Dual Carbon–Bromine Stable Isotope Analysis Allows Distinguishing Transformation Pathways of Ethylene Dibromide
Autor: | Kevin Kuntze, Faina Gelman, Ivonne Nijenhuis, Ludwik Halicz, Anna Kozell, Hans H. Richnow |
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Rok vydání: | 2016 |
Předmět: |
Carbon Isotopes
Bromine Chemistry Ethylene Dibromide Inorganic chemistry chemistry.chemical_element General Chemistry Chemical Fractionation 010501 environmental sciences Biodegradation Alkaline hydrolysis (body disposal) 010402 general chemistry 01 natural sciences Carbon 0104 chemical sciences Hydrolysis Biodegradation Environmental Isotope fractionation Isotopes of bromine Environmental Chemistry Chemical decomposition 0105 earth and related environmental sciences |
Zdroj: | Environmental Science & Technology. 50:9855-9863 |
ISSN: | 1520-5851 0013-936X |
Popis: | The present study investigated dual carbon-bromine isotope fractionation of the common groundwater contaminant ethylene dibromide (EDB) during chemical and biological transformations, including aerobic and anaerobic biodegradation, alkaline hydrolysis, Fenton-like degradation, debromination by Zn(0) and reduced corrinoids. Significantly different correlation of carbon and bromine isotope fractionation (ΛC/Br) was observed not only for the processes following different transformation pathways, but also for abiotic and biotic processes with, the presumed, same formal chemical degradation mechanism. The studied processes resulted in a wide range of ΛC/Br values: ΛC/Br = 30.1 was observed for hydrolysis of EDB in alkaline solution; ΛC/Br between 4.2 and 5.3 were determined for dibromoelimination pathway with reduced corrinoids and Zn(0) particles; EDB biodegradation by Ancylobacter aquaticus and Sulfurospirillum multivorans resulted in ΛC/Br = 10.7 and 2.4, respectively; Fenton-like degradation resulted in carbon isotope fractionation only, leading to ΛC/Br ∞. Calculated carbon apparent kinetic isotope effects ((13)C-AKIE) fell with 1.005 to 1.035 within expected ranges according to the theoretical KIE, however, biotic transformations resulted in weaker carbon isotope effects than respective abiotic transformations. Relatively large bromine isotope effects with (81)Br-AKIE of 1.0012-1.002 and 1.0021-1.004 were observed for nucleophilic substitution and dibromoelimination, respectively, and reveal so far underestimated strong bromine isotope effects. |
Databáze: | OpenAIRE |
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