Dual roles of fulvic acid on the photodegradation of propranolol under different light-source irradiation

The photodegradation behaviors of propranolol(PRO) in solutions containing fulvic acid were studied under different light source irradiation. PRO degraded fast by direct photolysis under UV-vis irradiation. The UV photolysis process of PRO involved the triplet state of PRO( 3 PRO*) and self –sensitization decomposition. Under simulated solar irradiation, PRO photodegraded fast through 3 PRO* decomposition mainly. Under UV-vis irradiation, the PRO photodegradation was suppressed by SRFA and PLFA. Under simulated solar irradiation, SRFA and PLFA promoted PRO photolysis and the effects increased with increasing FA concentration. Compared with SRFA, PLFA owns higher reactive oxygen species (ROS) generation ability. SRFA and PLFA could suppress the reaction of PRO and ROS and the inhibition of SRFA is more significant than that of PLFA. This study demonstrates that DOM plays dual roles in the photodegradation of PRO acting as a sensitizer and quencher under different light source irradiation.