Abstract
The mechanism for catalytic wet air oxidation (CWAO) of ammonia to N2 over Ru–Cu/C catalyst is extensively studied by altering the initial pH, reaction temperature and atmosphere. It is found that N2 formation can be from the catalytically selective oxidation of ammonia or the disproportionation reaction between NH4+ and NO2−. The initial oxidation of ammonia determines the reaction mechanism, the evolution of pH and the distribution of various nitrogen species. Over-oxidation to nitrous acid lowers the pH of the solution due to dissociation of HNO2 to H+ and NO2−. With the decrease of pH, the concentration of NH4+ is increased and rapidly reacts with NO2− to form N2. The relatively lower pH also makes some nitrites be oxidized to NO3−. Enhancing the reaction of selective oxidation of ammonia to N2 increases the selectivity to N2 while limits the pH decrease and NO3− formation, since NO2− is more dominant to HNO2 at high pH and hardly oxidized to NO3−. The reaction temperature is one key factor to determine the reaction mechanism of CWAO of ammonia.
Graphical Abstarct
Similar content being viewed by others
References
Verstraete W, Philips S (1998) Environ Pollut 102:717–726
Dongen van U, Jetten M, Van Loosdrecht M (2001) Water Sci Technol 44:153–160
Huang TL, MacInnes JM, Cliffe KR (2001) Water Res 35:2113–2120
Chen JP, Chua ML, Zhang B (2002) Waste Manag 22:711–719
Rožić M, Cerjan-Stefanović Š, Kurajica S, Vančina V, Hodžić E (2000) Water Res 34:3675–3681
Radnik J, Benhmid A, Kalevaru VN, Pohl MM, Martin A, Lücke B, Dingerdissen U (2005) Angew Chem Int Ed 44:6771–6774
Taguchi J, Okuhara T (2000) Appl Catal A 194–195:89–97
Bernardi M, Le DM, Dodouche I, Descorme C, Deleris S, Blanchet E, Besson M (2012) Appl Catal B 128:64–71
Cao SL, Chen GH, Hu XJ, Yue PL (2003) Catal Today 88:37–47
Lousteau C, Besson M, Descorme C (2015) Catal Today 241:80–85
Li Y, Zhang R, Li HS, Dong M (2005) Chem J Chin 26:430–435
Takayama H, Qin JY, Inazu K, Aika K (1999) Chem. Lett 28:377–378
Hung CM, Lou JC, Lin CH (2003) Chemosphere 52:989–995
Hung CM (2009) Environ Eng Sci 26:351–358
Hung CM (2009) J Hazard Mater 166:1314–1320
Hung CM (2009) J Hazard Mater 163:180–186
Kaewpuang NS, Inazu K, Kobayashi T, Aika KI (2004) Water Res 38:778–782
Qin J, Aika K (1998) Appl Catal B 16:261–268
Webley PA, Tester JW, Holgate HR (1991) Ind Eng Chem Res 30:1745–1754
Barbier JJ, Oliviero L, Renard B, Duprez D (2002) Catal Today 75:29–34
Lee DK (2003) Environ Sci Technol 37:5745–5749
Lee DK, Cho JS, Yoon WL (2005) Chemosphere 61:573–578
Fu J, Yang K, Ma C, Zhang N, Gai H, Zheng J, Chen BH (2016) Appl Catal B 184:216–222
Wang Z, Hameed S, Wen Y, Zhang N, Gai H, Zheng J, Chen BH (2017) Sci Rep 7:3911
Acknowledgements
The authors would like to thank the financial supports from the National Key Technology Support Program of China (2014BAC10B01). Prof Dr Gai would like to thank the support from key scientific and technological project of China’s Shanxi Province (MH2014-10). The support by the Natural Science Foundation of Fujian Province of China (2015J05031) and the Natural Science Foundation of China (21673187) are also acknowledged.
Author information
Authors and Affiliations
Corresponding authors
Rights and permissions
About this article
Cite this article
Fu, J., Xiao, D., Yue, Q. et al. Insights into the Reaction Mechanism of Catalytic Wet Air Oxidation of Ammonia Over Bimetallic Ru–Cu Catalyst. Top Catal 61, 1684–1693 (2018). https://doi.org/10.1007/s11244-018-1019-x
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11244-018-1019-x