Micropollutants as internal probe compounds to assess UV fluence and hydroxyl radical exposure in UV/H2O2 treatment
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Authors
Wünsch, Robin
Mayer, Carina
Plattner, Julia
Wülser, Richard
Gebhardt, Jens
Hübner, Uwe
Canonica, Silvio
von Gunten, Urs
Author (Corporation)
Publication date
18.02.2021
Typ of student thesis
Course of study
Type
01A - Journal article
Editors
Editor (Corporation)
Supervisor
Parent work
Water Research
Special issue
DOI of the original publication
Link
Series
Series number
Volume
195
Issue / Number
Pages / Duration
Patent number
Publisher / Publishing institution
Elsevier
Place of publication / Event location
Edition
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Abstract
Organic micropollutants (MPs) are increasingly detected in water resources, which can be a concern for
human health and the aquatic environment. Ultraviolet (UV) radiation based advanced oxidation pro-
cesses (AOP) such as low-pressure mercury vapor arc lamp UV/H2O2 can be applied to abate these MPs.
During UV/H2O2 treatment, MPs are abated primarily by photolysis and reactions with hydroxyl radicals
(•OH), which are produced in situ from H2O2 photolysis. Here, a model is presented that calculates the
applied UV fluence (Hcalc) and the •OH exposure (CT•OH,calc) from the abatement of two selected MPs,
which act as internal probe compounds. Quantification of the UV fluence and hydroxyl radical exposure
was generally accurate when a UV susceptible and a UV resistant probe compound were selected, and
both were abated at least by 50 %, e.g., iopamidol and 5-methyl-1H-benzotriazole. Based on these key
parameters a model was developed to predict the abatement of other MPs. The prediction of abatement
was verified in various waters (sand filtrates of rivers Rhine and Wiese, and a tertiary wastewater efflu-
ent) and at different scales (laboratory experiments, pilot plant). The accuracy to predict the abatement of
other MPs was typically within ±20 % of the respective measured abatement. The model was further as-
sessed for its ability to estimate unknown rate constants for direct photolysis (kUV,MP) and reactions with
•OH (k•OH,MP). In most cases, the estimated rate constants agreed well with published values, considering
the uncertainty of kinetic data determined in laboratory experiments. A sensitivity analysis revealed that
in typical water treatment applications, the precision of kinetic parameters (kUV,MP for UV susceptible and
k•OH,MP for UV resistant probe compounds) have the strongest impact on the model’s accuracy
Keywords
OH-radical exposure, UV/H2O2 AOP in-situ probe compounds, Water treatment, Sensitivity analysis, Kinetic modeling
Subject (DDC)
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ISBN
ISSN
0043-1354
1879-2448
1879-2448
Language
English
Created during FHNW affiliation
Yes
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the complete publication
Open access category
Hybrid
License
Citation
Wünsch, R., Mayer, C., Plattner, J., Eugster, F., Wülser, R., Gebhardt, J., Hübner, U., Canonica, S., von Gunten, U., & Wintgens, T. (2021). Micropollutants as internal probe compounds to assess UV fluence and hydroxyl radical exposure in UV/H2O2 treatment. Water Research, 195. https://doi.org/10.1016/j.watres.2021.116940