Details zur Publikation
|Titel (primär)||Investigation of humic substance photosensitized reactions via carbon and hydrogen isotope fractionation|
|Autor||Zhang, N.; Schindelka, J.; Herrmann, H.; George, C.; Rosell, M.; Herrero-Martín, S.; Klán, P.; Richnow, H.-H.|
|Journal / Serie||Environmental Science & Technology|
Humic substances (HS) acting as photosensitizers can generate a variety of reactive species, such as OH radicals and excited triplet states (3HS*), promoting the degradation of organic compounds. Here, we apply compound-specific stable isotope analysis (CSIA) to characterize photosensitized mechanisms employing fuel oxygenates, such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), as probes. In oxygenated aqueous media, Λ (Δδ2H/Δδ13C) values of 23 ± 3 and 21 ± 3 for ETBE obtained by photosensitization by Pahokee Peat Humic Acid (PPHA) and Suwannee River Fulvic Acid (SRFA), respectively, were in the range typical for H-abstraction by OH radicals generated by photolysis of H2O2 (Λ = 24 ± 2). However, 3HS* may become a predominant reactive species upon the quenching of OH radicals (Λ = 14 ± 1), and this process can also play a key role in the degradation of ETBE by PPHA photosensitization in deoxygenated media (Λ = 11 ± 1). This is in agreement with a model photosensitization by rose bengal (RB2–) in deoxygenated aqueous solutions resulting in one-electron oxidation of ETBE (Λ = 14 ± 1). Our results demonstrate that the use of CSIA could open new avenues for the assessment of photosensitization pathways.
|Zhang, N., Schindelka, J., Herrmann, H., George, C., Rosell, M., Herrero-Martín, S., Klán, P., Richnow, H.-H. (2015):
Investigation of humic substance photosensitized reactions via carbon and hydrogen isotope fractionation
Environ. Sci. Technol. 49 (1), 233 - 242