Combining fluidized metal-impregnated granular activated carbon in three-dimensional electrocoagulation system: Feasibility and optimization test of color and COD removal from real cotton textile wastewater

The present study focused on the treatment of real cotton textile wastewater by combining metal (Al/Fe)-impregnated granular activated carbon (MIGAC) as moving particle electrodes in electrocoagulation, referred to here as the MIGAC-TEC system. The feasibility test clearly indicated that MIGAC significantly accelerated the decolorization and COD removal efficiency. The effects of four parameters: applied voltage, initial pH, MIGAC dosage, and reaction time on the percentage of color and COD removal were investigated using response surface methodology with a central composite design. As results, it was found that the decolorization (R-2 = 0.9576) and COD removal (R2 = 0.9395) were well fitted by a developed quadratic polynomial models and the initial pH was the most influential factor. Through numerical optimization, highly acceptable removal performances of 99.13 +/- 0.21% decolorization and 97.01 +/- 0.18% COD removal efficiency were achieved under statistically optimized conditions, and suggested that the developed system is a very suitable technique for the enhancement of electrocoagulation-based cotton textile wastewater treatment. (C) 2015 Elsevier B.V. All rights reserved.