Avaliação da genotoxicidade e geração de subprodutos na degradação e mineralização de ciprofloxacina pelo processo UV-C/H2O2

Abstract

In this work, the UV-C/H2O2 process was optimized by a response surface methodology (RSM) for degradation and mineralization of Ciprofloxacin (CIP) in aqueous solution. The reactor operation parameters (ROP) initial hydrogen peroxide (H2O2) concentration (58.6 - 341.4 mg L-1), solution pH (3.2 - 8.8) were investigated in 600 min irradiation time. Actinometric tests showed that the suspended irradiation source (UV-C254nm) and the reflectors used in the experimental module of the UVC/H2O2 reactor presented an incident UV-C irradiation of 6.2577 x 10-9 Einstein L-1 s-1 and path length of 98.5 cm, which can be taken as basis for comparison of the process efficiency. The optimal conditions of the ROPs were initial concentration of 200 mg H2O2 L-1 and solution pH 3.2 reaching in 600 min irradiation time, presenting a CIP degradation and mineralization of 97 and 44%, respectively. Analysis Gas chromatography–mass spectrometry (GC–MS) identified the formation of intermediary byproducts, such as, phenolic antioxidants and phthalates. A genotoxicity evaluation using the bioindicator Allium cepa showed an increase in the mitotic index (MI) of the treated CIP samples in irradiation times 420 and 600 min, respectively, indicated a reduction in the toxic and cytotoxic potential of this compound in natura in the aquatic environment. At the same time the performance of antimicrobinan tests showed an inhibition of the halo diameter, contributing to the reduction of the adverse effects of this contaminant. The UV-C/H2O2 process presented good performance in decontamination of CIP in aqueous solution, being suggested as an interesting alternative for reduction of the toxic, carcinogenic and mutagenic effects caused by the inappropriate disposal of emerging contaminants (EC) in water bodies.