Water disinfection through photoactive modified titania

• Nitrogen doping strongly shifts the absorption edge of titania from UV to visible region.
• Sulpur doping decreases the crystallinity of titania whereas nitrogen does not affect it.
• Nitrogen occupies at both substitutional and interstitial position of titania lattice.
• N-TiO2 exhibits superior water disinfection property than S-TiO2 and TiO2.

TiO2, N-TiO2 and S-TiO2 samples have been prepared by various chemical methods. These samples were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), Laser Raman spectrometer, UV–Visible spectrophotometer, field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). X-ray powder diffraction study reveals that all three samples are single anatase phase of titania and the crystallinity of titania decreases with sulphur doping whereas nitrogen doping does not affect it. UV–Visible (diffuse) reflectance spectra shows that doping of titania with nitrogen and sulphur shift the absorption edge of titania from ultraviolet to visible region. XPS study confirms that both nitrogen and sulphur are well doped in the titania lattice. It is observed that nitrogen occupies at both substitutional and interstitial position in the lattice of titania. FE-SEM and TEM studies demonstrate that the particles are below 50 nm range. It is found that S and N doping of titania increased its water disinfection property in the order TiO2 < S-TiO2 < N-TiO2 under 8 W UV/UV–Visible light irradiation.