Photocatalytic degradation of 4-nitrophenol using TiO2 + Fe2O3 and TiO2/Fe2O3-supported bentonite as heterogeneous catalysts

TiO2/natural hematite-supported bentonite (TiNHB) was successfully synthesized as a heterogeneous catalyst for photodegradation of 4-nitrophenol (4-NP) in aqueous solution. Supporting on TiO2/hematite rendered a significant increase in specific surface area of bentonite. X-ray diffraction and Fourier-transform infrared spectroscopy analyses confirmed the presence of both TiO2 and Fe2O3 nanoparticles in the TiNHB catalyst. The photocatalytic performance of TiNHB was investigated using reduction of 4-nitrophenol (4-NP) as model reaction. The results showed that TiNHB converted nearly 98 % of 4-NP under UV254nm irradiation with optimum operating conditions of 0.025 g/L TiNHB, pH 3, and 20 mg/L 4-NP. The reaction kinetics of the photocatalytic reduction of 4-NP were studied by UV-Vis spectrophotometry, and the apparent rate constant was determined for comparison with TiO2 + Fe2O3. This work is expected to shed new light on the development of new photocatalysts for removal of environmental pollutants.