Comparative study of discoloration of mono-azo dye by catalytic oxidation based on wells-dawson heteropolyanion catalyst

The objective of this research was to study and compare the kinetic discoloration of mono azo dye Methyl Orange (MO) in aqueous solution by (H2O2) and (KMnO4) using a Wells-Dawson heteropolyanion (α2P2W17O61Cu)8−. The factors on the discoloration of methyl orange, such as initial pH of the aqueous solution, mass of the catalyst, concentration of the oxidants, initial dye concentration were investigated. The results reveal that the use of (α2P2W17Cu /H2O2) and (α2P2W17Cu /KMnO4) systems has a great activity in the discoloration of MO which can respectively reached 90,6 % and 9851%. However, the kinetic discoloration of MO by (α2P2W17Cu /KMnO4) system is more quickly than that of the system (α2P2W17Cu /H2O2); where the reaction time is respectively 60 min and 240 min. The kinetic parameters for both systems were also determined.