Combustion of textile monoazo, diazo and triazo dyes by solar photoelectro-Fenton: Decolorization, kinetics and degradation routes

Sergio GARCIA SEGURA, Enric Brillas

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

The viability of the electrochemical combustion of the monoazo Acid Orange 7, the diazo Acid Red 151 and the triazo Disperse Blue 71 by solar photoelectro-Fenton (SPEF) has been demonstrated. Comparative trials were made by electrolyzing 10L of 50mgL-1 of dissolved organic carbon of each azo dye in 0.05M Na2SO4 with 0.50 mM Fe2+ of pH 3.0 using a solar flow plant equipped with a Pt/air-diffusion filter-press cell coupled to a CPC photoreactor. Organics are oxidized by OH radicals formed from water oxidation at the Pt anode and in the bulk from the Fenton's reaction between Fe2+ and H2O2 generated at the cathode, whereas the mineralization was enhanced by the photolysis of intermediates by UV light from sunlight that irradiates the CPC photoreactor. The decay of all the azo dyes was followed by reversed-phase HPLC and always obeyed a pseudo-first-order reaction, being more rapid than the decolorization of the corresponding solutions due to the formation of colored products. The mineralization rate decreased in the order Acid Orange 7>Disperse Blue 71> Acid Red 151. Up to 97% mineralization was achieved for the former compound, remaining short-linear carboxylic acids in the final solution. In contrast, 90-92% mineralization was reached for the other two azo dyes and their final solutions contained undetected products more recalcitrant than carboxylic acids. The effect of current density on each degradation process was examined. Similar results were found using either a power supply or a photovoltaic panel to provide the same current density to the cell, corroborating the use of autonomous solar flow plants for SPEF. Aromatic products and hydroxylated derivatives were identified by LCMS and short-linear carboxylic acids were quantified by ion-exclusion HPLC. The formation of SO42-, NO3- and NH4+ ions, along with the loss of volatile N-products, was confirmed by ion chromatography.

Original languageEnglish (US)
Pages (from-to)681-691
Number of pages11
JournalApplied Catalysis B: Environmental
Volume181
DOIs
StatePublished - Feb 1 2016
Externally publishedYes

Fingerprint

Azo Compounds
Carboxylic Acids
Azo dyes
dye
Textiles
Coloring Agents
carboxylic acid
Dyes
combustion
Carboxylic acids
mineralization
Degradation
kinetics
degradation
Kinetics
Acids
acid
Current density
Ions
Ion chromatography

Keywords

  • Acid Orange 7
  • Acid Red 151
  • Disperse Blue 71
  • Solar photoelectro-Fenton
  • Water treatment

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

Cite this

@article{144c96ba9e4e451e9f2fdacaa86b7e22,
title = "Combustion of textile monoazo, diazo and triazo dyes by solar photoelectro-Fenton: Decolorization, kinetics and degradation routes",
abstract = "The viability of the electrochemical combustion of the monoazo Acid Orange 7, the diazo Acid Red 151 and the triazo Disperse Blue 71 by solar photoelectro-Fenton (SPEF) has been demonstrated. Comparative trials were made by electrolyzing 10L of 50mgL-1 of dissolved organic carbon of each azo dye in 0.05M Na2SO4 with 0.50 mM Fe2+ of pH 3.0 using a solar flow plant equipped with a Pt/air-diffusion filter-press cell coupled to a CPC photoreactor. Organics are oxidized by OH radicals formed from water oxidation at the Pt anode and in the bulk from the Fenton's reaction between Fe2+ and H2O2 generated at the cathode, whereas the mineralization was enhanced by the photolysis of intermediates by UV light from sunlight that irradiates the CPC photoreactor. The decay of all the azo dyes was followed by reversed-phase HPLC and always obeyed a pseudo-first-order reaction, being more rapid than the decolorization of the corresponding solutions due to the formation of colored products. The mineralization rate decreased in the order Acid Orange 7>Disperse Blue 71> Acid Red 151. Up to 97{\%} mineralization was achieved for the former compound, remaining short-linear carboxylic acids in the final solution. In contrast, 90-92{\%} mineralization was reached for the other two azo dyes and their final solutions contained undetected products more recalcitrant than carboxylic acids. The effect of current density on each degradation process was examined. Similar results were found using either a power supply or a photovoltaic panel to provide the same current density to the cell, corroborating the use of autonomous solar flow plants for SPEF. Aromatic products and hydroxylated derivatives were identified by LCMS and short-linear carboxylic acids were quantified by ion-exclusion HPLC. The formation of SO42-, NO3- and NH4+ ions, along with the loss of volatile N-products, was confirmed by ion chromatography.",
keywords = "Acid Orange 7, Acid Red 151, Disperse Blue 71, Solar photoelectro-Fenton, Water treatment",
author = "{GARCIA SEGURA}, Sergio and Enric Brillas",
year = "2016",
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day = "1",
doi = "10.1016/j.apcatb.2015.08.042",
language = "English (US)",
volume = "181",
pages = "681--691",
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TY - JOUR

T1 - Combustion of textile monoazo, diazo and triazo dyes by solar photoelectro-Fenton

T2 - Decolorization, kinetics and degradation routes

AU - GARCIA SEGURA, Sergio

AU - Brillas, Enric

PY - 2016/2/1

Y1 - 2016/2/1

N2 - The viability of the electrochemical combustion of the monoazo Acid Orange 7, the diazo Acid Red 151 and the triazo Disperse Blue 71 by solar photoelectro-Fenton (SPEF) has been demonstrated. Comparative trials were made by electrolyzing 10L of 50mgL-1 of dissolved organic carbon of each azo dye in 0.05M Na2SO4 with 0.50 mM Fe2+ of pH 3.0 using a solar flow plant equipped with a Pt/air-diffusion filter-press cell coupled to a CPC photoreactor. Organics are oxidized by OH radicals formed from water oxidation at the Pt anode and in the bulk from the Fenton's reaction between Fe2+ and H2O2 generated at the cathode, whereas the mineralization was enhanced by the photolysis of intermediates by UV light from sunlight that irradiates the CPC photoreactor. The decay of all the azo dyes was followed by reversed-phase HPLC and always obeyed a pseudo-first-order reaction, being more rapid than the decolorization of the corresponding solutions due to the formation of colored products. The mineralization rate decreased in the order Acid Orange 7>Disperse Blue 71> Acid Red 151. Up to 97% mineralization was achieved for the former compound, remaining short-linear carboxylic acids in the final solution. In contrast, 90-92% mineralization was reached for the other two azo dyes and their final solutions contained undetected products more recalcitrant than carboxylic acids. The effect of current density on each degradation process was examined. Similar results were found using either a power supply or a photovoltaic panel to provide the same current density to the cell, corroborating the use of autonomous solar flow plants for SPEF. Aromatic products and hydroxylated derivatives were identified by LCMS and short-linear carboxylic acids were quantified by ion-exclusion HPLC. The formation of SO42-, NO3- and NH4+ ions, along with the loss of volatile N-products, was confirmed by ion chromatography.

AB - The viability of the electrochemical combustion of the monoazo Acid Orange 7, the diazo Acid Red 151 and the triazo Disperse Blue 71 by solar photoelectro-Fenton (SPEF) has been demonstrated. Comparative trials were made by electrolyzing 10L of 50mgL-1 of dissolved organic carbon of each azo dye in 0.05M Na2SO4 with 0.50 mM Fe2+ of pH 3.0 using a solar flow plant equipped with a Pt/air-diffusion filter-press cell coupled to a CPC photoreactor. Organics are oxidized by OH radicals formed from water oxidation at the Pt anode and in the bulk from the Fenton's reaction between Fe2+ and H2O2 generated at the cathode, whereas the mineralization was enhanced by the photolysis of intermediates by UV light from sunlight that irradiates the CPC photoreactor. The decay of all the azo dyes was followed by reversed-phase HPLC and always obeyed a pseudo-first-order reaction, being more rapid than the decolorization of the corresponding solutions due to the formation of colored products. The mineralization rate decreased in the order Acid Orange 7>Disperse Blue 71> Acid Red 151. Up to 97% mineralization was achieved for the former compound, remaining short-linear carboxylic acids in the final solution. In contrast, 90-92% mineralization was reached for the other two azo dyes and their final solutions contained undetected products more recalcitrant than carboxylic acids. The effect of current density on each degradation process was examined. Similar results were found using either a power supply or a photovoltaic panel to provide the same current density to the cell, corroborating the use of autonomous solar flow plants for SPEF. Aromatic products and hydroxylated derivatives were identified by LCMS and short-linear carboxylic acids were quantified by ion-exclusion HPLC. The formation of SO42-, NO3- and NH4+ ions, along with the loss of volatile N-products, was confirmed by ion chromatography.

KW - Acid Orange 7

KW - Acid Red 151

KW - Disperse Blue 71

KW - Solar photoelectro-Fenton

KW - Water treatment

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