Chlorine/UV treatment of anatoxin-a by activation of the secondary amine functional group
| Autor: | Moshan Chen, Ernest R. Blatchley |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
0208 environmental biotechnology Photodissociation chemistry.chemical_element 02 engineering and technology 010501 environmental sciences Photochemistry 01 natural sciences 020801 environmental engineering chemistry.chemical_compound Reaction rate constant chemistry Functional group Chlorine Molecule Amine gas treating Photodegradation Dimethylamine 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Environmental Science: Water Research & Technology. 6:1412-1420 |
| ISSN: | 2053-1419 2053-1400 |
| DOI: | 10.1039/c9ew01112a |
| Popis: | Studies of the combined application of chlorine and UVC radiation (Cl/UV) have generally focused on target compound degradation by the combined effects of direct photolysis and reactions with radical intermediates. However, prechlorination also has the potential to impart structural changes on molecules that increase their sensitivity to direct photolysis. Specifically, the prechlorination of amines leads to formation of their N-chlorinated derivatives, which is important because the N–Cl bond is photolabile. The Cl/UV process was examined for degradation of the secondary amines anatoxin-a (ANTX-a) and dimethylamine. ANTX-a and dimethylamine were both shown to undergo rapid N-chlorination. The first-order rate constant for photodecomposition of N-chlorodimethylamine at 254 nm was estimated to be 1.13 ± 0.05 × 10−3 cm2 mJ−1, while dimethylamine does not absorb UV254 radiation. The photodegradation of Cl-ANTX-a was also observed to be faster than direct photolysis of ANTX-a. For comparison, a first-order rate constant for photodegradation of Cl-ANTX-a of 1.86 ± 0.05 × 10−3 cm2 mJ−1 at 254 nm was estimated for N-chlorinated anatoxin-a, as compared 1.19 ± 0.02 × 10−3 cm2 mJ−1 for anatoxin-a. The observed increase in first-order rate of photodegradation illustrated activation of anatoxin-a toward photolysis by prechlorination. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|