Abatement of Acid Orange 7 in macro and micro reactors. Effect of the electrocatalytic route

Abstract

The electrochemical treatment of aqueous solutions contaminated by Acid Orange 7 (AO7) was widely studied with the main objective to evaluate as the electrocatalytic route affects the performances of the degradation process in macro and microfluidic cells. Direct anodic oxidation (EO), electro-Fenton (EF), electro-generation of active chlorine (IOAC) and coupled processes were investigated in macro and microfluidic reactors in order to select more effective conditions for the treatment of such compound. The effect of numerous operative parameters (such as nature of the electrode materials, coupling of processes, flow rate, current density and inter-electrode distance) on the performances of the process was studied in detail. It was found that the catalytic route affects strongly the performances of the process in terms of removal of color, abatement of AO7 and COD and nature of by-products. Furthermore, different operative conditions were required to optimize the various electrocatalytic routes. The utilization of micro devices allowed to work without the addition of a supporting electrolyte and improved the performances of EO and EF that are kinetically controlled by mass transfer processes. On the other hand, the performances of IOAC did not depend on the adopted reactor.