Comparative study of GO and reduced GO coated graphite electrodes for decolorization of acidic and basic dyes from aqueous solutions through heterogeneous electro-Fenton process

Abstract

In the present study, decolorization of two different dyes was enhanced by a simple heterogeneous Electro-Fenton degradation. Electro-Fenton removal was carried out using modified graphite electrodes (GE). Graphene oxide (GO) and reduced graphene oxide (rGO) were successfully synthesized to deposite on the surface of GE. Fe3O4 nanoparticle was produced as catalyst to generate Fe+3 Fe2+ ions leading to produce high reactive agents, H2O2 and OH. Na2SO4 was used as electrolyte to enhance current value in the solution. Effect of the modified cathode (GO-GE and rGO-GE) and also operating factors such as magnetic loading, electric current, pH and dye concentration on dyes degradation were examined. In addition, cyclic voltammetry (CV) was used to characterize electrochemical properties of modified cathodes in degradation capacity of Methylene Blue (MB) and Acid Red 14 (AR14). The experimental result indicated that magnetic supported reaction is effective in removing dye molecules in both acidic and alkaline pH. In some cases it was shown that electric current and Fe3O4 concentrations have optimum value. CV diagrams confirmed the experimental results and better electrochemical properties of rGO-GE to degrade dyes. CV measurements were in accordance with experiments that MB are more recalcitrant to degrade rather than AR14.