Photocatalytic efficiency of Fe_2O_3/TiO_2 for the degradation of typical dyes in textile industries: Effects of calcination temperature and UV-assisted thermal synthesis

摘要

The inadequate management practices in industrial textile effluents have a considerable negative impact on the environment and human health due to the indiscriminate release of dyes. Photocatalysis is one of the diverse advance oxidation processes (AOPs) and titanium dioxide (TiO_2) is recognized for its high oxidation and reduction power. A composite photocatalyst of Fe_2O_3/TiO_32 is synthesized using different mass ratios of Fe:TiO_2 to improve its photoactivity. The composite photocatalyst is calcined at 300 -900 ℃. Their photocatalytic activity for the degradation of Congo red (CR) and methyl orange (MO) is investigated by total organic carbon (TOC) analysis. The formation and characterization of the as-prepared composite are studied by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). The effect of calcination temperature on the composite Fe_2O_3/TiO_2 pho-tocatalyst is investigated using Fourier transform infrared spectroscopy (FTIR). The photocatalytic activity and the phase conversion are studied by X-ray diffraction (XRD). The specific surface area of photo-catalysts at different calcination temperatures is investigated based on Brunauer-Emmett-Teller (BET) surface area analysis. Results show that at an optimum calcination temperature of 300 °C for the photocatalyst preparation, the specific surface area is maximum and the photocatalyst has the highest photoactivity. Thus, the degradation of organic materials reaches 62.0% for MO and 46.8% for CR in the presence of Fe_2O_3/TiO_2 (0.01 w:w Fe:TiO_2) calcined at 300 °C with the highest specific surface area (98.73 m~2/g). The transformation of TiO_2 from anatase to rutile is facilitated by high temperature and high concentration of iron while high crystallization and particle size increase occur. An optimum calcination temperature of 300 ℃ is found at which the degradation of typical dyes in textile industries is maximum.