Electrochemical removal of ammonium nitrogen in high efficiency and N2 selectivity using non-noble single-atomic iron catalyst

作者：Quan, Fengjiao; Zhan, Guangming; Zhou, Bing; Ling, Cancan; Wang, Xiaobing; Shen, Wenjuan; Li, Jianfen; Jia, Falong^*; Zhang, Lizhi^*

来源：JOURNAL OF ENVIRONMENTAL SCIENCES-CHINA, 2023, 125: 544-552.

DOI：10.1016/j.jes.2022.03.004

• Ammonia nitrogen removal
• Single-atom iron
• Non-noble metal catalyst
• Aquaculture wastewater

Ammonia nitrogen (NH4+-N) is a ubiquitous environmental pollutant, especially in offshore aquaculture systems. Electrochemical oxidation is very promising to remove NH4+-N, but suffers from the use of precious metals anodes. In this work, a robust and cheap electrocatalyst, iron single-atoms distributed in nitrogen-doped carbon (Fe-SAs/N-C), was developed for electrochemical removal of NH4+-N from in wastewater containing chloride. The Fe-SAs/N-C catalyst exhibited superior activity than that of iron nanoparticles loaded carbon (Fe-NPs/N-C), unmodified carbon and conventional Ti/IrO2-TiO2-RuO2 electrodes. And high removal efficiency (> 99%) could be achieved as well as high N-2 selectivity (99.5%) at low current density. Further experiments and density functional theory (DFT) calculations demonstrated the indispensable role of single-atom iron in the promoted generation of chloride derived species for efficient removal of NH4+-N. This study provides promising inexpensive catalysts for NH4+-N removal in aquaculture wastewater.