Banca de QUALIFICAÇÃO: TATIANE NICOLA TEJERO

THEORETICAL STUDY OF REACTIONS INVOLVING ADVANCED OXIDATIVE PROCESS IN MICROPOLUENTS PRESENT IN GANDU RIVER

Advanced oxidative process, BPA, anion sulfate radical, OH radical

Water is of great importance to human life, both for consumption and for use in the most diverse activities and, therefore, its use is indispensable. However, practices such as the disposal of domestic sewage in natura and disposal of sewage or wastewater from industrial processes make the availability of this resource, which is already finite, even smaller. These wastes that are discharged into the water may contain some substances that, even in tiny amounts, can already cause some type of damage to the environment and public health, being called micropollutants. Bearing this in mind, it is necessary both to monitor and to develop new technologies that can degrade these compounds in order to maintain the quality of water bodies. Based on work carried out on the Guandu River (this water body being of great importance for the metropolitan region of Rio and several cities in the Baixada Fluminense), it was possible to detect several micropollutants, including bisphenol A (BPA), a compound used in the manufacture of plastics and which can cause disruption of the endocrine system. A technique that has been gaining strength for the degradation of pollutants is the advanced oxidative process (AOP), in which compounds such as H2O2, sodium persulfate, ozone, among others, are used, which through exposure to heat or UV sources generate radicals with high oxidation power. AOP has been showing good results both for the treatment of pollutants in water and soil and can even be used in situ, that is, it can be applied directly in the places where the contamination occurred. In the literature there are reports of experimental work that obtained rates between 70%-97% of degradation of BPA using AOP in which the oxidative reagent was sodium persulfate. In aqueous medium and pH close to 7, the breakdown of sodium persulfate leads to the formation of sulfate anion radicals and OH radicals. The theoretical study of the reactions between BPA and the anion sulfate and OH radicals will bring a complete elucidation of this process and the kinetic description. For the elaboration of the model, three stages will be carried out: first, calculations will be carried out at a semi-empirical level, which are quick calculations and provide good inputs for the Density Functional Theory (DFT) level, which is the second stage, and finally, the inclusion of the solvent effect. These calculations will be applied both for the BPA + OH radical reaction and for the BPA + anion sulfate radical reaction, from the initial reagents to the final products and, once the model is complete, it will pass to the step of obtaining the canonical velocity coefficients that will be carried out using the program KINPRO, which was developed at the Laboratory of Chemical Kinetics at UFRRJ. The expectation is to find all the paths that make up these reactions, as well as to describe their kinetics, in order to bring to the literature unprecedented kinetic and thermodynamic parameters related to these reactions.