Radiolysis of 1-naphthol in aqueous solutions

Abstract

The effects of absorbed doses, initial pH and 1-naphthol concentration onto its radiolysis in aqueous sulphuric and hydrochloric acids by gamma rays from 60Co were investigated. Under the experimental conditions, 1-naphthol degradation yields increased with increasing the absorbed doses (0.3-3.0 kGy) and with decreasing the initial 1-naphthol concentration (20-1 ppm). It was found out that the hydrated electrons did not play any significant roles in 1-naphthol radiolysis, as the degradation yields were higher at pH0 ~ 0.46 compared to those at pH0 ~ 2.0-5.0. The corresponding radiolytic yields G(-1-naphthol) were (6.13 ± 1.00)) × 10 -2 and (5.11 ± 0.22) × 10-2 μmol/J in sulphuric acids, (15.61 ± 3.85) × 10-2 and (4.76 ± 0.48) × 10-2 μmol/J in hydrochloric acids. 1-Naphthol degradation rates could be described by the kinetic equations of pseudo-first-order reactions. An empirical relation between the observed reaction constants k D and the initial 1-naphthol concentrations was established, enabling to predict the absorbed doses required for a given treatment efficiency. Three products of 1-naphthol degradation were revealed using an HPLC/UV procedure. © 2010 Akadémiai Kiadó, Budapest, Hungary.