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Chlorination of chlortoluron: Kinetics, pathways and chloroform formation
- Source :
- Chemosphere. 83:909-916
- Publication Year :
- 2011
- Publisher :
- Elsevier BV, 2011.
-
Abstract
- Chlortoluron chlorination is studied in the pH range of 3–10 at 25 ± 1 °C. The chlorination kinetics can be well described by a second-order kinetics model, first-order in chlorine and first-order in chlortoluron. The apparent rate constants were determined and found to be minimum at pH 6, maximum at pH 3 and medium at alkaline conditions. The rate constant of each predominant elementary reactions (i.e., the acid-catalyzed reaction of chlortoluron with HOCl, the reaction of chlortoluron with HOCl and the reaction of chlortoluron with OCl − ) was calculated as 3.12 (± 0.10) × 10 7 M −2 h −1 , 3.11 (±0.39) × 10 2 M −1 h −1 and 3.06 (±0.47) × 10 3 M −1 h −1 , respectively. The main chlortoluron chlorination by-products were identified by gas chromatography–mass spectrometry (GC–MS) with purge-and-trap pretreatment, ultra-performance liquid chromatography–electrospray ionization-MS and GC-electron capture detector. Six volatile disinfection by-products were identified including chloroform (CF), dichloroacetonitrile, 1,1-dichloropropanone, 1,1,1-trichloropropanone, dichloronitromethane and trichloronitromethane. Degradation pathways of chlortoluron chlorination were then proposed. High concentrations of CF were generated during chlortoluron chlorination, with maximum CF yield at circumneutral pH range in solution.
- Subjects :
- Reaction mechanism
Environmental Engineering
Halogenation
Health, Toxicology and Mutagenesis
Kinetics
chemistry.chemical_element
Water Purification
chemistry.chemical_compound
Reaction rate constant
Elementary reaction
Chlorine
Environmental Chemistry
Chloroform
Chromatography
Herbicides
Phenylurea Compounds
Public Health, Environmental and Occupational Health
General Medicine
General Chemistry
Hydrogen-Ion Concentration
Pollution
Electron capture detector
chemistry
Chlortoluron
Water Pollutants, Chemical
Subjects
Details
- ISSN :
- 00456535
- Volume :
- 83
- Database :
- OpenAIRE
- Journal :
- Chemosphere
- Accession number :
- edsair.doi.dedup.....6f52ad66b8d0d77180e5c54fb428777e