Sustainable waste-nitrogen upcycling enabled by low-concentration nitrate electrodialysis and high-performance ammonia electrosynthesis
Sustainable waste-nitrogen upcycling enabled by low-concentration nitrate electrodialysis and high-performance ammonia electrosynthesis
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通过低浓度硝酸盐电渗析和高性能氨电合成实现可持续的废氮升级循环
DOI：
10.1039/d3ey00058c
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Li, Wenzhen
中科院分区：
文献类型：
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作者：
Chen, Yifu;Ammari-Azar, Pouya;Liu, Hengzhou;Lee, Jungkuk;Xi, Yu;Castellano, Michael J.;Gu, Shuang;Li, Wenzhen
活性氮（Nr）是地球上生命的必需营养素，但其废物管理不善已成为我们生态系统水污染的主要问题，导致严重的富营养化和健康问题。可持续回收 Nr [如硝酸盐 (NO3−)–N] 并将其转化为氨 (NH3) 可以减轻 Nr 对环境的影响，同时减少碳密集型哈伯-博世工艺对 NH3 的需求。在这项工作中，在可扩展、多功能且经济高效的无膜碱性电解槽 (MFAEL) 中实现了高性能的 NO3−to-NH3 转化：NH3 部分电流密度高达 4.22 ± 0.25 A cm−2，法拉第效率为 84.5 ± 4.9%。 MFAEL 的独特配置允许连续生产纯 NH3 基化学品（NH3 溶液和固体 NH4HCO3），而无需额外的分离程序。综合技术经济分析 (TEA) 揭示了通过结合 MFAEL 中的 NO3− 还原和低能源成本电渗析工艺实现高效 NO3− 浓缩，从稀源升级回收废氮的经济竞争力。此外，在 MFAEL 中将 NO3− 还原与有机 Nr 化合物的氧化配对，能够将 N-O 和 C-N 键聚合转化为 NH3 作为唯一的含氮产物。这种电力驱动的工艺为区域和季节性氮积累的不断增长趋势以及对可持续氨的需求不断增加提供了经济上可行的解决方案，同时减少了碳足迹。
Reactive nitrogen (Nr) is an essential nutrient to life on earth, but its mismanagement in waste has emerged as a major problem in water pollution to our ecosystems, causing severe eutrophication and health concerns. Sustainably recovering Nr [such as nitrate (NO3−)–N] and converting it into ammonia (NH3) could mitigate the environmental impacts of Nr, while reducing the NH3 demand from the carbon-intensive Haber–Bosch process. In this work, high-performance NO3−-to-NH3 conversion was achieved in a scalable, versatile, and cost-effective membrane-free alkaline electrolyzer (MFAEL): a remarkable NH3 partial current density of 4.22 ± 0.25 A cm−2 with a faradaic efficiency of 84.5 ± 4.9%. The unique configuration of MFAEL allows for the continuous production of pure NH3-based chemicals (NH3 solution and solid NH4HCO3) without the need for additional separation procedures. A comprehensive techno-economic analysis (TEA) revealed the economic competitiveness of upcycling waste N from dilute sources by combining NO3− reduction in MFAEL and a low-energy cost electrodialysis process for efficient NO3− concentration. In addition, pairing NO3− reduction with the oxidation of organic Nr compounds in MFAEL enables the convergent transformation of N–O and C–N bonds into NH3 as the sole N-containing product. Such an electricity-driven process offers an economically viable solution to the growing trend of regional and seasonal Nr buildup and increasing demand for sustainable NH3 with a reduced carbon footprint.