ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Photolytic degradation of triclosan in the presence of surfactants

Zhongliang Chen, Qijun Song, Guangqun Cao, and Yanfei Chen

School of Chemical and Material Engineering, Jiangnan University, 214122 Wuxi, China

E-mail: qsong@jiangnan.edu.cn

Received: 24 January 2008  Revised: 9 May 2008  Accepted: 5 June 2008

Abstract: The formation of 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) in the photolytic degradation of triclosan has evoked a great concern for its safety and environmental fate. The photochemical behaviour of triclosan in daily-used chemical products, in which triclosan is present in relatively high concentrations and coexists with surfactants, was, however, addressed less frequently. The present work is focused on the mechanistic aspects of triclosan photodegradation in an aqueous medium with a relatively high concentration (≥ 30 mg L⁻¹) and on the influence of pH (8.7 and 10.5) and surfactants (Triton X100, SDS, and CTMAB) on this process. The results demonstrated that photodegradation was strongly affected by the pH and the presence of surfactants. Photodegradation products, including 2,4-dichlorophenol (2,4-DCP), 5-chloro-2-(4-chlorophenoxyl)-phenol, 2,8-DCDD, dimers, trimers, and other intermediates, were identified. Based on the analysis of photoproducts, homolytic scission of ether bond, dechlorination, ring closure, and photo-polymerisation were proposed as the main routes of triclosan photodegradation.

Keywords: triclosan - photodegradation - photopolymerisation - dioxin - surfactants

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-008-0077-0

Chemical Papers 62 (6) 608–615 (2008)