Estudo de perovisquita baseada em titânio para a aplicação em fotocatálise heterogênea

Abstract

Due the advance of industrial activities and human activities,there has been a high demand for manufacturing products and among them the manufacture of pulp and paper. During the papermaking process, there is a high consumption of water and, in turn, the generation of industrial effluents, which have a high polluting charge due to the chemicals used in the course of the process. An alternative to the treatment of industrial effluents is the use of advanced oxidative processes (AOPs) and among of them the heterogeneous photocatalysis, which in turn through the semiconductor oxides action and a light source of the effluent, promotes the generation of a hydroxyl radical providing the oxidation of organic matter present in the industrial effluent reducing parameters such as chemical oxygen demand (COD) and coloration.For the present work, was sought to analyze and compare the photocatalytic action of commercial titanium dioxide (TiO2) semiconductors with two titanate perovskites being them of Calcium and Barium and determined the influence of the calcination temperature of the perovskites, and the action of a deagglomeration process in the course of the process. To evaluate the efficiency of the oxides during the photocatalytic process, realized an analysis of the pH, COD (chemical oxygen demand), effluent coloring and turbidity.The perovskites are developed through the Pechini, calcined at different temperatures of calcination, and grinding for 1 hour in a parakeet ball mill, the samples were characterized by differential thermal analysis, fluorescence of X-rays, scanning electron microscopy, diffraction of x-rays, determination of crystallite size by the Scherrer method, infrared spectroscopy and BET surface area analysis. The deagglomeration of the samples obtained satisfactory results, the samples of perovskites presented orthorhombic structures of the type, a small increase in particle size as the calcination temperature was raised, crystallite size with values between 3 and 7 nm, The perovskites presented a greater efficiency when compared with the commercial titanium dioxide in this way it becomes feasible to use them in photocatalytic processes, among the perovskites of calcium titanate that presented the highest efficiency was the calcined at 1200°C promoting a reduction of 75% of the COD, 74% of the color and 96% of turbidity of the industrial effluent, for perovskites of barium titanate that presented the highest efficiency was the calcined at 1200°C promoting a reduction of 67% of the COD, 69% of the color and 93% of turbidity of the industrial effluent.