TY - JOUR U1 - Wissenschaftlicher Artikel A1 - Grimmig, Roman A1 - Gillemot, Philipp A1 - Kretschmer, Axel A1 - Günther, Klaus A1 - Baltruschat, Helmut A1 - Witzleben, Steffen T1 - Challenges in the determination of reactive oxygen species evolving during membrane water electrolysis for in situ ozone production JF - Journal of Water Process Engineering N2 - The treatment of ultrapure water with electrochemically produced O3 is a common means for disinfection yet leads to the formation of a variety of reactive oxygen species (ROS). The present study draws a comprehensive comparison between three commonly used photometric and fluorometric assays for ROS analysis and quantifies the individual signal responses for dissolved O3, ·OH and H2O2, respectively, to account for cross-sensitivities. By calibrating all combinations of assays and analytes, we developed a quantification procedure to reliably determine the actual ROS composition in ultrapure water environments for different operation conditions of a membrane water electrolyzer with PbO2 anodes down to concentrations of 0.97 μg L−1. While the ·OH formation rate can be described linearly over the observed current density range, substantial O3 evolution is only found for current densities of 0.75 A cm−2 and above (up to 3.7 μmol h−1 for J = 1.25 A cm−2). The formation of H2O2 is only observed when an organic carbon source is introduced into the solution. We further quantify the interference of H2O2 with the reading of the oxidation-reduction potential as a common water parameter and elaborate on its validity to monitor the peroxone process when both H2O2 and O3 are present simultaneously. KW - Reactive oxygen species KW - Oxidation-reduction-potential KW - Hydroxyl radicals KW - PEM water electrolysis KW - Ozone generator Y1 - 2024 UN - https://nbn-resolving.org/urn:nbn:de:hbz:1044-opus-84744 SN - 2214-7144 SS - 2214-7144 U6 - https://doi.org/10.1016/j.jwpe.2024.105623 DO - https://doi.org/10.1016/j.jwpe.2024.105623 VL - 64 SP - 11 S1 - 11 PB - Elsevier ER -