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Electrocatalytic dechlorination of halogenated antibiotics via synergistic effect of chlorine-cobalt bond and atomic H

Liu, Tian, Luo, Jinming, Meng, Xiaoyang, Yang, Liming, Liang, Bin, Liu, Meijun, Liu, Chengbin, Wang, Aijie, Liu, Xia, Pei, Yong, Yuan, Jili, Crittenden, John
Journal of hazardous materials 2018 v.358 pp. 294-301
antibiotics, dechlorination, electric power, electrodes, electron paramagnetic resonance spectroscopy, florfenicol, mercurous chloride, remediation, synergism
Although noble metal electrocatalysts are highly efficient in the dehalogenation of halogenated antibiotics, the prohibitive cost hinders their practical applications. In this study, a cobalt-phosphorous/oxide (CoP/O) composite prepared via a one-step electrodeposition was for the first time applied in electroreductive dechlorination of halogenated antibiotics (HA), including chloramphenicol (CAP), florfenicol (FLO) and thiamphenicol (TAP). CoP/O had a higher FLO dechlorination efficiency (91%) than Pd/C (69.3%) (t = 60 min, C0 = 20 mg L−1, applied voltage of −1.2 V vs. saturated calomel electrode (SCE)). Furthermore, the dechlorination efficiencies of CoP/O for CAP and TAP reached to 98.7 and 74.2%, respectively. The electron spin resonance and in situ Raman characterizations confirmed that atomic H* was produced via the CoP and the formation of CoCl bonds occurred on the CoO in CoP/O. The CoCl bond formation could trap HA molecules onto CoP/O and weaken the CCl bond strength. The synergistic effect of H* attack and CoCl bond was responsible for the high dechlorination efficiency. This study offers new insights into the interface mechanism of electroreductive dehalogenation process, and shows a great potential for the remediation of halogenated antibiotics contaminated wastewater.