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Photocatalytic degradation kinetics and mechanisms of antibacterial triclosan in aqueous TiO 2 suspensions under simulated solar irradiation
Author(s) -
Stamatis Nikolaos,
Antonopoulou Maria,
Hela Dimitra,
Konstantinou Ioannis
Publication year - 2014
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.4387
Subject(s) - mineralization (soil science) , photocatalysis , triclosan , response surface methodology , degradation (telecommunications) , central composite design , kinetics , chemistry , aqueous solution , nuclear chemistry , chemical engineering , catalysis , irradiation , materials science , chromatography , organic chemistry , medicine , telecommunications , physics , pathology , quantum mechanics , computer science , nuclear physics , nitrogen , engineering
BACKGROUND The present study focuses on the photocatalytic transformation and mineralization of triclosan ( TCS ) using TiO 2 catalyst. The main objectives were: (a) to investigate the effect of TiO 2 , TCS concentration and irradiation intensity on the photocatalytic efficiency and to model the degradation and mineralization percentage of TCS using response surface methodology ( RSM ) based on central composite design ( CCD ); (b) to identify transformation products ( TPs ) and degradation mechanisms, (c) to assess the toxicity of the TPs . RESULTS The results from the RSM analysis indicated that all operating parameters studied have significant effects on TCS degradation and mineralization. A quadratic response surface model was found to fit the experimental data and was used to find the optimum experimental conditions. Scavenging experiments indicated that HO • radicals were principally responsible for TCS degradation. The transformation of TCS involved reactions of mono‐ and di‐ hydroxylation, dechlorination, and cleavage of the ether bond. Total detoxification of the treated solution was obtained after 30 min, as revealed by Microtox bioassay. CONCLUSION TCS can be effectively degraded and mineralized using TiO 2 under simulated solar light avoiding the formation of highly toxic TPs . RSM modeling provided a statistically accurate prediction of the optimum degradation and mineralization of TCS . © 2014 Society of Chemical Industry