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Ozonation of 14C-labeled micropollutants – mineralization of labeled moieties and adsorption of transformation products to activated carbon

Betsholtz, Alexander LU ; Juárez, Rubén LU orcid ; Svahn, Ola LU ; Davidsson, Åsa LU orcid ; Cimbritz, Michael LU and Falås, Per LU (2022) In Water Research 221.
Abstract

Ozonation transformation products (OTPs) are largely unknown compounds that are formed during the ozonation of micropollutants, and it is uncertain to which extent these compounds can be removed by subsequent adsorption to activated carbon. Thus, 14C-labeled micropollutants were ozonated to generate 14C-labeled OTPs, for which the adsorption of the sum of all 14C-labeled OTPs to activated carbon could be determined, based on the adsorption of the labeled carbon. Further, 14CO2 traps were used to examine the mineralization of 14C-labeled moieties during ozonation. 14CO2-formation revealed a partial mineralization of the 14C-labeled moieties... (More)

Ozonation transformation products (OTPs) are largely unknown compounds that are formed during the ozonation of micropollutants, and it is uncertain to which extent these compounds can be removed by subsequent adsorption to activated carbon. Thus, 14C-labeled micropollutants were ozonated to generate 14C-labeled OTPs, for which the adsorption of the sum of all 14C-labeled OTPs to activated carbon could be determined, based on the adsorption of the labeled carbon. Further, 14CO2 traps were used to examine the mineralization of 14C-labeled moieties during ozonation. 14CO2-formation revealed a partial mineralization of the 14C-labeled moieties in all compounds except for propyl-labeled bisphenol A and O-methyl-labeled naproxen. A similar degree of mineralization was noted for different compounds labeled at the same moiety, including the carboxylic carbon in diclofenac and ibuprofen (∼40% at 1 g O3/g DOC) and the aniline ring in sulfamethoxazole and sulfadiazine (∼30% at 1 g O3/g DOC). Aromatic ring cleavage was also confirmed for bisphenol A, sulfamethoxazole, and sulfadiazine through the formation of 14CO2. The adsorption experiments demonstrated increased adsorption of micropollutants to powdered activated carbon after ozonation, which was connected to a decreased adsorption of dissolved organic matter (DOM). Conversely, the OTPs showed a substantial and successive decline in adsorption at increased ozone doses for all compounds, likely due to decreased hydrophobicity and aromaticity of the OTPs. These findings indicate that adsorption to activated carbon alone is not a viable removal method for a wide range of ozonation transformation products.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
C-labeling, Pharmaceuticals, Transformation products, Wastewater
in
Water Research
volume
221
article number
118738
publisher
Elsevier
external identifiers
  • scopus:85132726251
  • pmid:35738061
ISSN
0043-1354
DOI
10.1016/j.watres.2022.118738
language
English
LU publication?
yes
id
d4ec63f4-b011-48dd-a2a2-5777e93de140
date added to LUP
2022-09-15 14:53:33
date last changed
2024-06-23 22:01:21
@article{d4ec63f4-b011-48dd-a2a2-5777e93de140,
  abstract     = {{<p>Ozonation transformation products (OTPs) are largely unknown compounds that are formed during the ozonation of micropollutants, and it is uncertain to which extent these compounds can be removed by subsequent adsorption to activated carbon. Thus, <sup>14</sup>C-labeled micropollutants were ozonated to generate <sup>14</sup>C-labeled OTPs, for which the adsorption of the sum of all <sup>14</sup>C-labeled OTPs to activated carbon could be determined, based on the adsorption of the labeled carbon. Further, <sup>14</sup>CO<sub>2</sub> traps were used to examine the mineralization of <sup>14</sup>C-labeled moieties during ozonation. <sup>14</sup>CO<sub>2</sub>-formation revealed a partial mineralization of the <sup>14</sup>C-labeled moieties in all compounds except for propyl-labeled bisphenol A and O-methyl-labeled naproxen. A similar degree of mineralization was noted for different compounds labeled at the same moiety, including the carboxylic carbon in diclofenac and ibuprofen (∼40% at 1 g O<sub>3</sub>/g DOC) and the aniline ring in sulfamethoxazole and sulfadiazine (∼30% at 1 g O<sub>3</sub>/g DOC). Aromatic ring cleavage was also confirmed for bisphenol A, sulfamethoxazole, and sulfadiazine through the formation of <sup>14</sup>CO<sub>2</sub>. The adsorption experiments demonstrated increased adsorption of micropollutants to powdered activated carbon after ozonation, which was connected to a decreased adsorption of dissolved organic matter (DOM). Conversely, the OTPs showed a substantial and successive decline in adsorption at increased ozone doses for all compounds, likely due to decreased hydrophobicity and aromaticity of the OTPs. These findings indicate that adsorption to activated carbon alone is not a viable removal method for a wide range of ozonation transformation products.</p>}},
  author       = {{Betsholtz, Alexander and Juárez, Rubén and Svahn, Ola and Davidsson, Åsa and Cimbritz, Michael and Falås, Per}},
  issn         = {{0043-1354}},
  keywords     = {{C-labeling; Pharmaceuticals; Transformation products; Wastewater}},
  language     = {{eng}},
  month        = {{08}},
  publisher    = {{Elsevier}},
  series       = {{Water Research}},
  title        = {{Ozonation of <sup>14</sup>C-labeled micropollutants – mineralization of labeled moieties and adsorption of transformation products to activated carbon}},
  url          = {{http://dx.doi.org/10.1016/j.watres.2022.118738}},
  doi          = {{10.1016/j.watres.2022.118738}},
  volume       = {{221}},
  year         = {{2022}},
}