Estudo da atividade fotocatalítica das argilas contendo Al e Ce para tratamento de efluentes têxteis

Abstract

The constant use of contaminating materials, often being incorrectly disposed of in the environment, is something that has been worrying society, and "environmental preservation" is one of the most debated topics in congresses and among researchers. Thinking about this aspect of alleviating this problem, the present work has as its main focus the study of photocatalytic properties, through advanced oxidative processes (AOP), for the treatment of textile effluents. To this end, the natural and Al-pillarized clays, both impregnated with cerium, and Al/Ce mixed pillarized clays were used in the photodegradation of methylene blue dye (AZM). The materials were prepared using the traditional pilarization procedure, where materials containing: 5, 10 and 15% Ce in the pilarizing solution were produced. For the Ce impregnated samples, 5, 10 and 15% Ce was also used in the solution to impregnate the samples. All materials were calcined at 450°C. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-FEG), chemical analysis of the samples by X-ray fluorescence (XRF), textural analysis by N2 adsorption and UV-Visible spectroscopy (UV-Vis). The presence of CeO2 can be observed in all techniques, where in XRD it was possible to see the formation of CeO2 phases. It was also possible to observe the morphology of the samples, with the presence of lamellae and also with the presence of CeO2 observed by energy dispersive spectroscopy (EDS), as well as its mapping in the structure of the base material (clays). In the textural analysis made by the BET method - Brunauer, Emmett, Teller, it is possible to see that pilarization occurs in the pilarized samples because there was an increase in the specific area with a value around 239 m2 /g. Furthermore, it is possible to see that with the cerium impregnation process, there was a reduction in this specific area, which was already expected for this process. For the samples of the Campos Novos Foundation type clay (FCN) impregnated with cerium and for the commercial Bentonite clay pilarized with Al/Ce pillar it was possible to obtain the best results for photocatalytic activity, with the degradation of more than 80% of the dye used. For the other samples, the degradation did not exceed 10% of the dye.