Effect of denitrifying bacteria on the electrochemical reaction of activated carbon fiber in electrochemical biofilm system
Tóm tắt
An electrochemical-activated denitrifying biofilm system consisting of activated carbon fiber electrodes immobilized with denitrifying bacteria film as cathode was studied. A revised model for an electrochemical-activated denitrifying biofilm was developed and validated by electrochemical analysis of cathodal polarization curves and nitrate consumption rate. The cathodal polarization curve and nitrate consumption rate were introduced to verify the rate of electrochemical reaction and the activity of denitrifying bacteria, respectively. It was shown that the denitrification process effectively strengthened the electrochemical reaction while the electron also intensified denitrification activity. Electron was transferred between electrochemical process and biological process not only by hydrogen molecule but also by new produced active hydrogen atom. Additionally, a parameter of apparent exchange current density was deprived from the cathodal polarization curve with high overpotential, and a new bio-effect current density was defined through statistical analysis, which was linearly dependent to the activity of denitrification bacteria. Activated carbon fiber (ACF) electrode was also found to be more suitable to the electrochemical denitrifying system compared with graphite and platinum.
Tài liệu tham khảo
Dahab M F, Lee Y W. Nitrate removal from water supplies using biological denitrification. J WPCF, 1988, 60: 1670–1677
Fan B, Qu J H, Lei P J, Li D P. Studies on nitrate removal by a combined heterotrphy-electrode-biofilm reactor. ACTA Scientiae Circumstantiae, 2001, 21(3): 257–262 (in Chinese)
Zhang Y, Chen Y X, Chen G H. Chemical denitrification of nitrate from groundwater. Environmental Science, 2003, 24(4): 109–113 (in Chinese)
Zhang L H, Jia J P, Zhu Y C, Zhu N W, Wang Y L, Yang J. Electrochemically improved bio-degradation of municipal sewage. Biochemical Engineering Journal, 2005, 22(3): 239–244 (in Chinese)
Kurt M, Dunn I J, Bourne J R. Biological denitrification of drinking water using autotrophic organism with H2 in a fluid-bed biofilm reactor. Biotechnol Bioeng, 1987, 29(4): 493–501
Mellor R B, Ronnenberg J, Campbell W H, Diekmann S. Reduction of nitrate and nitrite in water by immobilized enzymes. Nature, 1992, 20(2): 355–367
Sakakibara Y, Nakayama T. A novel multi-electrode system for electrolytic and biological water treatment: Electric charge transfer and application to denitrification. Water Research, 2001, 35(3): 768–773
Sakakibara Y, Kuroda K. Electric prompting and control of denitrification. Biotechnol Bioeng, 1993, 42(4): 535–537
Sakakibara Y, Araki K, Tankaka T, Watanabe T, Kuroda M. Denitrification and neutralization with an electrochemical and biological reactor. Water Sci Technol, 1994, 30(6): 151–155
Huang M S, Gao T Y. Denitrification with a cathod biofilm reactor. Shanghai Environmental Science, 1996, 15(6): 25–27 (in Chinese)
Cao G M, Zhao Q X, Sun X B, Zhang T. Studies on the preparation of immobilized-cell membrane and its characteristics. China Environmental Science, 2001, 21: 207–211 (in Chinese)
State Environmental Protection Administration (SEPA). Water and Wastewater Analytical Methods. Beijing: China Environmental Science Press, 1997, 260–266 (in Chinese)
Frankenthal R P, Milner P C. Hydrogen evolution kinetics on a high-carbon steel and on tin in seawater. Corrosion, 1986, 42(1): 51–53
Gennero de Chialvo M R, Chialvo A C. Analysis of an unusual behavior of the hydrogen evolution reaction: Two Tafelian regions with equal slope. International Journal of Hydrogen Energy, 2002, 27: 871–877
Sakakibara Y, Flora J R V, Suidan M T, Kurodo M. Modeling of electrochemically-activated denitrifying biofilms. Water Research, 1993, 28(5): 1077–1086