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Mumbo, J. ; Deyerling, D. ; Henkelmann, B. ; Pfister, G. ; Schramm, K.-W.

Photodegradative fate and potential phototoxic products of bromocarbazoles and chlorocarbazoles in water.

Environ. Sci. Pollut. Res. 24, 27525–27538 (2017)
DOI PMC
Open Access Green möglich sobald Postprint bei der ZB eingereicht worden ist.
Bromocarbazoles and chlorocarbazoles are emerging environmental contaminants that have been reported to be persistent and possessing dioxin-like toxicity; however, their photodegradative fate in water is unknown. The photodegradation of 3-bromocarbazole, 3-chlorocarbazole, and 3,6-dichlorocarbazole was determined in ultrapure water. They proceeded by direct photolysis and followed first-order kinetics. The rate constants (k) were 0.4838, 0.3454, and 0.4422 h(-1) corresponding to half-lives (t 1/2) 1.81, 2.01, and 1.62, while the quantum yields (Ф) were 0.232, 0.180, and 0.295 respectively. The maximum wavelengths of absorption (λ max) were in the near ultraviolet region (295, 296, 299, and 301 nm) implying these compounds are likely to degrade slowly under sunlight in natural aquatic environment. The molar extinction coefficients (ε) determined in acetonitrile were 18,573, 17,028, 13,385, and 14,010 L mol(-1) cm(-1), respectively, the latter being 3,6-dibromocarbazole. A bathochromic shift was observed with halogen addition on their respective mono-substituted congeners. Bromocarbazoles were observed to degrade faster in water than chlorocarbazoles. In addition, photodegradation was estimated to proceed faster in summer than in winter, in natural water system at 50° N latitude. In the absence of light, hydrolytic degradation occurred but proceeded very slowly. Hexahydroxybenzene and trihydroxycarbazole were positively identified as the likely photoproducts with the former being a known toxic compound. Dehalogenation, oxidative cleavage, hydroxylation, and hydrolysis are suggested as the major photodegradation mechanisms in water, yielding phototoxic products that may be of enhanced toxicity than the parent compounds.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
Schlagwörter Bromocarbazoles ; Chlorocarbazoles ; Hydrolysis ; Photodegradation ; Phototoxic Products ; Water; Polycyclic Aromatic-hydrocarbons; Polyhalogenated Carbazoles; Photochemical Degradation; Aquatic Environments; Direct Photolysis; Chlorine Atom; N-acetyl; Sediments; Nitrate; Pahs
ISSN (print) / ISBN 0944-1344
e-ISSN 1614-7499
Zeitschrift Environmental Science and Pollution Research
Quellenangaben Band: 24, Heft: 35, Seiten: 27525–27538 Artikelnummer: , Supplement: ,
Verlag Springer
Verlagsort Heidelberg
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) PPM-MEX-Molecular EXposomics (MEX)