Carbon, hydrogen, nitrogen and chlorine isotope fractionation during 3-chloroaniline transformation in aqueous environments by direct photolysis, TiO2 photocatalysis and hydrolysis
This study investigates carbon, hydrogen, nitrogen and chlorine isotope fractionation during the transformation of 3-chloroaniline (3-CA) via direct photolysis, TiO<sub>2</sub> photocatalytic degradation at neutral condition and hydrolysis at pH 3, pH 7 and pH 11. Direct photolysis and ∙OH reaction (UV/H<sub>2</sub>O<sub>2</sub>) showed similar inverse isotope fractionation (ε) for carbon (1.9 ± 0.4 ‰ and 1.9 ± 0.6 ‰), for hydrogen (6.9 ± 1.6 ‰ and 5.0 ± 2.6 ‰), and inverse chlorine (13.9 ± 3.8 ‰ and 11.9 ± 2.9 ‰) and no nitrogen isotope fractionation, respectively. In contrast, significantly different normal carbon (-0.5 ± 0.1 ‰), inverse hydrogen (6.6 ± 1.5 ‰), and normal nitrogen (-0.8 ± 0.2 ‰) and inverse chlorine (5.2 ± 3.7 ‰) isotope fractionations were observed for the photocatalysis of 3-CA by TiO<sub>2</sub> indicating a different degradation pathway as expected from ∙OH. For hydrolysis, inverse carbon (0.7 ± 0.3 ‰) and hydrogen (12.5 ± 3.3 ‰) isotope fractionation have been found at pH 3 while a normal carbon isotope fractionation was observed at pH 7 (-0.9 ± 0.3 ‰) and pH 11 (-1.3 ± 0.4 ‰), respectively. The correlation of <sup>2</sup>H and <sup>13</sup>C, <sup>15</sup>N and <sup>13</sup>C, and <sup>37</sup>Cl and <sup>13</sup>C isotope fractionation (Λ) allowed to distinguish direct photodegradation (Λ<sub>H</sub><sub>C</sub> = -4.6 ± 1.7 (Λ<sub>H</sub><sub>C-YORK</sub>=-5.2 ± 1.0) and Λ<sub>Cl-</sub><sub>C</sub> = 8.7 ± 0.9 (Λ<sub>Cl-C-YORK</sub>=8.0 ± 0.3)), UV/H<sub>2</sub>O<sub>2</sub> oxidation (Λ<sub>H</sub><sub>C</sub> = -4.7 ± 1.0 (Λ<sub>H</sub><sub>C-YORK</sub>=-4.5 ± 0.6) and Λ<sub>Cl-</sub><sub>C</sub> = 6.7 ± 0.8 (Λ<sub>Cl-C-YORK</sub>=7.0 ± 1.0)), UV/TiO<sub>2</sub> photocatalysis (Λ<sub>H</sub><sub>C</sub> = -9.2 ± 3.1 (Λ<sub>H</sub><sub>C-YORK</sub>=-9.3 ± 1.4), Λ<sub>Cl-C</sub> = -10.2 ± 1.5 (Λ<sub>Cl-C-YORK</sub>=-12.4 ± 1.7) and Λ<sub>N</sub><sub>C</sub> -2.2 ± 0.3 (Λ<sub>N</sub><sub>C-YORK</sub>=-2.3 ± 0.4)) and the modes of hydrolysis (Λ<sub>H</sub><sub>C</sub> = 15.2 ± 5.3 (Λ<sub>H</sub><sub>C-YORK</sub>=17.9 ± 2.9) and Λ<sub>Cl-</sub><sub>C</sub> = 0.9 ± 0.2 (Λ<sub>Cl-C-YORK</sub>=1.1 ± 0.1) at pH 3) of 3-CA. The results were mechanistically interpreted highlighting the potential of CSIA to elucidate chemical oxidation and hydrolysis mechanisms of 3-CA.
Authors
- Hartmut Herrmann (ORCID: https://orcid.org/0000-0001-7044-2101)
- Hans H. Richnow (ORCID: https://orcid.org/0000-0002-6144-4129)
- Steffen Kümmel (ORCID: https://orcid.org/0000-0002-8114-8116)
- Thomas Schaefer (ORCID: https://orcid.org/0000-0001-7995-4285)
- Hao Li (ORCID: https://orcid.org/0009-0000-3369-9063)
- Jun Yao (ORCID: https://orcid.org/0000-0002-4991-0369)
- Ning Min
Institutions
- Helmholtz Centre for Environmental Research (DE)
- China University of Geosciences (Beijing) (CN)
- Leibniz Institute for Tropospheric Research (DE)
Publication Details
- Journal
- Water Research
- Published
- 2024-12-27
- DOI
- https://doi.org/10.1016/j.watres.2024.122956
- Citations
- 5
- Primary Topic
- TiO2 Photocatalysis and Solar Cells
- Type
- article
- Field-Weighted Citation Impact
- 0.51
Funders
- National Natural Science Foundation of China
- China Scholarship Council
- Postdoctoral Research Foundation of China
- National Major Science and Technology Projects of China