Estudo da potencialidade de aplicação da fotocatálise heterogênea na degradação de 17 α-etinilestradiol em água

Abstract

This study investigated and evaluated the efficiency of heterogeneous photo-catalysis in degrading the synthetic hormone 17α-ethinylestradiol in water. The results were obtained in three phases, using in the first two phases, tank type reactors operating in batch mode (4 hours) with an agitation system and placed in a light chamber fitted with 15-watt germicidal lamps. The catalyst used was titanium dioxide (TiO2). A 23 factorial design was used in which the factors were: percentage of catalyst (0.02% and 0.05%), initial concentration of 17αethinylestradiol (15 mg/L-1 and 30 mg / L -1) and pH (5.0 and 9.0). A prescribed methodology was used to construct a calibration curve and to determine the degradation profile of 17α-ethinylestradiol. Statistical analysis of the results was performed using the software package Minitab 15. Heterogeneous photo-catalysis with TiO proved to be an efficient process for the removal of 17α-ethinylestradiol in water with a mean removal value of 81%. Of the three factors studied in the first stage, two were statistically significant in influencing the removal efficiency of the hormone, namely the percentage of catalyst used and the initial concentration of hormone in the sample. In the second phase, the data obtained confirmed the initial results and also revealed the reaction kinetics. In the third stage, the treatment combinations were compared when using UV light and solar radiation. Removal rates for the hormone were not significantly different between the two light sources and it could be concluded that photo-catalytic degradation is a very efficient method for the removal of 17α-ethinylestradiol in water. However the system still requires optimization so as to give the best results so as to ensure the system is viable and capable of large-scale application.