Remoção fotoeletrocatalítica do antibiótico ciprofloxacina usando um fotoanodo baseado em hematita modificada com materiais de bismuto

Abstract

Emerging contaminants are chemical substances or microorganisms that, although not yet widely regulated, have raised increasing concerns due to their potential environmental and public health impacts. From this perspective, this research addresses the environmental issues related to these contaminants and the risks they pose to various living organisms, highlighting the importance of developing analytical methods to investigate the degradation pathways of ciprofloxacin. The objective of this work was to synthesize nanostructured materials, characterize them and apply them in the fabrication of photoanodes for application in photoelectrocatalytic processes. The electrodes were characterized by electrochemical, morphological, structural and optical techniques. For this purpose, hematite films, bismuth-based materials and their respective composites were obtained in order to investigate their applicability in the photoelectrochemical degradation of ciprofloxacin. The optimized photoanode FTO/Fe2O3/BiOI@BiOBr was used as the working electrode in an electrochemical reactor with a volumetric capacity of 500 mL, containing ciprofloxacin at a concentration of 3.0 × 10–5 mol L–1, under constant application of a working potential of +2.0 V, with ultraviolet radiation of 9.0 W. Parameters such as pH, concentration of the supporting electrolyte, ciprofloxacin concentration, working potential and composition of the photoanode were evaluated. The photoanode revealed a degradation rate higher than 90 % and a mineralization rate of approximately 52 % after 1 hour of process. In parallel, mass spectrometry experiments revealed the formation of fourteen byproducts, allowing the proposal of a three-step degradation pathway. Therefore, the FTO/Fe2O3/BiOI@BiOBr photoanode proved to be an excellent catalytic material, presenting environmental relevance by promoting the efficient degradation of ciprofloxacin in one hour of process, with favorable energy expenditure.