Photocatalytic destruction of Escherichia coli in water by V₂O₅ /TiO₂

Abstract

Vanadia modified titania (V₂O₅/TiO₂) photo-catalysts are prepared by incipient wet impregnation method using aqueous ammonium metavanadate and anatase (Aldrich) titania. Titania with various loading concentrations of vanadia from 0 to 10 wt.% have been prepared and characterized by X-ray diffraction (XRD), Thermogravimetry (TGA), Laser Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), UV-Visible Spectrophotometry and Transmission Electron Microscopy (TEM). XRD study reveals that vanadia loading on titania does not bring any phase change of titania, however, diffuse (UV-Vis) reflectance spectra show that absorption edge of titania shifted from UV to visible region. TEM confirms that titania and vanadia modified titania have the particle size below 50 nm. XPS shows alteration of 2p₃/₂ peak of V(V) in the V₂O₅/TiO₂ samples whereas no such change is noticed in pure V₂O₅ indicating the interaction between vanadia and titania support. Antibacterial activity of each sample has been investigated against Escherichia coli present in the water under both UV-Visible irradiation and UV alone. V₂O₅/TiO₂ catalysts exhibit better photocatalytic effect than the unmodified titania and pure V₂O₅. It is observed that with increasing loading concentrations of V₂O₅ from 0 to 10 wt.% on titania support, the photocatalytic annihilation of E.coli is also increased and found to be little higher under UV alone than the UV-Visible irradiation.