Photodegradation of fragrance materials and triclosan in water: Direct photolysis and photosensitized degradation

Abstract

The present study aims to assess the photodegradation of three polycyclic musk compounds (OTNE, HHCB, and AHTN) and one disinfectant (triclosan) under simulated sunlight irradiation using a halogen lamp in pH-adjusted DI water, natural waters, and humic acid solution. The degradation induced by hydroxyl radical was examined with the addition of 2-propanol. The targeted compounds were considerably decreased in several days under irradiation, except for triclosan for blank water, with the pseudo-first-order rate constants in the order of one per day at the maximum. They were degraded with the paths of both direct and indirect photosensitized processes, with the hydroxyl radical and others. The main findings were that OTNE direct photolysis was possibly influenced by pH. HHCB photosensitized pathway was more eminent than that of AHTN, and triclosan was degraded mostly by the photosensitized process. The major influential factors were found to differ with the compounds and solution conditions, which intensifies the importance of the consideration of key factors for predicting the degree of photodegradation in water environments. • Direct photolysis and photosensitized degradation were evaluated simultaneously. • Triclosan was mostly degraded by photosensitized pathway, not by direct photolysis. • ONTE direct photolysis was influenced by pH.