Change in the pH of NaI and methyl alkyl ketone solutions under gamma irradiation

Deciphering Radiolytic Oxidation in Halide Aqueous Solutions: A Pathway Toward Improved Synchrotron NAP-XPS Analysis

“…For instance, this occurs for Br – on a millisecond time scale and is likely the case for I – , given that I 3 – and Br 3 – have the highest stability constant in the X 3 – series . These species’ presence is confirmed by steady-state radiolytic studies involving doses in the range of 100 kGy. , A scheme of the reaction paths inspired by ref (blue lines) is given in Figure .…”

“…and Kim et al . These authors consider the reaction 2I – + 2HO • + 2H + → I 2(aq) + 2H 2 O, that also consumes protons, to explain why the pH of NaI solutions increases under gamma irradiation when the initial pH is <7 (note that the above reaction is a condensate of the multiple intermediary reactions leading to I 2(aq) depicted in Figure ). However, at neutral and higher pH values, the same authors consider that H 2 O 2 acts as a reducer (I 2(aq) + H 2 O 2 → 2I – + 2H + + O 2 ).…”

“…pH modifications in halide solutions under γ irradiation are reported by Jung at al. 24 and Kim et al 25 These authors consider the reaction 2I − + 2HO • + 2H + → I 2(aq) + 2H 2 O, 25 that also consumes protons, to explain why the pH of NaI solutions increases under gamma irradiation when the initial pH is <7 (note that the above reaction is a condensate of the multiple intermediary reactions leading to I 2(aq) depicted in Figure 1). However, at neutral and higher pH values, the same authors consider that H 2 O 2 acts as a reducer (I 2(aq) + H 2 O 2 → 2I − + 2H + + O 2 ).…”

“…For halide X – solutions, the XPS core-level binding energies indicate the formation of the oxidized XO – species. As this conclusion is unexpected for I – and Br – , considering prior pulse and steady-state radiolytic studies, ,,, we consider an alternative explanation, namely, the reaction of X • radicals with surface-adsorbed organic contaminants, but we do not find any substantial confirmation for it. Consequently, we discuss the conditions (such as pH) leading to the observation of hypohalites.…”

“…23 These species' presence is confirmed by steady-state radiolytic studies involving doses in the range of 100 kGy. 24,25 A scheme of the reaction paths inspired by ref 21 (blue lines) is given in Figure 1.…”