Nitrogen Fixation Into Water by Pulsed High-Voltage Discharge

Nitrogen in the bubbling gas was directly fixed into water by pulsed high-voltage discharge. When the discharge occurred, nitrogen could be dissociated to form active N species to take part in the aqueous chemical process. Nitrous acid (HNO 2 ) was primarily produced, which was further converted into nitric acid (HNO 3 ). With the formation of HNO 2 and HNO 3 , the pH of the liquid decreased. The decrease in pH sped up the conversion from HNO 2 into HNO 3 , thus resulted in an increase in the NO 2 - concentration at first and a decrease after a turning point. The nitrogen fixation rate with bubbling nitrogen was faster than that with bubbling air in distilled water. By discharge for about 30 min, HNO 2 was converted into HNO 3 as the final products. Its concentrations were 1.96 mmol . L -1 with bubbling air and 2.34 mmol . L -1 with bubbling pure nitrogen. The energy efficiencies were 2.08 times 10 -9 and 2.48 times 10 -9 mol . J -1 , respectively.