Radiolysis of Dilute Aerated Sulfuric Acid Solutions with 5.3-MeV Alpha Particles

Abstract

The hydrogen peroxide yield in aerated sulfuric acid solutions, irradiated with 5.3-MeV α-particles, has been measured as a function of the acid concentration in the range from $5\times 10^{-3} M$ to 1 M H2 SO4. It was found that the curve $G({\rm H}_{2}{\rm O}_{2})$ versus [ H2 SO4] presents a maximum, $G({\rm HO}_{2})=1.56$, for $[{\rm H}_{2}{\rm SO}_{4}]=5\times 10^{2} M$. From comparison of this curve with that obtained with similar solutions containing 10-4 M KBr, it was concluded that sulfuric acid interferes both with reactions taking place in the bulk of the solution (by scavenging of OH radicals) and with intratrack phenomena (through reaction between $e_{{\rm aq}}^{-}$ and H3 O+ ions). The results indicate that the formation of sulfate radicals is repressed by some mechanism. For the interpretation of these results the existence of some such reaction as ${\rm SO}_{4}^{-}{}^{-}+{\rm OH}+{\rm H}^{+}\rightleftarrows {\rm SO}_{4}{}^{-}+{\rm H}_{2}{\rm O}$ is considered.