Projeto e avaliação de um reator eletroquímico para o processo oxidativo avançado de fármacos presentes em efluentes domésticos.

Abstract

The concern with the presence of pharmaceuticals in the aquatic environment stems from their chemical persistence, microbial resistance, and synergistic effects that lead to toxicological implications. Electrochemical technology appears as an alternative to the conventional treatment of pharmaceutical effluents as it offers an efficient means of removing or destroying polluting species. Hydrogen peroxide (H2O2) is a powerful oxidant that has been applied in the treatment of industrial wastewater and, therefore, the study of electrochemical reactors to produce hydrogen peroxide has generated great interest in the scientific community. In this context, this project aimed to design, build, evaluate and model an electrochemical reactor with a flow-by configuration to be applied in the advanced oxidative process (AOP) of the drug ciprofloxacin, through the in situ production of the oxidizing agent - peroxide. hydrogen, using carbon felt as the cathode. Therefore, the project of the electrochemical reactor was carried out and the mass transfer study was carried out from the determination of the reduction current of the ferricyanide ion associated with the amperometric titration method. In addition, the study of the experimental parameters that influence the production of H2O2 from the preparation of the modified carbon paste electrode (CPE-Pd), the determination of oxygen saturation from the measurement of dissolved oxygen (DO) was carried out. Finally, H2O2 production tests were carried out in the electrochemical cell. The results of the modeling of the reactor indicated the presence of different fluid dynamic conditions, being obtained two empirical models for the studied electrochemical cell. Also, it was possible to observe the peak absorbance of ciprofloxacin at 275 nm and it was possible to obtain the calibration curve of the antibiotic. The scanning voltammetry (LSV) technique using CPE-Pd proved to be efficient in identifying H2O2, but it was not possible to observe its formation in the electrochemical cell. Finally, it is recommended to improve the oxygen delivery system to improve its diffusion into the electrolyte solution of the cell and to apply some activation technique to the carbon electrode in order to obtain the hydrogen peroxide production reaction.