Enhanced debromination of 4-bromophenol by the UV/sulfite process: Efficiency and mechanism
Autor: | Bihuang Xie, Huang Xianfeng, Weiming Zhang, Zhe Xu, Xuchun Li, Bingcai Pan |
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Rok vydání: | 2017 |
Předmět: |
Environmental Engineering
Halogenation Ultraviolet Rays Kinetics Inorganic chemistry 02 engineering and technology 010501 environmental sciences Mass spectrometry Solvated electron Photochemistry 01 natural sciences chemistry.chemical_compound Phenols Sulfite Sulfite process Sulfites Environmental Chemistry Flame Retardants 0105 earth and related environmental sciences General Environmental Science Chemistry Photodissociation General Medicine 021001 nanoscience & nanotechnology Models Chemical Degradation (geology) 0210 nano-technology |
Zdroj: | Journal of Environmental Sciences. 54:231-238 |
ISSN: | 1001-0742 |
Popis: | Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we systematically studied the debromination efficiency and mechanism of para-bromophenol (4-BP) by a recently developed UV/sulfite process. 4-BP underwent rapid degradation with the kinetics accelerated with the increasing sulfite concentration, pH (6.1–10) and temperature, whereas inhibited by dissolved oxygen and organic solvents. The apparent activation energy was estimated to be 27.8 kJ/mol. The degradation mechanism and pathways of 4-BP were explored by employing N2O and nitrate as the electron scavengers and liquid chromatography/mass spectrometry to identify the intermediates. 4-BP degradation proceeded via at least two pathways including direct photolysis and hydrated electron-induced debromination. The contributions of both pathways were distinguished by quantifying the quantum yields of 4-BP via direct photolysis and hydrated electron production in the system. 4-BP could be readily completely debrominated with all the substituted Br released as Br−, and the degradation pathways were also proposed. This study would shed new light on the efficient dehalogenation of brominated aromatics by using the UV/sulfite process. |
Databáze: | OpenAIRE |
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