Author(s)

Yaning Wang, Xu Guo, Jinglu Li, Yingnan Yang, Zhongfang Lei, Zhenya Zhang

Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.

Electrochemical oxidation of ammonia was studied with an objective to enhance the selectivity of ammonia to nitrogen gas and to remove the by-products in an undivided electrochemical cell, in which various cathodes and Ti/RuO ₂-Pt anode were assembled. In the present study, anodic oxidation of ammonia and cathodic reduction of by-products were achieved, especially with Cu/Zn as cathode. In the presence of 1.0 g/L NaCl the ammonia-N decreased from 100.0 to 0 after 120 min electrolysis at current density of 30 mA/cm², and no nitrite was detected in the treated solution. The lowest amount of nitrate was formed with Cu/Zn as cathode during electrolysis due to its high reduction ability. Initial pH range from 7 and 9 and uncontrolled temperature were favorable for electrochemical ammonia oxidation and the ammonia oxidation rates with Cu/Zn cathode was higher than that with Ti and Fe cathode. The reduction rate increased with increasing current density in the range of 5 - 50 mA/cm². As ammonia could be completely removed by the simultaneous oxidation and reduction in this study, it is suitable for deep treatment of ammonia polluted water.

Electrochemical Oxidation; Ammonia; Nitrate; Cu/Zn; Sodium Chloride

Y. Wang, X. Guo, J. Li, Y. Yang, Z. Lei and Z. Zhang, "Efficient Electrochemical Removal of Ammonia with Various Cathodes and Ti/RuO₂-Pt Anode," Open Journal of Applied Sciences, Vol. 2 No. 4, 2012, pp. 241-247. doi: 10.4236/ojapps.2012.24036.