Fixation of air nitrogen to ammonia and nitrate using cathodic plasma and anodic plasma in the air plasma electrolysis method

The fixation of nitrogen (N2) from the air into ammonia (NH3) and nitrate (NO3-) is usually conducted using the Haber-Bosch process, which requires the raw material of hydrocarbons for hydrogen (H2), which has a large amount of energy but produces high CO2 emissions. An environmentally friendly and energy-saving alternative is the air plasma electrolysis method, which can be used to synthesize NH3 and NO3- under ambient conditions. In this study, this method was used to inject air into the plasma zone in a K2SO4 electrolyte solution to produce N2 fixation compounds. The results showed that the use of cathodic plasma promoted the formation of NH3 but suppressed NO3- production. The optimal air injection rate was achieved at 0.6 L.min-1 and an electrical power of 452 W, with a total fixed N2 of 51.66 mmol. The highest formation of NO3- in cathodic plasma was obtained in 35 min, with a value of 29.92 mmol, and 2.57 mmol NH3 was achieved at 60 min. The high concentration of H2 gas, which is a by-product of this process, can contribute to increasing the use of Haber-Bosch green technology in the production of NH3.