Coprecipitados de alumínio e cério com 8-hidroxiquinolina: obtenção e comportamento térmico

Abstract

The present study had as focus to evaluate the influence of the PH variables, temperature and time of agitation to obtain and the thermal behavior of co-precipitation of aluminum and cerium with 8-hidroxiquinolina. The process of syntheses was accomplished through the methodology of co-precipitation, using as precipitant agent the 8-hidroxiquinolina. For a better control of the variables that influence the precipitation system, pH, temperature and agitation time, it was elaborated an experimental planning, similar to the static planning, having as goal the optimization of the process. It was utilized, pH: 5, 10 and 7.5; temperature: 25, 60 and 42.5 ºC; agitation periods of 1, 2 and 3 h. It was obtained co-precipitation of all the variables possible combinations, hoping to have the influence of each variable on the thermal behavior of the complexes obtained. After syntheses of the complex the same were submitted to the spectroscopy analysis on the infrared where it was established the presence of the same compounds for all the conditions. The thermal analysis was done with the goal to determinate the influence of each one of the factors of the thermal behavior of the obtained complexes. The analysis was done in an oxidative atmosphere, varying the heating rate in 5, 10 and 20 º C min. With the aid of the thermal analysis curves, it was observed that all the variables had influence in the thermal behaviors of the materials, being the pH, the variable that presented the most significant difference between the processes. To determine the phases of the oxides obtained after the thermal treatment, it was used the x-ray diffraction analysis and, by that, it was established that despite the differences in the thermal behavior of the materials, the phases obtained to all the conditions were the same, meaning, a mixture of oxide of aluminum and cerium oxide.