Síntese do pó de ZrTiO4 pelo método dos precursores poliméricos e sua atividade fotocatalítica

Abstract

The research had as a way to synthesize the Zirconia Titanate (ZrTiO4), based on the method of polymeric precursors and investigate its photocatalytic potential in the degradation of dyes linked to textile production. To obtain ZrTiO4, solutions of titanium citrate and zirconium citrate were prepared in a 3:1 molar ratio of citric acid / metal. After synthesis, the polymeric resin obtained was subjected to calcination at 300 ºC for 3 hours and the resulting powder, called “precursor”. By X-ray diffraction, it was possible to observe that the precursor powder is characteristic of amorphous material. The precursor powder was subjected to heat treatments at different prices from 600 to 1400 °C for 3 hours with a heating rate of 10 ºC/min. Differential Scanning Calorimetry detected a peak of crystallization at 700 ºC, which was confirmed by X-Ray Diffraction, the temperature of formation of crystalline ZrTiO4, however, it presents a small amount of secondary phase. At 800 ºC it was possible to obtain the single-phase ZrTiO4. With the increase in temperature, a decrease in the lattice parameter b, indicative of defects in the crystalline lattice, was observed by Rietveld refinement and, by Scherrer calculation, the average crystalline size increased from 29.5 to 73.2 nm. A morphological analysis showed that at lower temperatures there was the formation of nanoparticles and with the rise in temperature, the process of sintering and densification begins, with better definition of grains and grain contours, increasing the size of particles. Photocatalytic tests were carried out on calcined at 800 ºC and 1400 ºC with the dyes Rhodamine B and Methylene Blue. The sample treated at 800 °C showed 32 and 46% degradation/discoloration of Rhodamine B and Methylene Blue dyes, while the sample treated at 1400 °C showed 22 and 30% degradation/discoloration of specific dyes, indicating that the calcination temperature has a direct influence on the photocatalytic activity of the ZrTiO4 catalyst.