A comparison between alkaline earth metal titanates for application as photocatalysts in wastewater treatment

The alkaline earth metal titanates are ternary oxides with remarkable properties and applications. We studied the optical and photocatalytic properties of three alkaline earth metal (Ca, Sr, Ba) titanates obtained by sol-gel method, in order to be used in the treatment of wastewaters. The optical properties of titanates were determined by UV-visible and photoluminescence spectroscopy. The band gap energies were calculated using Tauc equation. The morphology of powders was evidenced by scanning electron microscopy. The photocatalytic properties were tested in the bleaching of Congo red solutions. The titanates have a satisfactory photocatalytic activity towards the azo dye, the most efficient photocatalyst being BaTiO 3 (a photocatalytic activity of 49.11%, after 120 min).