Alpha radiolysis of nitric acid and sodium nitrate with 4He2+ beam of 13.5 MeV energy

• G(H2O2) decreases linearly with increasing nitrate ion concentrations.
• G(H2O2) increases considerably with increasing acidity (up to [H+]=0.5 mol L−1).
• G(HNO2) increases with increasing nitrate and hydronium concentrations until a plateau is reached.
• The effects of nitrate and hydronium ions on G(H2O2) and G(HNO2) are additive.

A study of aqueous nitric acid solution alpha radiolysis was performed through experiments carried out at a cyclotron facility, where a helion beam with an energy of 13.5 MeV could be delivered into the solution. The effects of nitrate and hydronium ions on the formation yields of hydrogen peroxide and nitrous acid, G(H2O2) and G(HNO2), were studied. The results showed that G(H2O2) decreases linearly with increasing nitrate ion concentration. On the other hand, G(HNO2) increases with the nitrate ion concentration until it reaches a plateau for nitric acid concentrations higher than 2 mol L–1. It was also found that an increase of hydronium ion concentration has a favorable effect on G(H2O2) and G(HNO2). Furthermore, it appears that these effects are additive and that the variations of G(H2O2) and G(HNO2) can be described by two parametric expressions, as a function of the nitrate and hydronium ion concentrations.