Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Formation of Nitrophenolic Byproducts during UV-Activated Peroxydisulfate Oxidation in the Presence of Nitrate
https://orcid.org/0000-0001-6068-5820
UV-peroxydisulfate (UV/PDS) oxidation is a promising technology to degrade organic pollutants. In this study, we found that nitrate (NO3 –) could lead to the formation of toxic nitrophenolic byproducts during UV/PDS oxidation of natural organic matter (NOM). At a UV fluence of 4.49 × 105 mJ L–1, the formation of 4-nitrophenol, 4-hydroxy-3-nitrobenzoic acid, and 2,4-dinitrophenol reached 0.0084, 0.0324, and 0.0046 μM, respectively. NO2 • produced from the photolysis of NO3 – acted as the nitrating agent. Meanwhile, the phenolic moieties of NOM molecules were oxidized by SO4 •– through single-electron transfer, giving rise to phenoxyl radicals. The phenoxyl radicals coupled with NO2 • to generate nitrated byproducts. Although •OH was also formed in the UV/PDS process, theoretical computation suggests that the phenoxyl radicals were primarily ascribed to SO4 •–, because •OH preferentially reacted with NOM via addition mechanism resulting in hydroxylated intermediates. In addition, the aromatic carboxyl moieties of NOM molecules could be decarboxylated upon reaction with SO4 •– and transformed to phenolic intermediates, which also contributed to the nitrated byproducts formation. This study reveals a novel nitration mechanism that is specific to the UV/PDS process and raises concerns to the potential risks when the UV/PDS is applied to wastewaters with high levels of NO3 –.
Formation of Nitrophenolic Byproducts during UV-Activated Peroxydisulfate Oxidation in the Presence of Nitrate
https://orcid.org/0000-0001-6068-5820
UV-peroxydisulfate (UV/PDS) oxidation is a promising technology to degrade organic pollutants. In this study, we found that nitrate (NO3 –) could lead to the formation of toxic nitrophenolic byproducts during UV/PDS oxidation of natural organic matter (NOM). At a UV fluence of 4.49 × 105 mJ L–1, the formation of 4-nitrophenol, 4-hydroxy-3-nitrobenzoic acid, and 2,4-dinitrophenol reached 0.0084, 0.0324, and 0.0046 μM, respectively. NO2 • produced from the photolysis of NO3 – acted as the nitrating agent. Meanwhile, the phenolic moieties of NOM molecules were oxidized by SO4 •– through single-electron transfer, giving rise to phenoxyl radicals. The phenoxyl radicals coupled with NO2 • to generate nitrated byproducts. Although •OH was also formed in the UV/PDS process, theoretical computation suggests that the phenoxyl radicals were primarily ascribed to SO4 •–, because •OH preferentially reacted with NOM via addition mechanism resulting in hydroxylated intermediates. In addition, the aromatic carboxyl moieties of NOM molecules could be decarboxylated upon reaction with SO4 •– and transformed to phenolic intermediates, which also contributed to the nitrated byproducts formation. This study reveals a novel nitration mechanism that is specific to the UV/PDS process and raises concerns to the potential risks when the UV/PDS is applied to wastewaters with high levels of NO3 –.
Formation of Nitrophenolic Byproducts during UV-Activated Peroxydisulfate Oxidation in the Presence of Nitrate
https://orcid.org/0000-0001-6068-5820
UV-peroxydisulfate (UV/PDS) oxidation is a promising technology to degrade organic pollutants. In this study, we found that nitrate (NO3 –) could lead to the formation of toxic nitrophenolic byproducts during UV/PDS oxidation of natural organic matter (NOM). At a UV fluence of 4.49 × 105 mJ L–1, the formation of 4-nitrophenol, 4-hydroxy-3-nitrobenzoic acid, and 2,4-dinitrophenol reached 0.0084, 0.0324, and 0.0046 μM, respectively. NO2 • produced from the photolysis of NO3 – acted as the nitrating agent. Meanwhile, the phenolic moieties of NOM molecules were oxidized by SO4 •– through single-electron transfer, giving rise to phenoxyl radicals. The phenoxyl radicals coupled with NO2 • to generate nitrated byproducts. Although •OH was also formed in the UV/PDS process, theoretical computation suggests that the phenoxyl radicals were primarily ascribed to SO4 •–, because •OH preferentially reacted with NOM via addition mechanism resulting in hydroxylated intermediates. In addition, the aromatic carboxyl moieties of NOM molecules could be decarboxylated upon reaction with SO4 •– and transformed to phenolic intermediates, which also contributed to the nitrated byproducts formation. This study reveals a novel nitration mechanism that is specific to the UV/PDS process and raises concerns to the potential risks when the UV/PDS is applied to wastewaters with high levels of NO3 –.
Formation of Nitrophenolic Byproducts during UV-Activated Peroxydisulfate Oxidation in the Presence of Nitrate
Gao, Xu (Autor:in) / Zhang, Qi (Autor:in) / Yang, Ziyi (Autor:in) / Ji, Yuefei (Autor:in) / Chen, Jing (Autor:in) / Lu, Junhe (Autor:in)
ACS ES&T Engineering ; 2 ; 222-231
11.02.2022
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Influence of Nitrite on Ultraviolet-Activated Peroxydisulfate Degradation of 2,4-Dichlorophenol
| American Chemical Society | 2023
Formation of iodinated products in Fe (II)/peroxydisulfate (PDS) system
| DOAJ | 2021
Degradation of methylene blue using peroxydisulfate activated by zinc and sulfur functional biochar
| DOAJ | 2024
Compressed Earth Blocks Using Sediments and Alkali-Activated Byproducts
| DOAJ | 2022