Preparação e caracterização de composições binarias de TiO2 e FeOX empregados como catalisadores em processos oxidativos avançados

Abstract

Due to increased environmental awareness, several methodologies are being studied in the quest to minimize the effect caused by the improper disposal of effluents. The treatment of these effluents is a major technological challenge, because many times, the conventional treatment technologies are not efficient to tailor it to disposal. The goal of this work is to develop new heterogeneous catalysts for the Fenton reaction, immobilized on a matrix of TiO2, with a view to application in wastewater treatment. The catalysts FeOx and TiO2 were deposited on a Ti plate through thermal decomposition, the compositions were prepared in the following ratios: 100 % FeOx; 90 % FeOx : 10 % TiO2; 70 % FeOx: 30 % TiO2; 50 % FeOx : 50 % TiO2; 30 % FeOx : 70 % TiO2; e 10% FeOx : 90% TiO2. The efficiency of the catalysts was tested in the treatment of a synthetic wastewater containing the sun yellow dye, in the absence and presence of radiation. In the absence of radiation showed a slight efficiency of the heterogeneous Fenton reaction in the reduction of dye concentration, while in the presence of radiation, there was a significant increase in the rate of oxidation dye, especially for catalysts with a low proportion of iron and the composition containing iron 100%. The greater efficiency of the photo system was associated the many processes occurring simultaneously: Photolysis - H2O2 / UV; Heterogeneous Fenton Reaction - H2O2 + Fe2+; Heterogeneous PhotoFenton Reaction - (H2O2 + Fe2+) / UV; and Photocatalysis - TiO2 / UV. Evaluating the processes the following sequence of catalytic activity for the degradation of the dye was observed: TiO2-FeOx/H2O2/UV > H2O2/UV >> TiO2-FeOx/H2O2.