Abstract
Decolorization of Acid Blue 161 (AB161) by solid peroxides such as CaO2 and Na2O2 catalyzed by iron in aqueous solution was investigated. The effect of initial pH, concentration of H2O2, Fe2+, and AB161 on the decolorization kinetics was investigated and compared with the results by liquid H2O2. The experimental results show that decolorization of AB161 follows the second-order kinetic. The second decolorization rate constants and oxidation efficiency at different initial pH, Fe2+, H2O2, and AB161 concentration were correlated with dimensionless ratios such as H2O2/Fe2+ or H2O2/AB161. About two dozens of correlation equations are developed in this paper to quantify the effect of the variables on the decolorization rate constants of AB161. Among solid peroxides such as CaO2 and Na2O2 and liquid H2O2, the optimal pH and [Fe2+] are 2.5 and 5.0 × 10−4 mol L−1, while the concentration of CaO2, Na2O2, and H2O2 is 0.30, 0.25 g L−1 and 3.1 × 10−3 mol L−1, respectively. Our experimental results show that decolorization kinetics of AB161 using liquid H2O2 is faster than that using CaO2 and Na2O2 catalyzed by Fe2+, while decolorization rate of AB161 by CaO2 is slightly faster than that by Na2O2 due to the fact that the CaO2 is a fine powder of an average diameter of 0.74 mm and Na2O2 is a particle with an average diameter of 1 mm. Regardless of the solid or liquid peroxide forms, e.g. CaO2, Na2O2, or liquid H2O2, the optimal molar ratio H2O2/Fe2+ of 12 obtained experimentally agreed reasonably with the theoretical predicted value of 11. In addition, the decolorization efficiency, η, is also not affected by the form of peroxides and decreases with the H2O2/AB161 when H2O2, Fe2+, and pH were fixed at 3.1 × 10−3, 5.0 × 10−4 mol L−1, and 2.5, respectively.
Original language | English |
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Pages (from-to) | 19344-19356 |
Number of pages | 13 |
Journal | Desalination and Water Treatment |
Volume | 57 |
Issue number | 41 |
DOIs | |
Publication status | Published - 1 Sept 2016 |
Externally published | Yes |
Keywords
- Advanced oxidation processes
- Azo dye
- CaO
- Fenton
- Liquid HO
- NaO
ASJC Scopus subject areas
- Water Science and Technology
- Ocean Engineering
- Pollution