Degradação da ciclofosfamida em meio à urina artificial por processos eletroquímicos oxidativos avançados

Abstract

The growing demand for personal care products and pharmaceuticals has increased considerably, causing great concern for the environment and public health. Drugs such as cyclophosphamide, are excreted unchanged, or as active metabolites, in urine, reaching sewage treatment systems. Because they are present at low concentrations (μg L-1 to ng L-1), such substances are not completely removed and are resistant to biodegradation. The objective of this work was to study the degradation of the antineoplastic cyclophosphamide in artificial urine medium, which presents high concentrations of various ions, by Electrochemical Advanced Oxidation Processes (EAOP). The system consisted of an electrochemical flow reactor with a commercial DSA® electrode (nominal composition Ti/Ru0,3Ti0,7O2) and Ti-mesh cathode. In order to assess the best parameters, the effect of current, time and flow rate were analyzed using an initial factorial 23 factorial design. The chosen response variable was the energy efficiency for the production of free chlorine species (HClO/ClO-). After obtaining the most significant factors, the Central Composite Design (CCD) was performed, where the optimum conditions were determined for the current range (0,164 A and 0,932 A), flow rate (7,022 mLmin-1) and time range (19 and 37 min). Under an optimized condition, the efficiency of other combined methods (photo-assisted electrochemical, photochemical, sonoelectrochemical and photo assisted sonoelectrochemical) was evaluated. The efficiency of degradation processes was determined by removal of Chemical Oxygen Demand (COD), creatinine and urea. Analysis by HPLC demonstrates that the cyclophosphamide was substantially removed during the treatment process of ~77%. Based on these results, it can be observed that the coupling between electrochemical and photochemical processes is a promising alternative for the treatment of this effluent, as a marked reduction of organic matter is observed (63, 94% of creatinine, 29, 62% of urea, 39, 1% of TOC) and a low treatment cost ratio. Evidence that the techniques studied present better.