Photodegradation of Enrofloxacin by the Photo-Fenton-Like Reaction Using UVA-Irradiated Iron(III)-Tartrate as a Source of Iron(II)

Abstract

The consumption of veterinary drugs has grown over the past decades as a consequence of the increasing global demand for food. However, the nonmetabolized fraction of these drugs ends up in the environment through animal excretion, with substantial adverse effects on the environment. Therefore, novel and effective water and wastewater treatment techniques capable of eliminating these pollutants are urgently needed. To this end, advanced oxidation processes (AOPs) are promising alternatives for this purpose. Fenton reactions are among the most studied AOPs, although they present some practical restrictions due to iron low solubility at environmental pH. Thus, the use of irradiated Fe(III)-carboxylates emerges as a possible solution to overcome this drawback. The aim of this study is to investigate the possibility of using UVA-irradiated Fe(III)-tartrate complex as a source of Fe(II) in a photo-Fenton-like reaction, for degrading the veterinary drug enrofloxacin (ENR). ENR removal was studied for different Fe(III) to tartrate proportions and pH, which were varied according to a Doehlert experimental design. Results indicate that higher tartrate concentrations enable the pH extension up to neutral, which potentiates the application of the studied process in real water matrices. Moreover, antimicrobial assays with Vibrio fischeri and Lacto bacillus, performed with untreated and treated ENR solutions, showed that antibiotic removal does not necessarily lead to toxicity removal. Further investigation is thus required to correlate the toxicity results to ENR degradation products.