Degradation of Metronidazole in Aqueous Solution by Electrochemical Peroxidation

Abstract

The drugs fall in a new series of water pollutants called "emergent"; such drugs are complex molecules with different physicochemical properties and biological activity, which are two characteristics that have led to their inclusion in the environment (1). The metronidazole (MTZ) is an antibiotic, widely used to treat infectious diseases caused by anaerobic bacteria and protozoa. Also, it is used in veterinary medicine as food stuff additive for poultry and fish to remove parasites (2). Administered once, the metronidazole can be excreted without undergoing transformation or metabolization, excretion through urine or feces causes the presence and accumulation of the drug in wastewaters (3)(4). The high solubility of metronidazole in water and its low biodegradability makes it a difficult contaminant to remove by traditional methods of wastewater treatment (5), causing its accumulation in the aquatic environment. Therefore various methods have been employed to remove the aqueous medium metronidazole, among them are: simultaneous application of ozonation and adsorption, adsorption / biosorption (6), coagulation, photochemical oxidation using UV-H2O2, oxidation with iron nanoparticles (7), among others. These methods showed a decrease in the concentration of metronidazole, after which the water can be treated. When using an advanced oxidation process such as electrochemical peroxidation synthetic water based on 100 ppm of a standard metronidazole, is in itself a degradation study, showing a 80.03% COD removal after 20 minutes treatment and 83.5% metronidazole concentration less at the end of treatment (60 minutes).