title: Cathodic degradation of antibiotics: characterization and pathway analysis.
abstract: Antibiotics in wastewaters must be degraded to eliminate their antibacterial activity before discharging into the environment. A cathode can provide continuous electrons for the degradation of refractory pollutants, however the cathodic degradation feasibility, efficiency and pathway for different kinds of antibiotics is poorly understood. Here, we investigated the degradation of four antibiotics, namely nitrofurazone (NFZ), metronidazole (MNZ), chloramphenicol (CAP), and florfenicol (FLO) by a poised cathode in a dual chamber electrochemical reactor. The cyclic voltammetry preliminarily proved the feasibility of the cathodic degradation of these antibiotics. The cathodic reducibility of these antibiotics followed the order of NFZ > MNZ > CAP > FLO. A decreased phosphate buffered solution (PBS) concentration as low as 2 mM or utilization of NaCl buffer solution as catholyte had significant influence on antibiotics degradation rate and efficiency for CAP and FLO but not for NFZ and MNZ. PBS could be replaced by Na2CO3-NaHCO3 buffer solution as catholyte for the degradation of these antibiotics. Reductive dechlorination of CAP proceeded only after the reduction of the nitro group to aromatic amine. The composition of the degradation products depended on the cathode potential except for MNZ. The cathodic degradation process could eliminate the antibacterial activity of these antibiotics. The current study suggests that the electrochemical reduction could serve as a potential pretreatment or advanced treatment unit for the treatment of antibiotics containing wastewaters.
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors: Deyong
authors: D
authors: Kong
authors: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
authors: Bin
authors: B
authors: Liang
authors: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
authors: Hui
authors: H
authors: Yun
authors: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
authors: Haoyi
authors: H
authors: Cheng
authors: College of Environment and Resources, Jilin University, Changchun 130021, PR China.
authors: Jincai
authors: J
authors: Ma
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors: Minhua
authors: M
authors: Cui
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China. Electronic address: waj0578@hit.edu.cn.
authors: Aijie
authors: A
authors: Wang
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China. Electronic address: rnq@hit.edu.cn.
authors: Nanqi
authors: N
authors: Ren
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D002021:Buffers; D002701:Chloramphenicol / Q000737:chemistry / Q000494:pharmacology; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D013294:Lactococcus lactis / Q000187:drug effects / Q000254:growth & development; D013058:Mass Spectrometry; D008795:Metronidazole / Q000737:chemistry / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009583:Nitrofurazone / Q000737:chemistry; D012996:Solutions; D013839:Thiamphenicol / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D018675:Toxicity Tests
chemical_list: D000900:Anti-Bacterial Agents; D002021:Buffers; D012996:Solutions; D008795:Metronidazole; D002701:Chloramphenicol; C035534:florfenicol; D013839:Thiamphenicol; D009583:Nitrofurazone
keywords: Antibacterial activity elimination; Antibiotics degradation; Cathode potential; Dehalogenation; Nitro group reduction