Optimization of material and energy consumption for removal of Acid Red 14 by simultaneous electrocoagulation and electroflotation

Decolorization of wastewater of industries which consume dye is an environmental priority. Electrocoagulation and electroflotation methods are appropriate for treatment of these wastewaters. This study investigates the effect of four parameters, electrical conductivity, current density, initial dye concentration, and initial pH, on the performance of a simultaneous electrocoagulation/electroflotation system for removal of Acid Red 14. The optimum values of these parameters were determined based on the amount of electrical energy and aluminum consumption and the best performance of coagulation and bubble generation. The optimum condition was revealed to be electrical conductivity = 1,600 μS/cm, current density = 60 mA/cm², initial dye concentration = 185 mg/L and initial pH = 7. After less than 180 min of electrolysis, 90% dye removal was achieved with a specific energy consumption = 102 kWh/kg dye_removed, anode dissolution = 2.09 kg Al/kg dye_removed and sludge total suspended solids = 15,050 mg/L. Liquid chromatography–UV–mass spectroscopy analyses were conducted on samples of raw and treated wastewater. Results showed that intermediate compounds formed from the breaking of the dye molecules. The advantages of this method are a low material and energy consumption. The amount of produced sludge was low; consequently sludge disposal and management costs would be reduced. This method should be used cautiously for treatment of textile wastewater due to the formation of intermediate compounds.