Statistical Investigation in Conjunction with a Box–Behnken Design for the Removal of Dyes Using Electrocoagulation

In the present study, the decolorization of a solution containing four dyes––acid violet 17 (AV 17), malachite green (MG), methylene blue (MB), and Congo red (CR)––was performed using electrocoagulation (EC) with the help of aluminum electrodes. A Box–Behnken design with three factors––current, electrode spacing, and pH––was used to optimize the factors for greater dye removal efficiency. A reasonably good fit was obtained for acid (AV17 and CR) and basic (MG and MB) dye removal under optimized conditions (pH 5, electrode spacing 1 cm, and current 0.03 A/cm2). High coefficient-of-determination values was obtained for the acid and basic dyes (R2 = 0.979 and 0.977, respectively), implying a good fit for both regression models. Maxima of 76.6% and 73.8% dye removal were obtained under optimized conditions, confirming that the EC process is a viable option for dye removal.