Optimization of thermal conditions of sol-gel method for synthesis of TiO2 using RSM and its influence on photodegradation of tartrazine yellow dye. Issue 2 (April 2021) - Souza, Isis P.A.F.
Graphical abstract: Highlights: Thermal treatment effect on the sol-gel method for TiO2 synthesis was investigated. Optimization of thermal conditions was carried out from chemometric tools. The best thermal condition was: temperature 527 °C, heating rate 6 °C min −1, heating time 177 min. TiO2 showed good performance for photodegradation of tartrazine yellow dye. Abstract: The present work reports the use of chemometric tools to investigate the thermal treatment effect on the synthesis of TiO2 from sol-gel method and its photoactivity for photodegradation of tartrazine yellow dye (TY). The thermal parameters as temperature, heating rate and heating time were evaluated from the apparent constant ( kapp ) determined by the photodegradation kinetic of tartrazine dye, which was used as response for central composite rotatable design (CCR). The evaluation of parameter effects on response and the optimization of process were performed via response surface methodology (RSM). The results showed that three parameters have significant influence on the response and there are not interaction effects between them. Additionally, TiO2 that showed the best photoactivity TiO2 (TiO2Op ) was obtained from the following thermal conditions: temperature of 527 °C, heating rate of 6 °C min −1 and heating time of 177 min. Analysis techniques showed significant changes in the textural, morphological, chemical, crystallographic and thermal stability characteristics of TiO2Op, when compared to the synthetized TiO2 with lowest photocatalytic activity. TiO2Op showed band gap energy of 3.04 eV and kinetic parameters of TY photodegradation of kapp 6.26 × 10 −3 min −1 and t1/2 110.7 min.