Amateur synthesis of sodium nitrate and sodium nitrite by electrolytic oxidation of ammonia in a diaphragm separated cell

In this report we describe the electrolytic oxidation of ammonia as published by Traube and Biltz in 1904, utilizing an easy to produce electrolytic cell with a terracotta flowerpot as the ion exchange membrane. We further show the synergy of the iron anode and copper catalyst by demonstrating the enhanced reactivity of sodium ferrate with ammonia in the presence of copper(II) under cell conditions. Overall, high current efficiencies for the synthesis of nitrite were obtained with relatively low current densities, even from a simple cell design. Regardless of cell conditions, electrolysis always seems to produce a mixture of mostly nitrite and some nitrate. Due to anode wear and low current efficiencies, the further electrolytic conversion of nitrite to nitrate proved impractical. Instead, this report describes a simple method for conversion of the sodium nitrite obtained to relatively pure sodium nitrate by air-mediated-oxidation of aqueous sodium nitrite at a pH of 3. We also describe the removal of nitrate from the electrolysis products obtained by high temperature reduction of nitrate with copper powder, thereby allowing the synthesis of pure sodium nitrite from the electrolytic oxidation of ammonia.