Photocatalytic Degradation of Azo Dye Reactive Violet 5 on Fe-Doped Titania Catalysts under Visible Light Irradiation

Antonio Zuorro,Giuseppina Iervolino,Vincenzo Vaiano,Marika Michela Monaco,Roberto Lavecchia

doi:10.3390/catal9080645

Antonio Zuorro, Giuseppina Iervolino + Show 3 more

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https://doi.org/10.3390/catal9080645

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Journal: Catalysts	Publication Date: Jul 29, 2019
Citations: 63	License type: CC BY 4.0

Affiliation: Sapienza University of Rome, University of Salerno

Abstract

The presence of azo dyes in textile effluents is an issue of major concern due to their potential impact on the environment and human health. In this study we investigate the photocatalytic degradation under visible light of Reactive Violet 5 (RV5), an azo dye widely used in the textile industry. A preliminary screening of different titania-based catalysts was carried out to identify the best candidate for RV5 removal. The selected catalyst was then tested in a stirred and aerated lab-scale reactor illuminated with a blue light-emitting diode (LED) source emitting in the wavelength range of 460–470 nm. The effects of pH, catalyst load, and hydrogen peroxide additions on the efficiency of dye removal were evaluated. Under the best conditions (pH 10, 3 g/L of catalyst, and 60 mM hydrogen peroxide), the dye solution was completely decolorized in about 2 h. Overall, the results obtained suggest that the proposed process may represent a suitable method for the removal of RV5 from textile effluents.

Highlights

IntroductionAzo dyes are the largest class of dyes used in industry [1]. These compounds are characterized by the presence of one or more azo bonds (–N=N–) in their molecule in association with one or more aromatic structures [2]
The results obtained suggest that the proposed process may represent a suitable method for the removal of Reactive Violet 5 (RV5) from textile effluents
Azo dyes are the largest class of dyes used in industry [1]

Summary

Introduction

Azo dyes are the largest class of dyes used in industry [1]. These compounds are characterized by the presence of one or more azo bonds (–N=N–) in their molecule in association with one or more aromatic structures [2]. The presence of azo dyes in textile effluents makes them harmful to the environment and to human health [5]. Their release into aquatic ecosystems may lead to a reduction of sunlight penetration and dissolved oxygen concentration, with deleterious effects on local flora and fauna [6]. Toxic and potentially carcinogenic compounds such as aromatic amines can be formed during dye degradation [7]. For these reasons, textile wastewater needs to be properly treated

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