Removal of Methylene Blue by Direct Electrochemical Oxidation Method Using a Graphite Anode

The present work is to degrade methylene blue dye from aqueous solution by direct electrochemical oxidation technique. For this purpose an electrochemical cell was used comprising of two electrodes made from graphite as anode and stainless steel 316 grade as cathode. Different operating parameters that affected the treatment process such as current density, electrolyte temperature and initial dye concentration had also been studied. The reaction mechanism of direct anodic oxidation of M.B. is undertaken and the kinetic follows a pseudo first order reaction. Results revealed that at 20ºC electrolyte temperature, 10 mA/cm² current density, 0.5 g/l Na₂SO₄ as supporting electrolyte and 60 min electrolysis time, the decolorization percents for initial concentrations of M.B. 50 and 400 mg/L were 72.51% and 77.94% respectively while at 60ºC the decolorization percent 99.75% and 99.60% respectively for the same others operating conditions. The power consumption increased from 2.055 to 11.714 Kw.h/m³ at applied voltage 14.6 V and 28.5 V respectively. (paper)