Radiolysis of 1-naphthol in aqueous solutions

The effects of absorbed doses, initial pH and 1-naphthol concentration onto its radiolysis in aqueous sulphuric and hydrochloric acids by gamma rays from Co-60 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 pH(0) similar to 0.46 compared to those at pH(0) similar to 2.0-5.0. The corresponding radiolytic yields G(-1-naphthol) were (6.13 +/- A 1.00)) x 10(-2) and (5.11 +/- A 0.22) x 10(-2) mu mol/J in sulphuric acids, (15.61 +/- A 3.85) x 10(-2) and (4.76 +/- A 0.48) x 10(-2) mu mol/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.