Modeling and Optimization of Operating Parameters for Removal of Acid Red35 Dye from Reconstituted Waste Water by Electrocoagulation in an Internal Loop Airlift Reactor Using the Experimental Design

Abstract

In this study, we investigated the optimization of the treatment, in an internal loop airlift reactor (ILAL Reactor), by electrocoagulation (EC) to remove AcidRed35 (AR35) Dye from aqueous solutions using the Aluminum anode, and taking into account many factors such as electric conductivity, applied voltage, the treatment time and the inter-electrode distance Dint.

To verify these factors and their effects on the (EC) of (AR35), we have established a model following the Methodology of Experimental Design. The mathematical model is established, initially using a full screening plan, to verify the existence of the effect of these four factors, and in a second time, a central composite design (CCD) is applied [1]. The model describes the change in measured responses, of dye removal efficiency (R (%)), and energy consumption (E cons (W h/m³)), according to the three factors (the conductivity, the treatment time and the inter-electrode distance (Dint)). The voltage was fixed at 9 V because, it have no effect on the removal efficiency of (AR35) during the screening step.

The graphical representation of this model, in the variable space, and “desirability function” allowed us to define the optimal conditions for these parameters. The optimum value of the conductivity, the time, and Dint are respectively 1000 μs/m², 20 min and 1.5 cm. A 53% efficiency of dye removal is observed with an energy consumption of 1859 Wh/m³, and this optimal condition is confirmed experimentally for the two responses.