Determination of hydroxyl radicals using coumarin and coumarin-3-carboxylic acid during gamma radiolysis and heterogeneous photocatalysis
Coumarin and 3-carboxycoumarinic acid, two fluorescent probes commonly used for HO• detection has been used during gamma radiolysis and heterogeneous photocatalysis. The O2 dependency and the radiation yield of their hydroxylated flurescent products (7-hydroxycoumarin and 7-hydroxy-3-carboxycoumarin...
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| Format: | Book part |
| Published: |
2019
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| Series: | Proceedings of the International Symposium on Analytical and Environmental Problems
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| Kulcsszavak: | Környezetkémia, Fotokatalízis |
| Online Access: | http://acta.bibl.u-szeged.hu/64766 |
| Summary: | Coumarin and 3-carboxycoumarinic acid, two fluorescent probes commonly used for HO• detection has been used during gamma radiolysis and heterogeneous photocatalysis. The O2 dependency and the radiation yield of their hydroxylated flurescent products (7-hydroxycoumarin and 7-hydroxy-3-carboxycoumarinic acid) has been investigated during gamma radiolysis. The radiation yields were found to be 1.2(±0.2) % in O2-free solutions, while it was 2.9 (±0.06) % in the presence of O2, proving the importance of peroxyl radicals in the formation of these products. The results obtained from radiolysis experiments, were employed during heterogeneous photocatalysis performed with commercial TiO2 catalyst. The effect of dissolved O2 was also investigated, as its electron scavanging role during photocatalyis is also important. The formation rate of HO• during photocatalysis was calculated from the formation rate of the fluorescent products, and were found to be 1.8×10-7 mol dm-3 s -1 , while the quantum efficiency for its formation is 0.0038. |
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| Physical Description: | 23-27 |
| ISBN: | 978-963-306-702-4 |