Improvement of the structural, morphology, and optical properties of TiO2 for solar treatment of industrial wastewater

Hydrothermal preparation of pure anatase TiO2 with hybrid nano and micro-morphologies directly from titania sol under acidic condition in the absence of any additives or templates has rarely been reported. The present work has found that the post-hydrothermal treatment at 200 degrees C for different times (6, 12, 24, and 36 h) of titania sol under an acidic environment affected strongly on the structural, morphology, and optical properties of TiO2. A single-crystalline anatase phase with high surface area was obtained. The TEM results showed that shape of TiO2 nanoparticles could be manipulated by post-hydrothermal treatment. The increasing of hydrothermal time (pH 2.5) significantly altered the morphology of TiO2 from pure aggregated nanospherical shape (6 h) into branched micro-flowers as a major shape in addition to nanorod, nanocube, and nanosphere shapes (24 h). Shape-controlled TiO2 nanoparticles showed a red shift in UV-Vis light reflectance spectra as compared to TiO2 nanoparticles obtained without any hydrothermal treatment. The photoluminescence measurements confirm that hydrothermal treatment significantly decrease the electron-hole recombination chance in the obtained TiO2. The fluorescent probe method was used for evaluation of the photo-oxidative activity of different TiO2 nanomaterials. The highly active TiO2 nanoparticle (hydrothermally treated for 24 h) was applied for industrial wastewater treatment using solar radiation as a renewable energy source.