Experimental Design Approach with Response Surface Methodology for Removal of Indigo Dye by Electrocoagulation

Abstract

Treatment of Indigo dye (leuco form), reduced in the industrial conditions of the SITEX (Textile Industrial Company), by a batch electrocoagulation using aluminum electrodes. Response Surface Methodology (RSM) and Box-Behnken design were used to optimize for Color Removal (CR(%)). Our results showed that the quadratic second order equation provided the best correlation for the decolorization of Indigo dye (CR(%)). On the other hand, the ANOVA analysis proved the large interaction between the current intensity and the initial concentration of the dye. Experiments were conducted to find the desired conditions for removal of particular concentration of the dye and lower Operation Cost. The results showed that CR(%) = 88.3% (R2) of color removal for initial dye concentration of 12.31 mg/l, with a current density of 2.81 A/m2, solution concentration of NaCl of 2.67 g/l. Under these conditions, Electrical Energy Consumption (EEC) and Electrode Consumption (EMC) and Operation Cost were 0.01999 kWh/m3 (R2 = 93.1%), 0.00142768 Kg/m3 (R2 = 79.4%) and 0.000558 US$/m3, respectively.