Electrochemical reduction characteristics and mechanism of nitrobenzene compounds in the catalyzed Fe-Cu process

Article type: Research Article

Authors: XU, Wen-ying | FAN, Jin-hong | GAO, Ting-yao

Affiliations: The National Engineering Research Center for Urban Pollution Control, Tongji University, Shanghai 200092, China

Note: [] Corresponding author. E-mail: [email protected]

Abstract: The reduction of the nitrobenzene compounds (NBCs) by the catalyzed Fe-Cu process and the relationship between the electrochemical reduction characteristics of NBCs at copper electrode and reduction rate were studied in alkaline medium (pH=11). The catalyzed Fe-Cu process was found more effective on degradation of NBCs compared to Master Builder's iron. The reduction rate by the catalyzed Fe-Cu process decreased in the following order: nitrobenzene >4-chloro-nitrobenzene m-dinitrobenzene >4-nitrophenol 2,4-dinitrotoluene >2-nitrophenol. The reduction rate by Master Builder's iron decreased in the following order: m-dinitrobenzene 4-chloro-nitrobenzene >4-nitrophenol >2,4-dinitrotoluene ≈nitrobenzene >2-nitrophenol. NBCs were reduced directly on the surface of copper rather than by the hydrogen produced at cathode in the catalyzed Fe-Cu process. The reduction was realized by the hydrogen produced at cathode and Fe(OH)_2 in Master Builder's iron. It is an essential difference in reaction mechanisms between these two technologies. For this reason, the reduction by the catalyzed Fe-Cu depended greatly on NBC's electron withdrawing ability.

Keywords: wastewater contaminated by NBCs, electrochemical reduction characteristics, catalyzed Fe-Cu process, reduction mechanism

Journal: Journal of Environmental Sciences, vol. 18, no. 2, pp. 379-387, 2006