Environmental Science:: Processes & Impacts
In this study it was observed that, during long-term irradiations (>1 day) of natural waters, the methods for measuring hydroxyl radical (˙OH) formation rates based upon sequentially determined cumulative concentrations of photoproducts from probes significantly underestimate actual ˙OH formation rates. Performing a correction using the photodegradation rates of the probe products improves the ˙OH estimation for short term irradiations (<1 day), but not long term irradiations. Only the ‘instantaneous’ formation rates, which were obtained by adding probes to aliquots at each time point and irradiating these sub-samples for a short time (≤2 h), were found appropriate for accurately estimating ˙OH photochemical formation rates during long-term laboratory irradiation experiments. Our results also showed that in iron- and dissolved organic matter (DOM)-rich water samples, ˙OH appears to be mainly produced from the Fenton reaction initially, but subsequently from other sources possibly from DOM photoreactions. Pathways of ˙OH formation in long-term irradiations in relation to H2O2 and iron concentrations are discussed.
Original Publication Citation
Sun, L. N., Chen, H. M., Abdulla, H. A., & Mopper, K. (2014). Estimating hydroxyl radical photochemical formation rates in natural waters during long-term laboratory irradiation experiments. Environmental Science: Processes & Impacts, 16(4), 757-763. doi:10.1039/c3em00587a
0000-0003-2460-838X (Chen), 0000-0001-8089-6019 (Mopper)
Sun, Luni; Chen, Hongmei; Abdulla, Hussain A.; and Mopper, Kenneth, "Estimating Hydroxyl Radical Photochemical Formation Rates in Natural Waters During Long-Term Laboratory Irradiation Experiments" (2014). Chemistry & Biochemistry Faculty Publications. 149.