  This study presents a novel and ecofriendly method for synthesizing ammonium
nitrate using activated prepared through air and ammonia plasma treatments.
Initially, PAW containing nitrate ions is produced by treating water with air
plasma. This PAW air is then frozen and exposed to low pressure NH$_3$ plasma,
introducing ammonium ions to from NH$_4$NO$_3$. We systematically investigate
the voltage current characteristics of the air and NH$_3$ plasma, analyze the
generated species and radicals to understand the mechanism of NH$_4$NO$_3$
formation, and evaluate the effects of process parameters such as NH$_3$ gas
pressure, applied voltage, and treatment time on the properties of PAW. Our
results indicate that all examined process parameters positively influence the
properties of PAW. Among these parameters, the duration of NH$_3$ plasma
treatment of PAW ice exerts the most significant effect. Specifically, the
concentration of NH4 ions increased by 134.2 percent when the NH$_3$ treatment
time was extended from 0.5 h to 1 h, compared to 12.7 and 33.3 percent
increases for NH$_3$ pressure, ranging from 0.25 to 0.55 mbar, and applied
voltage, ranging from 500 to 700 V, respectively. Similarly, variations in pH,
oxidation reduction potential, and electrical conductivity were substantially
higher with increased treatment time than with changes in gas pressure and
applied voltage. The PAW exhibited a neutral to slightly basic pH, making it
ideal for soil applications, thereby addressing the existing issue of the high
acidity of PAW and its use in agriculture.
