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Degradation kinetics of prometryn and formation of disinfection by-products during chlorination
- Source :
- Chemosphere. 276:130089
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Prometryn is a herbicide that is widely used and frequently detected in aqueous environment and soil. Prometryn is chemically stable, biologically toxic, and easily to accumulate in living bodies, which can cause accumulate in the environment and acute and chronic toxicity to living creatures. In this study, factors affecting the degradation kinetics of prometryn chlorination were studied, including solution pH, bromide and ammonium concentrations, and temperature. Prometryn reacted quickly with aqueous chlorine following the pseudo-first-order kinetics. The maximum pseudo-first-order rate constant (kapp) appeared at pH 5 with the observed rate constant (kobs) as 190. 08 h−1; the minimum value of kapp reached at pH 9 with kobs as 5.26 h−1. The presence of Br− and increase of temperature both accelerated the degradation rate of prometryn during chlorination. The activation energy was calculated as 31.80 kJ/mol. Meanwhile 6 disinfection by-products (DBPs) were detected, namely: chloroform (CF), trichloroacetonitrile (TCAN), dichloroacetonitrile (DCAN), dichloroacetone, trichloronitromethane (TCNM), and trichloroacetone. Solution pH significantly affected the formation and distribution of DBPs. CF was the most formed carbonated DBP (C-DBP) with the maximum of 217.9 μg/L at pH 8, and its formation was significantly higher in alkaline conditions. For nitrogenated DBPs (N-DBPs), the yields of DCAN and TCAN were significantly higher in acidic conditions, while the maximum of TCNM achieved in neutral conditions. Because the toxicity of N-DBPs is higher than that of C-DBPs, the pH should be controlled in neutral or slight alkaline conditions during prometryn chlorination to effectively control DBP formation and reduce the related toxicity.
- Subjects :
- Environmental Engineering
Halogenation
Health, Toxicology and Mutagenesis
0208 environmental biotechnology
Kinetics
chemistry.chemical_element
02 engineering and technology
010501 environmental sciences
01 natural sciences
Water Purification
chemistry.chemical_compound
Reaction rate constant
Bromide
Chlorine
Environmental Chemistry
Ammonium
0105 earth and related environmental sciences
Trichloroacetonitrile
Chloroform
Aqueous solution
Public Health, Environmental and Occupational Health
General Medicine
General Chemistry
Pollution
020801 environmental engineering
Disinfection
chemistry
Prometryne
Water Pollutants, Chemical
Disinfectants
Nuclear chemistry
Subjects
Details
- ISSN :
- 00456535
- Volume :
- 276
- Database :
- OpenAIRE
- Journal :
- Chemosphere
- Accession number :
- edsair.doi.dedup.....6631b08bfce889acfe1794444f191aeb