EDTA enhanced degradation of 4-bromophenol by Al super(0)-Fe super(0)-O sub(2) system

An EDTA enhanced bimetallic Al super(0)-Fe super(0)/O sub(2) process was proposed for spontaneous in situ production of H sub(2)O sub(2) and super(radical dot)OH to rapidly oxidize 4-bromophenol. The effects of EDTA on Al super(0)/O sub(2), Fe super(0)/O sub(2) and Al super(0)-Fe super(0)/O sub(2) s...

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Bibliographic Details
Published in:Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2015-03, Vol.263, p.71-82
Main Authors: Fan, Jin-Hong, Liu, Xin, Ma, Lu-ming
Format: Article
Language:English
Subjects:
Bimetals
Degradation
EDTA
Mass ratios
Methyl alcohol
Pathways
Radicals
Robustness
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Summary:An EDTA enhanced bimetallic Al super(0)-Fe super(0)/O sub(2) process was proposed for spontaneous in situ production of H sub(2)O sub(2) and super(radical dot)OH to rapidly oxidize 4-bromophenol. The effects of EDTA on Al super(0)/O sub(2), Fe super(0)/O sub(2) and Al super(0)-Fe super(0)/O sub(2) system were investigated. The mass ratio of Al super(0) and Fe super(0) was also optimized. The role of EDTA enhanced in situ production of super(radical dot)OH was verified by the addition of methanol and benzoic acid as super(radical dot)OH scavenger and the detection of para-hydroxybenzoic acid. Moreover, the degradation pathway of 4-bromophenol in Al super(0)-Fe super(0)/O sub(2) system was analyzed by the verification of reaction intermediates and Br super(-) concentration. And the robustness of EDTA enhanced bimetallic Al super(0)-Fe super(0)/O sub(2) process was also investigated. The results showed the EDTA enhanced effect may be attributed to the complex formed by EDTA and Fe(II) rather than Al(III). The EDTA enhanced Al super(0)-Fe super(0)/O sub(2) process exhibited higher reactivity than Al super(0)/O sub(2), Al super(0) + EDTA/O sub(2), Fe super(0)/O sub(2) and Fe super(0) + EDTA/O sub(2) process. 50 mg L super(-1) of 4-bromophenol could be completely degraded in 1 h with the 1:1 mass ratio of Al super(0) and Fe super(0). Accordingly, 4-bromophenol was attacked by super(radical dot)OH to achieve complete de-bromine and low molecular weight organic acids, even mineralized. The degradation pathway of 4-bromophenol in EDTA enhanced Al super(0)-Fe super(0)/O sub(2) may follow 4-bromocatechol and hydroquinone pathway.
ISSN:1385-8947
DOI:10.1016/j.cej.2014.10.082