STUDY ON SOME PARAMETERS AFFECTING DEGRADATION OF METHYLENE BLUE IN WATER BY ELECTRO-FENTON USING Ti/PbO2 ANODE

Abstract

In this work, a system combining two advanced oxidation processes, namely electro-Fenton (EF) in which the hydroxyl radical *OH is generated by reactions on the cathode and anodic oxidation (AO) in which *OH is produced directly on the anode, was studied to evaluate the treatment of methylene blue (MB) dye in aqueous solution. This electrochemical system was equipped with a commercial carbon felt cathode and lead dioxide-coated titanium (Ti/PbO2) anode. The effects of operating parameters such as pH, applied current (I), electrolysis time (t), catalyst concentration ([Fe2+]) and initial MB concentration (C0) on MB removal efficiency were investigated through monitoring MB concentration. The optimal process was achieved at the condition of [Fe2+] = 0.1 mM; pH 3.0; [Na2SO4] = 0.05 M; i = 2.5 mA.cm-2 and after 60 min of electrolysis, where 92.19 % of MB was removed. This performance was much higher than that of single EF system using carbon felt cathode and Pt anode (73.77 %) or single AO system using Ti cathode and Ti/PbO2 anode (58.04 %), which were also tested under optimal conditions. These experimental results have demonstrated that the combination of EF and AO is a prospective method for the destruction of persistent dyes.