Remarkable Ti-promotion in vanadium doped anatase titania for methylene blue adsorption in aqueous medium

We report here the synthesis of vanadium (5-20 at%) doped titania and the pristine oxides via surfactant assisted coprecipitation method using cetyltrimethylammonium bromide as the surfactant and investigated their adsorption behavior towards hazardous methylene blue dye. The formation of anatase phase in all the doped materials is confirmed by the powder x-ray diffraction (P-XRD) analysis as corroborated by the Fourier transform-infrared (FT-IR) analysis, with particle sizes in the range 8-11 nm. Pure titania doesn't show any adsorption property, but its presence enhances the adsorption property of vanadia considerably suggesting a promoting role of titania in the doped materials. The 10 at.% V-doped material, V0.1Ti0.9O2 is found to exhibit the best adsorption behaviour. The low resolution transmission electron microscopy studies reveal homogeneous nature, while ring type electron diffraction pattern suggests polycrystalline nature of the material. The high resolution transmission electron microscopy analysis suggests formation of single phase oxide. Kinetic and equilibrium studies have revealed the pseudo-second-order kinetics and Langmuir isotherm nature for this physisorption process. The pH dependency and recycling ability of this material have been discussed. Finally, X-ray photoelectron spectroscopy, FT-IR and P-XRD studies have been applied to understand the mechanism of regeneration of the material.