Aqueous photodegradation of 4-tert-butylphenol: By-products, degradation pathway and theoretical calculation assessment.

4- tert -butylphenol (4- t -BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4- t -BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC–MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4- t -BP by hydroxyl radical (HO ) was also studied and H 2 O 2 was added to produce HO . 4- tert -butylcatechol and 4- tert -butylphenol dimer were produced in 4- t -BP direct photolysis. 4- tert -butylcatechol and hydroquinone were produced by the oxidation of HO . But the formation mechanism of 4- tert -butylcatechol in the two processes was different. The benzene ring was fractured in 4- t -BP oxidation process and 29% of TOC was degraded after 16 h irradiation. [ABSTRACT FROM AUTHOR]