engleski

Iron activated persulfate oxidation of an azo dye in model wastewater: the influence of iron activator type and processes optimization

Azo compounds constitute the largest and the most diverse group of synthetic dyes and are widely used in a number of industries such as textile, food, cosmetics and paper printing. Due to the environmental protection and a current law regulations wastewater from dye production and dyehouses must be treated before discharge to the recipient. Over the last decade Advanced Oxidation Processes (AOPs) have acquired significant importance in degrading minute concentrations (ppb to ppm levels) of recalcitrant contaminants that are difficult to degrade using conventional water and gas treatment technologies. This study explores the potential of iron activated persulfate oxidation of an azo dye in model wastewater. The influence of the type of iron activator, ferrous and zero valent iron, on process efficiency was investigated. The Box-Behnken experimental design and response surface methodology were applied for the modeling of Fe2+/S2O82- and Fe0/S2O82- processes. The combined effect of three important process parameters was investigated and presented by the means of 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, [Fe0]=4.27 mM and [S2O82-]=138.43 mM predicting 54.38 % mineralization by Fe2+/S2O82- and Fe0/S2O82- processes, respectively. The predicted values of dye mineralization obtained by model equations were in a good agreement with the experimental values. It was demonstrated that the type of iron activator significantly influence on both process efficiency and optimal conditions determined.

dye wastewater; AOP; persulfate oxidation; iron activator; process parameters; response surface methodology

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