A miniaturized injection-moulded flow-cell with integrated conducting polymer electrodes for on-line electrochemical degradation of azo dye solutions

Abstract

This study investigates the effectiveness of a novel micro electrochemical flow-cell containing carbon fiber electrodes for the degradation of Azo dye solutions. The flow-cell was fabricated by an injection moulding technique, integrating three electrodes system design using an overmoulding procedure. All electrodes were fabricated from carbon fiber polymer, however, the reference electrode was then coated with Ag/AgCl paste. The effect of the process variables such as flow-rate, NaCl concentration, applied bias current, and solution pH on the degradation process were comprehensively studied. At optimum conditions, complete degradation of the dye was achieved on the bare carbon fiber electrode, without the need for surface modification, in 150min upon the application of 15mA bias current. The degradation process was suggested to follow the indirect oxidation mechanism where the presence of chlorine ions was very essential. Moreover, the micro-flow-cell had proven its stability over the entire operation time, which indicates its practicality for such on-line applications.