Institut des Sciences Chimiques de Rennes, Université de Rennes 1, UMR-CNRS 6226, Campus de Beaulieu, 35042 Rennes Cedex, France; Laboratoire de recherche de Catalyse d'Electrochimie de Nanomatériaux et leurs applications et de didactique CENAD, Institut National des Sciences Appliquées et de Technologie (INSAT), B.P.N°676, 1080 Tunis Cedex, Tunisia; Université Européenne de Bretagne, 35000, France.
Institut des Sciences Chimiques de Rennes, Université de Rennes 1, UMR-CNRS 6226, Campus de Beaulieu, 35042 Rennes Cedex, France; Institut des Sciences Chimiques de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, UMR-CNRS 6226, Avenue du Général Leclerc, CS 50837, 35042 Renne Cedex 7, France; Université Européenne de Bretagne, 35000, France.
J Hazard Mater. 2014 Aug 15;278:172-9. doi: 10.1016/j.jhazmat.2014.06.003. Epub 2014 Jun 10.
The removal of metronidazole, a biorecalcitrant antibiotic, by coupling an electrochemical reduction with a biological treatment was examined. Electroreduction was performed in a home-made flow cell at -1.2V/SCE on graphite felt. After only one pass through the cell, analysis of the electrolyzed solution showed a total degradation of metronidazole. The biodegradability estimated from the BOD5/COD ratio increased from 0.07 to 0.2, namely below the value usually considered as the limit of biodegradability (0.4). In order to improve these results, indirect electrolysis of metronidazole was performed with a titanium complex known to reduce selectively nitro compounds into amine. The catalytic activity of the titanium complex towards electroreduction of metronidazole was shown by cyclic voltammetry analyses. Indirect electrolysis led to an improvement of the biodegradability from 0.07 to 0.42. To confirm the interest of indirect electroreduction to improve the electrochemical pretreatment, biological treatment was then carried out on activated sludge after direct and indirect electrolyses; different parameters were followed during the culture such as pH, TOC and metronidazole concentration. Both electrochemical processes led to a more efficient biodegradation of metronidazole compared with the single biological treatment, leading to an overall mineralization yield for the coupling process of 85%.
考察了通过电化学还原与生物处理相结合来去除生物难降解抗生素甲硝唑。在自制的流动池中，石墨毡在-1.2V/SCE 下进行电还原。仅通过一次通过电池，对电解溶液的分析表明甲硝唑已完全降解。从 BOD5/COD 比估算的生物降解性从 0.07 增加到 0.2，即低于通常认为的生物降解性极限（0.4）。为了提高这些结果，用已知可选择性地将硝基化合物还原为胺的钛配合物进行间接电解甲硝唑。通过循环伏安分析表明钛配合物对甲硝唑电还原的催化活性。间接电解将生物降解性从 0.07 提高到 0.42。为了确认间接电解在改善电化学预处理方面的优势，然后在直接和间接电解后在活性污泥上进行生物处理；在培养过程中跟踪了不同的参数，如 pH、TOC 和甲硝唑浓度。与单一生物处理相比，这两种电化学过程都使甲硝唑的生物降解更有效，耦合过程的总矿化率达到 85%。
