High-energy ionising radiation initiated decomposition of acetovanillone

Abstract

Hydroxyl radical, hydrated electron and hydrogen atom intermediates of water radiolysis react with acetovanillone with rate coefficients of (1.05±0.1)×1010, (3.5±0.5)×109 and (1.7±0.2)×1010mol−1dm3s−1. Hydroxyl radical and hydrogen atom attach to the ring forming cyclohexadienyl type radicals. The hydroxyl–cyclohexadienyl radical formed in hydroxyl radical reaction in dissolved oxygen free solution partly transforms to phenoxyl radical. In the presence of O2 phenoxyl radical formation and ring destruction are observed. Hydrated electron in O2 free solution attaches to the carbonyl oxygen and undergoes protonation yielding benzyl type radical. In air saturated 0.5mmoldm−3 solution using 15kGy dose most part of acetovanillone is degraded, for complete mineralisation five times higher dose is required. The experiments clearly show that acetovanillone can be efficiently removed from water by applying irradiation technology.