Photocatalytic degradation of 2,4,6-tribromophenol over Fe-doped ZnIn2S4: Stable activity and enhanced debromination

Authors: Bo Gao, Lifen Liu, Jiadong Liu, Fenglin Yang

Abstract:
Fe doped ZnIn₂S₄ catalyst was prepared and tested for photocatalytic degradation of 2,4,6- tribromophenol (2,4,6-TBP), it was more efficient in debromination and total organic carbon (TOC) removal, compared with TiO₂ (P25) and ZnIn₂S₄. The preparation of Fe-ZnIn2S4 involved a facile hydrothermal ZnIn2S4 synthesis process at low temperature and without templates, followed by chemical reductive deposition of Fe. The catalysts were characterized using scanning electron microscopy (SEM) equipped with an X-ray energy dispersive spectroscopy (EDS), TEM and HRTEM, FT-IR spectra, X-ray diffraction (XRD) and UV–vis diffuse reflectance spectra. The band gaps of ZnIn₂S₄ and Fe-ZnIn₂S₄ calculated from the onset of the absorption edges were 2.12 eV and 2.05 eV, respectively. The calculated pseudo-first-order constants (Kr) were in the order of TiO₂ (0.022 min−1) < 0.5 wt% FeTiO₂ (0.0369 min−1) < ZnIn₂S₄ (0.362 min−1) < 0.5 wt% Fe-ZnIn2S4 (0.436 min−1). After 1 h reaction by Fe-ZnIn₂S₄, the released bromide concentration was 17.6mg l −1, which was 1.11 and 2.69 times higher than ZnIn₂S₄ and TiO₂ (P25), respectively. The increase in TOC removal was 7% and 33% compared to ZnIn2S4 and TiO₂ (P25), respectively. The repeated tests proved that the synthesized Fe-ZnIn2S4 was stable, reusable and durable in degradation of 2,4,6-TBP. The possible cycle of iron species and a tentative debromination pathway were proposed.

Keywords:
Zerovalent iron nanoparticles
Band gap
Photocatalysis
LC MS

Published in: Applied catalysis B: Environmental  (Volume 129, Pages 1-614, 17 January 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Photocatalytic degradation of 2,4,6-tribromophenol over Fe-doped ZnIn2S4: Stable activity and enhanced debromination

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