Abstract: An apparatus, system and method consists of an electrolytic cell designed for simultaneous removal of total aqueous ammonia in the anolyte and production of high purity hydrogen gas in an electrolyte-free cathodic compartment. The system is designed as a divided electrochemical cell, separated by a proton exchange membrane. The cathode side is of “zero-gap-design”, where a carbon-based catalytic material is hot-pressed onto the proton exchange membrane adjacent to a cathodic current collector. Ammonia is concentrated in a high concentration brine, which flows through a conduit that is positioned in between the dividing membrane and a metal anode. The pure, high concentration brine permits operation at high current densities without the formation of fouling layers. Protons released from the oxidation of ammonia are transported across the proton exchange membrane, where hydrogen evolution proceeds in a porous, catalyst coated cathode, and facilitates the production of significant amounts of hydrogen gas.

Abstract: In a sewage treatment plant, dissolved ammonium is extracted from the waste-water stream, and is transferred to a body of secondary water. The secondary water is passed through an electrolysis station, where the ammonium is transformed to nitrogen gas. The capture and transfer can be done by ion-exchange, the electrolysis then being done on the regenerant water. Or the capture and transfer can be done by first transforming the dissolved ammonium to ammonia gas by raising the pH of the waste-water, then passing the ammonia gas through acidic secondary-water, in which the ammonia dissolves, the electrolysis then being done on the acid-water. The electrolysed, ammonium-diminished, secondary-water can be re-used in further capture/transfer episodes. The secondary-water does not mix with the waste-water stream.