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Sci Total Environ. 2016 Aug 15;562:889-897. doi: 10.1016/j.scitotenv.2016.04.093. Epub 2016 Apr 24.

Reaction pathway and oxidation mechanisms of dibutyl phthalate by persulfate activated with zero-valent iron.

Author information

1
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, China, Guangzhou 510640, PR China.
2
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, China, Guangzhou 510640, PR China; State Key Lab Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China. Electronic address: ppjqwan@scut.edu.cn.
3
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, China, Guangzhou 510640, PR China; State Key Lab Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China.

Abstract

This study investigated reaction pathway and oxidation mechanisms of dibutyl phthalate (DBP) by persulfate (PS) activated with zero-valent iron (ZVI). The DBP degradation was studied at three pH values (acidic, neutral and basic) in the presence of different organic scavengers. Using a chemical probe method, both sulfate radical (SO4(-)) and hydroxyl radical (·OH) were found to be primary oxidants at pH3.0 and pH7.0, respectively while ·OH was the major specie to oxidize DBP at pH11.0. A similar result was found in an experiment of Electron Spin Resonance spin-trapping where in addition to OH, superoxide radical (O2(-)) was detected at pH11.0. The transformation of degradation products including dimethyl phthalate (DMP), diethyl phthalate (DEP), phthalic anhydride, and acetophenone exhibited diverse variation during the reaction processes. The phthalic anhydride concentration appeared to be maximum at all pHs. Another eleven intermediate products were also found at pH3.0 by GC-MS and HPLC analysis, and their degradation mechanisms and pathways were proposed. It was suggested that dealkylation, hydroxylation, decarboxylation and hydrogen extraction were the dominant degradation mechanisms of DBP at pH3.0.

KEYWORDS:

Degradation pathway; Dibutyl phthalate (DBP); Mechanism; Persulfate (PS); Zero-valent iron

PMID:
27125682
DOI:
10.1016/j.scitotenv.2016.04.093
[Indexed for MEDLINE]

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