Optimization of electrochemical oxidation of dye wastewater using response surface methodology

Abstract

A heteropolyacid iron phosphomolybdate (FePMo12) was synthesized with molybdophosphoric acid and ferric salt. Morphologies and microstructures were characterized by IR spectrometry and X-ray diffraction. The heteropolyanion showed a Keggin structure. Electrochemical oxidation of Acid Red 3R was investigated in the presence of FePMo12 supported on modified 4A molecular sieve as packing materials in the reactor. The decolorization efficiency was higher than that in two-dimension electrochemical cell. Box-Behnken design (BB) coupled with response surface methodology (RSM) was used to investigate the optimization of electrochemical degradation of dye wastewater. The relationship of electrolytic voltage, initial pH, air-flow and electrode span was quantitatively analyzed. A mathematical predictive model was established with the decolorization efficiency as response value. The results showed that the optimal technological conditions for decolorization of Acid Red 3R simulated wastewater were as follows: electrolytic voltage of 11.0 V; initial pH of 2; air-flow of 0.05 m3/h; electrode span of 3.0 cm. Under the optimized conditions, the decolorization efficiency reached 69.4% after 60 min. The calculated values of the model agreed well with the experimental data. The interaction of electrolytic voltage and initial pH, initial pH and air-flow had significant impacts on the response value by analysis of variance.