Characterization, adsorption and photocatalytic activity of vanadium-doped TiO2 and sulfated TiO2 (rutile) catalysts: Degradation of methylene blue dye

Sulfated (5 wt.%) TiO2 and non-sulfated TiO2 (rutile) modified by NH4VO3 using incipient wetness impregnation technique to achieve a loading of 2 wt.% V2O5 were thoroughly characterized by means of X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV–vis absorption spectroscopy, N2 sorptiometry, particle size analyzer and pyridine-FT-IR that was used to investigate the acidity of the samples. Degradation of methylene blue (MB) dye was tested for the effectiveness of the samples. The results revealed that MB degradation was highly improved with V supported on TiO2–SO4 and showed a conversion comprises of 98% after UV irradiation (emitting at 400 nm) for 70 min exceeding that of SO4 free TiO2 sample (78%) obtained at the same period of illumination. This was due to the large surface area (345 m2 g−1), small crystallites size, reduced band-gap energy and presence of basic sites namely O2− and OH− moieties those take part in the reaction as additional oxidizing agents. The photocatalytic degradation of MB was found to follow first order rate kinetics. More information on the activity, surface texturing, kinetics and TOC removal were well evaluated, compared and discussed for all samples.

Apparent first order rate constant for the degradation of MB was faster on rutile 2V/TiO2–SO4 catalyst than the sulphate free one. Figure optionsDownload as PowerPoint slide