Fabrication of Zr-doped TiO2/chitosan composite catalysts with enhanced visible-light-mediated photoactivity for the degradation of Orange II dye
Author(s) -
Pelin Demirçivi,
Esra Bilgin Şimşek
Publication year - 2018
Publication title -
water science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.406
H-Index - 137
eISSN - 1996-9732
pISSN - 0273-1223
DOI - 10.2166/wst.2018.298
Subject(s) - photocatalysis , materials science , anatase , catalysis , x ray photoelectron spectroscopy , nuclear chemistry , fourier transform infrared spectroscopy , composite number , methyl orange , crystallinity , zirconium , chemical engineering , chemistry , composite material , organic chemistry , metallurgy , engineering
Zirconium/titanium/chitosan (Zr/Ti/CHT) composite catalysts were synthesized by sol-gel method using different chitosan amounts (5-20 wt.%) and their activity in the photocatalytic degradation of Orange II dye was evaluated for the first time. The results were compared with Zr/Ti, Zr/CHT and Ti/CHT catalysts. The composite catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy analysis. XRD analysis revealed that the Zr/Ti/CHT composite catalyst showed high crystallinity of anatase TiO 2 phase. Photocatalytic experiments showed that adding CHT into the catalyst structure increased the photocatalytic degradation under visible light irradiation. Also, the first-order reaction rate constant, k app , was calculated using the Langmuir-Hinshelwood (L-H) equation. The k app values were found to be 0.009, 0.0013, 0.012 and 0.014 min -1 for Zr/Ti, Zr/CHT, Ti/CHT and Zr/Ti/CHT, respectively. According to stability tests, after the first cycle Orange II dye degradation was found to be 95%, while it was 37% after the fifth cycle. The results showed that the composite catalyst could be used several times for Orange II dye degradation.
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