Electrochemical degradation of nitrofurans furazolidone by cathode: Characterization, pathway and antibacterial activity analysis

Antibiotics existing in wastewaters must be degraded to eliminate its antibacterial activity before discharging into the environment. Electrochemical reduction by continuous electrons supply can degrade various refractory pollutants, however, the information about the feasibility and characterization of the cathodic degradation of nitrofurans antibiotic furazolidone (FZD) is scarce. Here, we investigated the degradation of FZD using a poised cathode electrochemical reactor. The cyclic voltammetry (CV) preliminarily proved the feasibility of FZD degradation on cathode. In contrast to the different buffer solutions concentrations, buffer types, and initial FZD concentrations which only had obvious impact on the FZD degradation efficiency, different cathode potentials had significant effects both on the FZD degradation efficiency and degradation products composition. Catholyte PBS could be replaced by Na 2 CO 3 –NaHCO 3 and NaCl buffer solution for the FZD degradation. The cathodic degradation pathway of FZD was proposed based on intermediate products analysis. When the cathode potential was lower than −0.75   V, both the furan ring and oxazole ring of FZD were destroyed to generate linear chain products after N–N bond disconnection, suggesting that the high toxic biological metabolite of FZD, 3-amino-2-oxazolidinone (AOZ) could be detoxified by cathodic degradation. This study suggests that the electrochemical reduction could serve as a potential strategy for the treatment of FZD and AOZ containing wastewater.