Nitrate as an Oxidant in the Cathode Chamber of a Microbial Fuel Cell for Both Power Generation and Nutrient Removal Purposes
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Nitrate ions were used as the oxidant in the cathode chamber of a microbial fuel cell (MFC) to generate electricity from organic compounds with simultaneous nitrate removal. The MFC using nitrate as oxidant could generate a voltage of 111 mV (1,000 Ω) with a plain carbon cathode. The maximum power density achieved was 7.2 mW m−2 with a 470 Ω resistor. Nitrate was reduced from an initial concentration of 49 to 25 mg (NO 3 − −N) L−1 during 42-day operation. The daily removal rate was 0.57 mg (NO 3 − –N) L−1 day−1 with a voltage generation of 96 mV. In the presence of Pt catalyst dispersed on cathode, the cell voltage was significantly increased up to 450 mV and the power density was 117.7 mW m−2, which was 16 times higher than the value without Pt catalyst. Significant nitrate removal was also observed with a daily removal rate of 2 mg (NO 3 − –N) L−1 day−1, which was 3.5 times higher compared with the operation without catalyst. Nitrate was reduced to nitrite and ammonia in the liquid phase at a ratio of 0.6% and 51.8% of the total nitrate amount. These results suggest that nitrate can be successfully used as an oxidant for power generation without aeration and also nitrate removal from water in MFC. However, control of the process would be needed to reduce nitrate to only nitrogen gas, and avoid further reduction to ammonia.
KeywordsNitrate removal Microbial fuel cell Power generation Cathode chamber Electron acceptor
The authors thank Óscar Benito Román; and also thank Hector Garcia for his help with analytical measurements. This research was supported by Danish Agency for Science Technology and Innovation, 2104-05-0003. This work was also supported by the Ph.D. scholarship from the Department of Environmental Engineering, Technical University of Denmark.
- 1.Hallberg, G. R. (1989). Nitrate in ground water in the United States. In R. F. Follet (Ed.), Nitrogen management and ground water protection (pp. 35–74). Amsterdam: Elsevier.Google Scholar
- 2.Puckett LJ (1995). Identifying the major sources of nutrient water pollution. Environmental Science & Technology, 29(9), 408A–414A.Google Scholar
- 3.Freshwater in Europe-Facts, Figures and Maps. Division of Early Warning and Assessment, Office for Europe (DEWA ∼ Europe), United Nations Environment Programme (UNEP). Available from: http://www.grid.unep.ch/product/publication/freshwater_europe.php. Accessed January 05, 2010.
- 5.Canter, L. W. (1997). Nitrates in groundwater. Boca Raton: CRC Press.Google Scholar
- 9.NLM, RTECS (Registry of Toxic Effects of Chemical Substances), Bethesda, MD, Record No. 36474, 1999.Google Scholar
- 18.American Public Health Association, American Water Works Association, Water Pollution Control Federation. (1995). Standard methods for the examination of water and wastewater (19th ed.). Washington, DC: American Public Health Association.Google Scholar
- 19.EPA method 353.2, nitrogen, nitrate-nitrite (colorimetric, automated, cadmium reduction)Google Scholar