TiO₂ Synthesis by the Pechini's Method and Application for Diclofenac Photodegradation^†

In this work, the effect of the calcination temperature on the TiO₂ synthesis using Pechini's method was reported. The adopted calcination temperatures were 500, 600, and 700°C. XRD measurements indicated the composition of crystalline phases, and from there, the conversion of the anatase phase to rutile. TiO₂ Evonik^® was used as a reference standard and sodium diclofenac as a standard for photodegradation assessment. The average crystalline size increased. In both cases, this trend accompanied the increase in calcination temperature. The optical properties were performed using diffuse UV-Vis reflectance. Results obtained indicated maximum absorption wavelength values more intense and displaced to the visible region. Also, the estimated band gap energy values decreased. The photocatalytic performance of TiO₂ samples was superior to the reference catalyst (TiO₂ Evonik^® ). Especially in the first 10 minutes, the comparative photodegradation was up to approximately 58% higher. The photodegradation kinetic constants were also higher, and by comparison, up to approximately 73% higher. Toxicity measurements, using Artemias salina, also indicated similar decay behavior in the first 10 minutes, with a performance of up to approximately 60%.