Coupling Nitrate Reduction Reaction With Ammonia Recovery: Perspectives on Principles and Engineering

Abstract

Electrochemical nitrate reduction reaction (NO₃RR) refers to the route of converting nitrate (NO₃⁻) to ammonia (NH₃). However, NH₃ dissolved in the post-reaction solution is limited for direct reuse toward downstream purposes, thereby undermining the application potentials and economic viability of NO₃RR. Instantaneous NH₃ recovery after NO₃⁻ conversion reduces the entropy of the system, thermodynamically favoring the forward reaction. NH₃ separation is necessary for both resource recovery and environmental safety considering its toxicity. Coupling NO₃RR with NH₃ recovery presents a promising solution for decentralized nitrogen management, particularly in areas with limited access to the power grid and commercial fertilizers. In this perspective, principles and engineering design of NH₃ recovery are introduced, with a highlight on heat as a suitable driving force. Looking forward, enhancing the reactant and product selectivity by smart materials design will facilitate the treatment of different nitrogen sources, and incorporating current energy infrastructures leads a way of enhancing access to electricity, sanitation and fertilizers.

Keywords

ammonia recovery / electric field / heat / membrane / nitrate reduction reaction

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2025 The Author(s). SmartMat published by Tianjin University and John Wiley & Sons Australia, Ltd.