Abstract: The electrochemical reduction of nitrates in aqueous solutions thereof in the presence of amides to gaseous nitrogen (N2) is described. Generally, electrochemical reduction of NO3 proceeds stepwise, from NO3 to N2, and subsequently in several consecutive steps to ammonia (NH3) as a final product. Addition of at least one amide to the solution being electrolyzed suppresses ammonia generation, since suitable amides react with NO2 to generate N2. This permits nitrate reduction to gaseous nitrogen to proceed by electrolysis. Suitable amides include urea, sulfamic acid, formamide, and acetamide.

Abstract: Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.