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Effect of inorganic oxidants in photodecolourization of an azo dye

Paper ID Volume ID Publish Year Pages File Format Full-Text
29240 44137 2007 6 PDF Available
Title
Effect of inorganic oxidants in photodecolourization of an azo dye
Abstract

Aqueous solutions of the dye Acid Orange 7 were decolourized in the presence of ultraviolet irradiation (UV) and photocatalyst, TiO2. Decolourization rate was increased in the presence of UV/TiO2 compared to UV alone. Addition of hydrogen peroxide, H2O2, in concentrations ranging from 8.82 × 10−3 to 7.1 × 10−2 M to the solution containing pollutant and TiO2 (0.5 g l−1) resulted in increased rates of decolourization. The rate of dye decolourization using periodate, NaIO4, (4.76 × 10−5 to 1 × 10−3 M) at TiO2 concentration of 0.5 g l−1 under UV illumination was higher than that for UV/TiO2/H2O2 and increases with periodate concentration. The rate of decolourization of Acid Orange 7 was found to follow first-order kinetics. Reaction rate orders with respect to the oxidant species were 0.51 and 0.8, respectively for H2O2 and NaIO4. Kinetic parameters of the photodecolourization process such as apparent rate constant (kapp) and initial reaction rate (Rinitial) and efficiency parameters such as apparent quantum yield (Qapp) and electrical energy per order (EE/O) were estimated and compared for UV/TiO2, UV/TiO2/H2O2 and UV/TiO2/IO4− catalytic systems.

Keywords
Decolourization; Dyes; Titanium dioxide; Hydrogen peroxide; Sodium periodate; Apparent quantum yield; Electrical energy per order
First Page Preview
Effect of inorganic oxidants in photodecolourization of an azo dye
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 191, Issues 2–3, 25 September 2007, Pages 132–137
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering