Gamma irradiation-induced complete degradation and mineralization of phenol in aqueous solution: Effects of reagent

Abstract

This study aims to gain new insight into phenol degradation and mineralization in aqueous solution using ionizing radiation to control its radiolytic elimination under various experimental conditions and to present the different radical reactions involved in water radiolysis. The most obvious finding of this study is that the combination of a reagent, i.e., O3, H2O2, N2O, O2, or S2O82−, with γ-rays effectively enhances the radiolytic system for phenol degradation or mineralization. Radiolytic yield is higher with H2O2 than with S2O82−. For the γ-ray/free O2, γ-ray/H2O2, γ-ray/S2O82−, γ-ray/N2O, and γ-ray/N2 systems, the absorbed doses for 90% phenol elimination are 1.7, 0.85, 1.65, 1.2, and 6.4kGy, respectively; in contrast, phenol can be decomposed totally and directly via reaction with molecular ozone. The lowest dose constant for phenol removal is determined for γ-ray/HCO3−. 89% of mineralization is reached for an absorbed dose of 10kGy with a γ-ray/S2O82− combination.