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Solar-light-induced photocatalytic decomposition of two azo dyes on new TiO2 photocatalyst containing nitrogen

Paper ID Volume ID Publish Year Pages File Format Full-Text
49132 46552 2006 9 PDF Available
Title
Solar-light-induced photocatalytic decomposition of two azo dyes on new TiO2 photocatalyst containing nitrogen
Abstract

The photocatalytic decolourisation of two azo dyes—Reactive Red 198 and Direct Green 99—in an aqueous solution by the artificial visible light radiation was investigated. The industrial metatitanic acid (H2TiO3) obtained directly from the sulphate technology installation was N-doped and used as photocatalyst. H2TiO3 was calcinated at different temperatures, ranging from 300 to 500 °C, for 4 or 20 h, respectively, in an ammonia atmosphere. The UV–vis/DR spectra of the modified catalysts exhibited an additional maximum in the vis region (λ ≈ 476.8 nm, EG = 2.60 eV for catalysts calcinated for 4 h and λ ≈ 479.5 nm, EG = 2.59 eV for catalysts calcinated for 20 h, which may be due to the presence of nitrogen in TiO2 particles. The chemical structure of the modified photocatalysts was investigated using FTIR/DRS spectroscopy and the presence of nitrogen was confirmed. A photocatalytic activity of the investigated catalysts was determined on the basis of a decomposition rate of azo dyes. The decomposition of Reactive Red 99 increased with increasing the calcination temperature of photocatalysts, whereas the activity of the prepared photocatalysts towards Direct Green 198 degradation was as follows: 300–20 h < 400–20 h < 500–20 h < 300–4h < 400–4 h < 500–4 h. Both, the calcination time and temperature had no influence on the amount of nitrogen-doped into TiO2 structure. The inversely proportional linear dependence between the decomposition rates of azo dyes and the intensity of the band attributed to the hydroxyl groups for both dissociated water and molecularly adsorbed water was observed. With increasing temperature of calcinations, the amount of the hydroxyl groups decreased, whereas the decomposition of azo dyes increased.

Keywords
Visible light active photocatalyst; The industrial precursor; Nitrogen-doped; Ammonia; Titanium dioxide; Azo dye; Reactive Red; Direct Green
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Solar-light-induced photocatalytic decomposition of two azo dyes on new TiO2 photocatalyst containing nitrogen
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 62, Issues 1–2, 10 January 2006, Pages 150–158
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us