Iron-Activated Persulfate Oxidation of an Azo Dye in Model Wastewater: Influence of Iron Activator Type on Process Optimization

The study explores the potential of iron-activated persulfate oxidation of an azo dye in model wastewater. The influence of the type of iron activator on process efficiency was investigated by using ferrous and zero valent iron. The Box-Behnken experimental design and response surface methodology were applied for the modeling of the Fe2+/S2O82- and Fe-0/S2O82- processes. The combined effect of three important process parameters was investigated and presented by the means of the quadratic polynomial model. The statistical analysis of model performance was evaluated by ANOVA. The optimal process conditions giving the maximal mineralization for both processes were determined: pH 4.81, [Fe2+] 1.64 mM, and [S2O82-] = 84.87 mM predicting 35.14% mineralization and pH 5.52; [Fe-0] = 4.27 mM and [S2O82-] = 138.43mM predicting 54.38% mineralization by the Fe2+/S2O82- and Fe-0/S2O82- processes, respectively. The predicted values of dye mineralization obtained by model equations were in good agreement with the experimental values. The type of iron activator was demonstrated to significantly influence both process efficiency and optimal conditions. DOI: 10.1061/(ASCE)EE.1943-7870.0000347. (C) 2011 American Society of Civil Engineers.