A new high efficiency visible-light photocatalyst made of SnS2 andconjugatedderivative ofpolyvinyl alcoholand its application to Cr(VI) reduction

Fen Zhang a, Yongcai Zhang a,*, Chuanqiang Zhou b, Zhanjun Yang a, Huaiguo Xue a, Dionysios D. Dionysiou c,*

aSchool of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225009, China

bTesting Center, Yangzhou University, Yangzhou 225009, China

cEnvironmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA

ABSTRACT

This study focuses on the synthesis of a new high efficiency visible-light photocatalyst made of SnS2 and conjugated derivative (CPVA)from thermal dehydration of polyvinyl alcohol (PVA), and the evaluation of its performance in photocatalytic reduction of aqueous Cr(VI). SnS2/CPVA nanocomposites were synthesized via the procedures of (i) mixing of SnS2 nanocrystals and PVA in aqueous solution andevaporation ofthe aqueous solvent to generate SnS2/PVA nanocomposites, and (ii) thermal treatment of the SnS2/PVA nanocomposites for transforming their PVA into conjugated CPVA. The optimum conditions for synthesis of most efficient SnS2/CPVA nanocomposite were explored. The characterization by X-ray diffraction, Raman spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy and elemental mapping indicated the formation of SnS2/CPVA nanocomposites. The photocatalytic experiments showed that SnS2/CPVA nanocomposite synthesized under the optimum conditions (SnS2/CPVA-1%-180°C-2h) had exceptionally higher photocatalytic activity than SnS2 nanocrystals, physical mixture of SnS2 nanocrystals and CPVA, SnS2/CPVC nanocomposite and TiO2/CPVA nanocomposite in the reduction of aqueous Cr(VI) undervisible-light (wavelength>420 nm) irradiation. The mechanismunderlying the most enhanced photocatalytic activity ofSnS2/CPVA-1%-180°C-2h was elucidated,based upon comparison between theoptical, photoelectric and electrochemical impedanceproperties of SnS2 nanocrystals and different SnS2/CPVA nanocomposites. Furthermore, the effects of photocatalytic experiment parameters (including dosage of photocatalyst, and initial pH and concentration of Cr(VI) aqueous solution) on the Cr(VI) removal efficiency by SnS2/CPVA-1%-180°C-2h were also studied.

Keywords:Tin disulfide; Polyvinyl alcohol; Nanocomposites; Photocatalytic; Cr(VI) reduction

Chemical Engineering Journal, 2017, 324: 140-153. SCI IF = 5.3

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