Electrochemical degradation of atrazine by BDD anode: Evidence from compound-specific stable isotope analysis and DFT simulations
| Autor: | Taobo Huang, Ting Wang, Ruoqi Ma, Huan Jiang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis 0208 environmental biotechnology Inorganic chemistry 02 engineering and technology Fractionation Dioxoles 010501 environmental sciences Chemical Fractionation Electrochemistry 01 natural sciences chemistry.chemical_compound Isotope fractionation Isotopes Environmental Chemistry Atrazine Electrodes 0105 earth and related environmental sciences Isotope analysis Quenching (fluorescence) Chemistry Public Health Environmental and Occupational Health General Medicine General Chemistry Pollution 020801 environmental engineering Anode Degradation (geology) Oxidation-Reduction Water Pollutants Chemical |
| Zdroj: | Chemosphere. 273 |
| ISSN: | 1879-1298 |
| Popis: | Direct charge transfer (DCT) and •OH attack played important roles in contaminant degradation by BDD electrochemical oxidation. Their separate contributions and potential bond-cleavage processes were required but lacking. Here, we carried out promising compound-specific isotope fractionation analysis (CSIA) to explore 13C and 2H isotope fractionation of atrazine (ATZ), followed by assessing the reaction pathway by BDD anode. The correlation of 2H and 13C fractionation allows to remarkably differentiate DCT process and •OH attack, with Λ values of 18.99 and 53.60, respectively. Radical quenching identified that •OH accounted for 79.0%–88.5% in the whole reaction. While CSIA methods provided biased results, which suggested that ATZ degradation exhibited two stages with •OH contributions of 24.6% and 84.3% respectively, confirming CSIA was more sensitive and provided more possibilities to estimate degradation processes. Combined with Fukui index and intermediate products identification, we deduced that dechlorination-hydroxylation mainly occurred in the first 30 min by DCT reaction. While lateral chain oxidation with C–N broken was the governing route once •OH was largely generated, with the production of DEA (m/z 188), DIA (m/z 174), DEIA (m/z 146) and DEIHA (m/z 128). Our results demonstrated that isotope fractionation can offer “isotopic footprints” for identifying the rate-limiting steps and bond breakage process, and opens new avenues for degradation pathways of contaminants. |
| Databáze: | OpenAIRE |
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