Easier ammonia from wastewater

Wastewater is laced with nitrates that harm ecosystems and human health. Engineers have now designed a practical reactor based on a solid electrolyte to efficiently convert those nitrates into ammonia ( Nat. Catal. 2024, DOI: 10.1038/s41929 -024-01200-w ). The Haber-Bosch process to make ammonia results in 1.3% of global CO 2 emissions . Synthesizing ammonia by renewably-powered electrochemical reduction of nitrates is a sustainable alternative. In electrochemical devices, a catalyst at the anode oxidizes water to form hydrogen ions, which go to the cathode, where another catalyst reduces nitrate to ammonia. Researchers have previously added electrolyte solutions to the reactors to boost ion conductivity, which increases ammonia generation efficiency. “But in real wastewater treatment systems, you can’t add tons of electrolyte to convert nitrate to ammonia,” says Feng-Yang Chen , a chemical and biomolecular engineer at Rice University. Chen, Haotian Wang , and colleagues designed a reactor that is split