1. Role of eaq⁻, ·OH and H· in radiolytic degradation of atrazine: a kinetic and mechanistic approach.
- Author
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Khan JA, Shah NS, Nawaz S, Ismail M, Rehman F, and Khan HM
- Subjects
- Gas Chromatography-Mass Spectrometry, Hydrogen-Ion Concentration, Kinetics, Waste Disposal, Fluid, Water Pollutants, Chemical, Water Purification, X-Rays, Atrazine chemistry, Atrazine radiation effects, Herbicides chemistry, Herbicides radiation effects, Hydroxyl Radical chemistry, Protons
- Abstract
The degradation of atrazine was investigated in aqueous solution by gamma-ray irradiation. 8.11 μM initial atrazine concentration could be completely removed in N₂ saturated solution by applying 3500 Gy radiation dose at a dose rate of 296 Gy h(-1). Significant removal of atrazine (i.e., 39.4%) was observed at an absorbed dose of 1184 Gy in air saturated solution and the removal efficiency was promoted to 50.5 and 65.4% in the presence of N₂O and N₂ gases, respectively. The relative contributions of hydrated electron, hydroxyl radical and hydrogen radical toward atrazine degradation were determined as ratio of observed dose constant (kobs) and found to be 5: 3: 1 for keaq(-): k·OH: kH·, respectively. The degradation efficiency of atrazine was 69.5, 55.6 and 37.3% at pH 12.1, 1.7 and 5.7, respectively. A degradation mechanism was proposed based on the identified degradation by-products by gas chromatography-mass spectrometry. Taking the relative contributions of oxidative and reductive species to atrazine degradation into account, reductive pathway proved to be a better approach for the radiolytic treatment of atrazine contaminated water., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2015
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