Study on the role of hydroperoxyl radical in degradation of p-nitrophenol attacked by hydroxyl radical using photolytical technique

Abstract

In order to investigate the possible role of hydroperoxyl radical (HO2 center dot) in the degradation of p-nitrophenol (p-NP) attacked by hydroxyl radical ((OH)-O-center dot), a series of experiment have been elaborately designed using UV light photolysis, pulse radiolysis and intermediate analysis. It has been demonstrated that (OH)-O-center dot is the dominant reactive oxygen specie, meanwhile both O-2 and HO2 center dot can enhance the degradation efficiency of p-NP. The accelerative effect of HO2 center dot has firstly been distinguished from that of O-2 by identifying the products in the systems of p-NP + (OH)-O-center dot, p-NP + (OH)-O-center dot + O-2 and p-NP + (OH)-O-center dot + O-2 + HO2 center dot. The possible reaction mechanism involved in the degradation of p-NP has been proposed, especially in the presence and absence of HO2 center dot. The ring open of phenoxy-type radical may be the key step in the accelerative effect of HO2 center dot. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.