Influence of Humic Acid on the Photolysis of Triclosan in Different Dissociation Forms
2016
Chen, Lei | Wang, Zheng | Wang, Zhulai | Gu, Xin
Photolysis is a major transformation pathway for triclosan, an antibacterial agent frequently detected in aquatic environment. Though many studies have been conducted on the influence of dissolved organic matter on the photolysis of triclosan, there are still controversies and the mechanism involved is still not clear. In the present study, influence of humic acid on the photolysis of triclosan in molecular form and anionic form was investigated. Reactive substances involved were identified and photolysis pathways were proposed. The addition of humic acid significantly enhanced the photolysis of triclosan in molecular form and inhibited that of triclosan in anionic form. •OH and intra-humic acid ¹O₂ played the dorminant role in the enhanced photolysis of triclosan. Different photolysis pathways of triclosan in different forms in the presence of humic acid were proposed, and dioxin products were not found during the indirect photolysis. Here, we show that humic acid has the opposing effects on the photolysis of triclosan in different forms. These findings will help us better understand the photolysis process of triclosan in natural waters.
显示更多 [+] 显示较少 [-]