Photochemical conversion of triclosan to 2,8-dichlorodibenzo-p-dioxin in aqueous solution

Latch, Douglas E.; Packer, Jennifer L.; Arnold, William A.; McNeill, Kristopher

doi:10.1016/s1010-6030(03)00103-5

Cited by 250 publications

(170 citation statements)

References 36 publications

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“…Indeed, the significant decrease of A further photochemistry issue is that the decrease of DOC is expected to enhance as well the direct photolysis of organic compounds. Indeed, the chromophoric portion of DOM competes with other dissolved molecules for radiation absorption (Lam et al, 2003;Latch et al, 2003) and, in some cases, DOM can decrease the direct photolysis quantum yields of other substrates (Vione et al, 2010b). Figure 7 shows the PCA analysis (PC1 vs. PC2) of the data, grouped by season.…”

Section: Principal Components Analysis Resultsmentioning

confidence: 99%

A model approach to assess the long-term trends of indirect photochemistry in lake water. The case of Lake Maggiore (NW Italy)

Minella

Rogora

Vione

et al. 2011

Science of The Total Environment

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Section: Principal Components Analysis Resultsmentioning

confidence: 99%

A model approach to assess the long-term trends of indirect photochemistry in lake water. The case of Lake Maggiore (NW Italy)

Minella

Rogora

Vione

et al. 2011

Science of The Total Environment

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“…From these results, it can be concluded that Fenton-like oxidation is a really efficient technique for triclosan abatement. The formation of dioxins from triclosan upon sun-light exposition has been reported in the literature [17,[19][20][21]. In order to investigate in depth the possible occurrence of these compounds upon Fenton-like oxidation in our working conditions the final effluents after one-hour reaction time were analyzed by SBSE-GC Â GC-TOF-MS.…”

Section: Oxidation Byproductsmentioning

confidence: 99%

“…Ozonation suffers from the potential generation of carcinogenic byproducts [18] as well as from corrosion problems. On the other hand, exposure of triclosan to sunlight or UV irradiation in photocatalytic processes can lead to the formation of highly toxic and persistent chlorinated byproducts like 2,8-dichlorodibenzo-p-dioxin [17,[19][20][21]. Therefore, other potential solutions need to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Triclosan breakdown by Fenton-like oxidation

Muñoz

Pedro

Casas

et al. 2012

Chemical Engineering Journal

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Fenton-like oxidation has proved to be highly efficient for the removal of triclosan, a highly toxic emerging water pollutant. From 10mg/L starting aqueous solutions complete conversion of triclosan was achieved in less than 1h at 25°C and around 20min at 50°C with 1mg/L Fe3+ and H2O2 at the theoretical stoichiometric amount (25mg/L). From the evolution of byproducts a reaction pathway has been proposed according to which oxidation of triclosan gives rise to several aromatic intermediates (mainly, p-hydroquinone of triclosan and 2,4-dichlorophenol) which evolve to short-chain organic acids. These compounds are mineralized except oxalic acid. A dramatic decrease of ecotoxicity was achieved in a relatively short time (more than 95% in 15min at 35°C). The evolution of ecotoxicity is intimately related to the disappearance of triclosan, much more toxic than the aromatic oxidation intermediates. This disappearance was successfully described by a simple pseudo-first order rate equation with an apparent activation energy value close to 27kJ/mol. The apparent rate constant at 25°C was several orders of magnitude higher than the reported in the literature for other chlorophenolic compounds indicating a higher susceptibility of triclosan to OH radical attackThis research has been supported by the Spanish MICINN through the project CTQ2008-03988 and by the CM through the project S-2009/AMB-158

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“…It has been hypothesized that the presence of these toxic chemical compounds is derived from its synthesis [12] and also by intermolecular photochemical substitution reaction [13,14]. However, there is a controversy about the reliability of this fact and the real influence in water and wastewater environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Evidence of 2,7/2,8-dibenzodichloro-p-dioxin as a photodegradation product of triclosan in water and wastewater samples

Mezcúa

Gómez

Ferrer

et al. 2004

Analytica Chimica Acta

184

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A photodegradation study of triclosan, a commonly used antimicrobial agent, was carried out in order to investigate the formation of dibenzodichlorodioxin as a by-product of photodegradation in various environmental matrices and under different conditions. Deionized water and wastewater samples, spiked at 8 g/mL with triclosan, were irradiated with natural sunlight. Aliquots of the spiked water samples were taken at different times of irradiation and compounds were isolated from the water samples by solid-phase extraction. Separation and detection of the compounds and degradation products was accomplished by gas chromatography-mass spectrometry. A major photolysis degradation product of triclosan, 2,7/2,8-dibenzodichloro-p-dioxin, was identified in wastewater samples. The photolysis experiment showed the simultaneous disappearance of triclosan and the appearance of the dioxin dependent on the pH and the organic matter content. Furthermore, a pilot survey monitoring for influent and effluent waters from a wastewater treatment plant was carried out. The presence of triclosan in all wastewater samples analyzed was revealed and dioxin was found in 80% of the cases, in influents and effluents, thus indicating its input and persistence through the wastewater treatment process. This represents a major finding since dioxins are more toxic than triclosan. Moreover, the presence of such compounds in wastewaters revealed the immediate need to improve the "classical" water treatment techniques, as well as considering limitation in water re-use.

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Photochemical conversion of triclosan to 2,8-dichlorodibenzo-p-dioxin in aqueous solution

Cited by 250 publications

References 36 publications

A model approach to assess the long-term trends of indirect photochemistry in lake water. The case of Lake Maggiore (NW Italy)

A model approach to assess the long-term trends of indirect photochemistry in lake water. The case of Lake Maggiore (NW Italy)

Triclosan breakdown by Fenton-like oxidation

Evidence of 2,7/2,8-dibenzodichloro-p-dioxin as a photodegradation product of triclosan in water and wastewater samples

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