Asfaw, Berhane Abrha ; Sakaguchi-Söder, Kaori ; Schiedek, Thomas ; Michelsen, Nils ; Bernstein, Anat ; Siebner, Hagar ; Schüth, Christoph (2023)
Isotopic evidence (δ¹³C, δ³⁷Cl, δ²H) for distinct transformation mechanisms of chloroform: catalyzed H₂-water system vs. zero-valent iron (ZVI).
In: Journal of Environmental Chemical Engineering, 11 (3)
doi: 10.1016/j.jece.2023.110005
Article, Bibliographie
This is the latest version of this item.
Abstract
Catalytic hydrodechlorination is an efficient technology for degrading organochlorinated compounds, such as chloroform (CF), into harmless products. Compound-specific stable isotope analysis (CSIA) of multiple elements is widely used for the investigation of degradation mechanisms. Yet, its application in the study of catalytic hydrodechlorination is still limited. We have applied CSIA to derive chlorine, carbon, and hydrogen isotope enrichment factors (ε) during the degradation of CF over Pd/Al₂O₃ and over Rh/Al₂O₃. In addition, the enrichment factors for the same isotopes were derived for the reaction of CF with zero-valent iron (ZVI) for comparison. For the reactions of CF over Pd/Al₂O₃ and Rh/Al₂O₃, εC values (−21.9±0.25 ‰ and −23.4±2.3 ‰) and εCl values (−12.1±1.7 ‰ and −10.3±0.6 ‰) were determined, respectively. The corresponding εC and εCl values, for the dechlorination of CF with ZVI were −22.2±2.8 ‰ and −4.7±0.45 ‰, respectively. The apparent kinetic isotope effects (AKIE) of Cl suggest that the transformation mechanism in the catalyzed hydrogen-water system is a non-concerted reaction, unlike the known reductive dechlorination of CF with ZVI. Moreover, dual-isotope slopes (ΛC/Cl) for both catalyzed reactions (ΛPd = 1.8±0.13 and ΛRh = 2.1±0.14) are markedly different than for the ZVI (ΛZVI = 5.8±0.41), reflecting that the reactions proceed in different mechanisms. For hydrogen isotopes, while there was no clear trend for the catalyzed reactions, an inverse secondary hydrogen isotope effect was observed for the reaction of CF with ZVI.
| Item Type: | Article |
|---|---|
| Erschienen: | 2023 |
| Creators: | Asfaw, Berhane Abrha ; Sakaguchi-Söder, Kaori ; Schiedek, Thomas ; Michelsen, Nils ; Bernstein, Anat ; Siebner, Hagar ; Schüth, Christoph |
| Type of entry: | Bibliographie |
| Title: | Isotopic evidence (δ¹³C, δ³⁷Cl, δ²H) for distinct transformation mechanisms of chloroform: catalyzed H₂-water system vs. zero-valent iron (ZVI) |
| Language: | English |
| Date: | 2023 |
| Place of Publication: | Amsterdam |
| Publisher: | Elsevier |
| Journal or Publication Title: | Journal of Environmental Chemical Engineering |
| Volume of the journal: | 11 |
| Issue Number: | 3 |
| Collation: | 9 Seiten |
| DOI: | 10.1016/j.jece.2023.110005 |
| Corresponding Links: | |
| Abstract: | Catalytic hydrodechlorination is an efficient technology for degrading organochlorinated compounds, such as chloroform (CF), into harmless products. Compound-specific stable isotope analysis (CSIA) of multiple elements is widely used for the investigation of degradation mechanisms. Yet, its application in the study of catalytic hydrodechlorination is still limited. We have applied CSIA to derive chlorine, carbon, and hydrogen isotope enrichment factors (ε) during the degradation of CF over Pd/Al₂O₃ and over Rh/Al₂O₃. In addition, the enrichment factors for the same isotopes were derived for the reaction of CF with zero-valent iron (ZVI) for comparison. For the reactions of CF over Pd/Al₂O₃ and Rh/Al₂O₃, εC values (−21.9±0.25 ‰ and −23.4±2.3 ‰) and εCl values (−12.1±1.7 ‰ and −10.3±0.6 ‰) were determined, respectively. The corresponding εC and εCl values, for the dechlorination of CF with ZVI were −22.2±2.8 ‰ and −4.7±0.45 ‰, respectively. The apparent kinetic isotope effects (AKIE) of Cl suggest that the transformation mechanism in the catalyzed hydrogen-water system is a non-concerted reaction, unlike the known reductive dechlorination of CF with ZVI. Moreover, dual-isotope slopes (ΛC/Cl) for both catalyzed reactions (ΛPd = 1.8±0.13 and ΛRh = 2.1±0.14) are markedly different than for the ZVI (ΛZVI = 5.8±0.41), reflecting that the reactions proceed in different mechanisms. For hydrogen isotopes, while there was no clear trend for the catalyzed reactions, an inverse secondary hydrogen isotope effect was observed for the reaction of CF with ZVI. |
| Uncontrolled Keywords: | CSIA, Chloroform, Catalytic hydrodechlorination, Pd/Al2O3, Rh/Al2O3, ZVI |
| Identification Number: | Artikel-ID: 110005 |
| Classification DDC: | 500 Science and mathematics > 550 Earth sciences and geology 600 Technology, medicine, applied sciences > 624 Civil engineering and environmental protection engineering |
| Divisions: | 11 Department of Materials and Earth Sciences 11 Department of Materials and Earth Sciences > Earth Science 11 Department of Materials and Earth Sciences > Earth Science > Department of Soil Mineralogy and Soil Chemistry 13 Department of Civil and Environmental Engineering Sciences 13 Department of Civil and Environmental Engineering Sciences > Institute IWAR 13 Department of Civil and Environmental Engineering Sciences > Institute IWAR > Material Flow Management and Resource Economy |
| Date Deposited: | 30 Jul 2024 06:03 |
| Last Modified: | 30 Jul 2024 08:44 |
| PPN: | 520211677 |
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| Suche nach Titel in: | TUfind oder in Google |
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Isotopic evidence (δ¹³C, δ³⁷Cl, δ²H) for distinct transformation mechanisms of chloroform: Catalyzed H₂-water system vs. zero-valent iron (ZVI). (deposited 29 Jul 2024 14:17)
- Isotopic evidence (δ¹³C, δ³⁷Cl, δ²H) for distinct transformation mechanisms of chloroform: catalyzed H₂-water system vs. zero-valent iron (ZVI). (deposited 30 Jul 2024 06:03) [Currently Displayed]
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