Radiation oxidation of phenol in the presence of petrochemical wastewater components

Abstract

Radiolytical decomposition of phenol was investigated at⁶⁰Co gamma irradiation (1–2 Gy·s⁻¹, ≤10 kGy) of pre- and continuously aerated aqueous solutions at concentrations of phenol 1–100 mg· ·dm⁻³ and in the presence of sodium hydroxide, sulphuric acid, sodium and ferrous sulphate, formaldehyde, 2-propanol,n-hexane, xylene, benzene, and commercial gasoline. From the decomposition rate at doses 50–400 Gy, a phenomenological model of linear relation between the dose acquired for 37% decomposition (D ₃₇), initial concentration (g·m⁻³) of phenol (p ₀) and of an admixture (s ₀) was confirmed in the formD ₃₇=52f _tr(p ₀+f _eq s ₀), wheref's are constants which can be attributed to the relative transformation resistance of phenol towards the OH radicals in given matrix (f _tr, for pure waterf _tr=1) and relative acceptor capacity of competing substrate (f _eq). In real wastewaters, the efficient decrease of phenols content may be substantially lower than that in model solutions, obviously due to radiation oxidation of aromates, as proved by irradiation of aqueous solutions of benzene. Technical and economical feasibility of the process is discussed.