Óxido misto Fe2O3/SiO2 como suporte catalítico para o processo like-Fenton na degradação de corantes reativos

Abstract

Effluents from the textile industry, characterized by the use of reactive dyes, are major sources of environmental contamination. Due the nature non-biodegradable and high resistance to conventional treatments, new technologies have been studied. The photo-Fenton process as one of the POA, has excelled in remediation of dyes due the efficiency in the generation of hydroxyl radicals. Whereas that, process is catalyzed by ferric ions, the narrow pH range of study becomes a limitation. In an attempt to minimize this problem we chose to use immobilized forms of iron and used as an alternative: mixed oxide Fe2O3-SiO2. This was obtained by the sol-gel method via alkoxide precursor (TEOS), using two different routes of catalyst, and acidic and another basic. The material was characterized by infrared spectroscopy and Raman spectroscopy, ultraviolet-visible, X-ray diffraction and scanning electron microscopy, thermogravimetric analysis TG/DTA. The results of kinetic studies showed good catalytic efficiency of the mixed oxide in like-Fenton process, when they were observed degradation of a mixture of dyes in the order of 82% in 70 minutes of reaction. In alkaline solution of dyes, we observed a reduction in the absorbance of chromophore group of about 50% in 120 minutes of reaction, showing that the immobilization of the catalyst allowed a greater range of pH, thus satisfying with this purpose.