Factorial experimental design for the optimization of catalytic degradation of malachite green dye in aqueous solution by Fenton process

• Fenton process for the catalytic degradation of malachite green dye.
• Optimal conditions for better degradation were evaluated by experimental design.
• Proposed model correctly evaluates the effect of the investigated variables.
• Maximum degradation efficiency of 93.83% was obtained.

This work focuses on the optimization of the catalytic degradation of malachite green dye (MG) by Fenton process “Fe2+/H2O2”. A 24 full factorial experimental design was used to evaluate the effects of four factors considered in the optimization of the oxidative process: concentration of MG (X1), concentration of Fe2+ (X2), concentration of H2O2 (X3) and temperature (X4). Individual and interaction effects of the factors that influenced the percentage of dye degradation were tested. The effect of interactions between the four parameters shows that there is a dependency between concentration of MG and concentration of Fe2+; concentration of Fe2+ and concentration of H2O2, expressed by the great values of the coefficient of interaction. The analysis of variance proved that, the concentration of MG, the concentration of Fe2+ and the concentration of H2O2 have an influence on the catalytic degradation while it is not the case for the temperature. In the optimization, the great dependence between observed and predicted degradation efficiency, the correlation coefficient for the model (R2=0.986) and the important value of F-ratio proved the validity of the model. The optimum degradation efficiency of malachite green was 93.83%, when the operational parameters were malachite green concentration of 10 mg/L, Fe2+ concentration of 10 mM, H2O2 concentration of 25.6 mM and temperature of 40 °C.

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