Photocatalytic Degradation of Direct Red 23 and Direct Brown 166 Azo Dyes Using Polyoxometalate-Titanium Dioxide Nanocomposite

Document Type : Original Article

Authors

1 Department of Chemistry, Faculty of Sciences, University of Hormozgan, Bandar Abbas 71961, Iran

2 Department of Chemistry, Marvdasht Branch, Islamic Azad University, Marvdasht , Iran

Abstract

In this study, the polyoxometalate-titanium dioxide nanocomposite (SiW11-TiO2) was synthesized using the hydrothermal method and characterized by FT-IR, XRD, FE-SEM/EDS, BET, and TEM techniques. The performance of this nanocomposite as a nanophotocatalyst was then investigated for the degradation of the dyes DR 23 and DB 166 under various conditions, including irradiation time, photocatalyst dosage, dye solution concentration, and pH, under visible light from a sodium lamp and sunlight. The results demonstrated that this photocatalyst, using only 10 mg at acidic pH and within 30 minutes, could significantly degrade these dyes, with a marked increase in degradation efficiency under sunlight. The kinetic study of the degradation reaction indicated that the process follows pseudo-first-order kinetics. Additionally, experimental results revealed that the SiW11-TiO2 nanocomposite exhibited superior photocatalytic activity compared to SiW11 alone. This nanocomposite not only has the capability to completely degrade azo dyes but also demonstrated stability and reusability up to 12 cycles and effective performance in real sample applications.

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