Synthesis of different crystallographic FeOOH catalysts for peroxymonosulfate activation towards organic matter degradation

In this study, different crystalline structures of FeOOH have been prepared. α-FeOOH was synthesized through a hydrothermal method, whereas β-FeOOH was synthesized a direct hydrolysis method. Moreover, γ- and δ-FeOOH were prepared by precipitation methods through slow and quick oxidation, respective...

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Bibliographic Details
Published in:RSC advances 2018-01, Vol.8 (13), p.7269-7279
Main Authors: Fan, Junyu, Zhao, Zhiwei, Ding, Zhaoxia, Liu, Jie
Format: Article
Language:English
Subjects:
Catalysis
Catalysts
Catalytic activity
Chemical synthesis
Chemistry
Crystal structure
Crystallinity
Crystallography
Decoloring
Degradation
Dyes
Electron paramagnetic resonance
Electron spin
Hydrothermal crystal growth
Hydroxyl groups
Leaching
Oxidation
Quenching
Radicals
Spin resonance
Surface area
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Summary:In this study, different crystalline structures of FeOOH have been prepared. α-FeOOH was synthesized through a hydrothermal method, whereas β-FeOOH was synthesized a direct hydrolysis method. Moreover, γ- and δ-FeOOH were prepared by precipitation methods through slow and quick oxidation, respectively. On this basis, their crystal structure, morphology, and surface area were measured. Then, all the synthesized materials were applied to activate peroxymonosulfate (PMS) to generate sulfate radicals (SO ˙) for acid orange 7(AO7) degradation. Compared with α-FeOOH, β-FeOOH, and γ-FeOOH, δ-FeOOH showed more efficient decolorization of AO7 in the catalytic system because of its abundant surface area and crystalline structure. The effects of several parameters in the δ-FeOOH/PMS/AO7 system were investigated. The results show that the initial pH, which is related to the features of surface hydroxyl groups, is the decisive factor, and excellent catalytic activity is maintained in the pH range 5-8. The increase of catalyst dosage and appropriate increase of PMS concentration contributed to promote the degradation effect. However, self-quenching was observed in a high PMS concentration system. Moreover, δ-FeOOH was stable after six consecutive cycles, and the leaching of iron ions was negligible. According to the quenching test and electron spin resonance analysis, both SO ˙ and ˙OH were the dominant radicals for AO7 degradation.
ISSN:2046-2069
2046-2069
DOI:10.1039/c7ra12615h