Avaliação de titanatos e zirconatos de cálcio (Ca (Ti (1-x) Zrx) O3) como catalisadores para o tratamento de efluente de lavanderia e curtume por fotocatálise heterogênea

Abstract

In this work, Titanium and Zirconium oxides were evaluated as catalysts by heterogeneous photocatalysis in the treatment of effluents from the textile and tannery industries. These catalysts were characterized by Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS), Textural Analysis (BET), Photoacoustic Spectroscopy (band gap energy), X-ray Diffraction (XRD) and Zero Point of Charge (pHZPC). Factorial designs were performed and analyzing the statistical tests and the characterization results the CaTiO3 catalyst was chosen to perform the photocatalytic reactions with the real effluents. The photocatalysis assays were performed in two reactors, the first (reactor A) containing fifteen stirring points and four ultraviolet lamps (15 W each) and the second (reactor B) consisting of a reaction vessel with magnetic stirring and a mercury lamp with 125 W of potency. The efficiency of the reactions was evaluated by absorbance and COD reduction. The best results were obtained in the second reactor, which presented a percentage of absorbance removal of 87% for the textile effluent and 74% for the tannery and the reduction of COD had a percentage of 45% for the two effluents. The reactions were adjusted to the kinetic model of pseudo first order and the results obtained on reactor B presented kinetic constants of 2.07 x 10-3 (min-1) and 2.23 x 10-3 (min-1) for the reduction of COD for the laundry textile and tannery effluent, respectively. The photocatalytic treatment of effluents allowed a reduction of toxicity, evaluated by phytotoxicity tests with Lactuca sativa.