Oxidation of phenolic compounds by ozone and ozone + u.v. radiation: A comparative study

Abstract

This study was designed to investigate the reaction mechanisms of oxidation of various phenolic compounds by ozone and ozone + u.v. radiation at pH 2.5, 7.0 and 9.0. Experimental results indicated that the molecular ozone is the predominant oxidant only at acidic pH; at neutral and basic pH, in the absence or presence of u.v. radiation, free radical reaction is the major pathway in the oxidation of phenolic compounds. The overall removal of phenols and the removal of TOC increase with increasing pH during ozonation with or without u.v. light. For a specific pH, the removal rates of phenol and TOC are highest for ozone + u.v. light followed by ozone and then u.v. light alone.