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 (HO 2 ) in the degradation of p-nitrophenol (p-NP) attacked by hydroxyl radical ( OH), a series of experiment have been elaborately designed using UV light photolysis, pulse radiolysis and intermediate analysis. It has been demonstrated that OH is the dominant reactive oxygen specie, meanwhile both O 2 and HO 2 can enhance the degradation efficiency of p-NP. The accelerative effect of HO 2 has firstly been distinguished from that of O 2 by identifying the products in the systems of p-NP +  OH, p-NP +  OH + O 2 and p-NP +  OH + O 2  + HO 2 . The possible reaction mechanism involved in the degradation of p-NP has been proposed, especially in the presence and absence of HO 2 . The ring open of phenoxy-type radical may be the key step in the accelerative effect of HO 2 .