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Kinetic study of the manganese‐based catalytic hydrogen peroxide oxidation of a persistent azo‐dye
Author(s) -
Tizaoui Chedly,
Karodia Nazira,
Aburowais Mohsen
Publication year - 2010
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2293
Subject(s) - catalysis , hydrogen peroxide , chemistry , manganese , kinetics , reaction rate constant , redox , degradation (telecommunications) , reaction rate , oxidation process , kinetic energy , order of reaction , nuclear chemistry , photochemistry , inorganic chemistry , chemical engineering , organic chemistry , telecommunications , physics , quantum mechanics , computer science , engineering
Abstract BACKGROUND: The discharge of synthetic dyes by the textile industry into the environment poses concerns due to their persistence and toxicity. New efficient treatment processes are required to effectively degrade these dyes. The aim of this work was to study the degradation of a persistent dye (Drimarene Brilliant Reactive Red K‐4BL, C.I.147) using H 2 O 2 oxidation catalysed by an Mn(III)‐saltren catalyst and to develop a kinetic model for this system. RESULTS: Dye oxidation with H 2 O 2 was significantly improved by the addition of the catalyst. As the pH was increased from 3 to 10, the oxidation rates increased significantly. The kinetic model developed in this study was found to adequately explain the experimental results. In particular, dye oxidation can be described at high pH by pseudo‐first‐order kinetics. A Michaelis–Menton type equation was developed from the model and was found to adequately describe the effect of H 2 O 2 and catalyst concentrations on the apparent pseudo‐first‐order rate constant. Optimum catalyst and H 2 O 2 concentrations of 500 mg L −1 and 6.3 g L −1 , respectively, were found to give maximum reaction rates. CONCLUSION: Catalytic H 2 O 2 oxidation was found to be effective for the removal of persistent dye and the results obtained in this work are of significance for design and scale‐up of a treatment process. Copyright © 2009 Society of Chemical Industry