocatalytic activities of Fe2O3-TiO2. Moreover, Fe2O3-TiO2 exhibited enhanced catalytic properties in terms of specific surface area (58.40 m2/g), band gap (2.95 eV), and charge separation in comparison with commercial P25. The present work also proved that both characteristics and photoactivity of Fe2O3-TiO2 were significantly affected by its synthesis conditions (milling time, milling speed, and Fe2O3 loading). The highest treatment efficiency of PPME (62.3% of chemical oxygen demand or COD removal) was achieved using Fe2O3-TiO2, which was synthesized at 20 min, 250 rpm and 1 mol% of milling time, milling speed, and Fe2O3 loading, respectively. Noticeably, the photoactivity of the Fe2O3-TiO2 was more superior to P25 (40.6% of COD removal). This study proved that mechanochemical process enabled the green synthesis of Fe2O3-TiO2 that could be used in the treatment of real industrial wastewater.