Sponge-like europium oxide from hollow carbon sphere as a template for an anode material for Reactive Blue 52 electrochemical degradation

Abstract

The textile industry is one of the major pollutants of waterbodies with effluents high in biochemical and chemical oxygen demand values, high values of total dissolved solids, total suspended solids, and low dissolved oxygen values along with strong color. The existence of a successful method for its decontamination would be beneficial. In this work, we synthesized sponge-like europium oxide (Eu2O3) using a template-directed route from carbon hollow spheres, obtained from glucose as a carbon source. The material synthesis method was done in an aqueous environment, without using any organic solvents. Electrochemical properties of the synthesized material were investigated using cyclic voltammetry and electrical impedance spectroscopy, while morphological characterization was done using scanning electron microscopy and X-ray powder diffraction analysis. Eu2O3 were successfully immobilized at the surface of a screen-printed carbon electrode (Eu2O3/SPCE) using the drop-casting method. Finally, the prepared electrodes were tested toward the removal of Reactive Blue 52 (RB52) using electrochemical advanced oxidation processes (EAOPs). Important parameters, that is, the supporting electrolyte, its concentration, pH value, and the applied voltage, were optimized for RB52 degradation. The rate of removal was monitored spectrophotometrically and by high-performance liquid chromatography with a diode array detector (HPLC-DAD). It was found that the proposed approach reaches complete decolorization of the RB52 solution after a 60-min treatment, at pH 5.6 of KCl supporting electrolyte at a concentration of 0.05 M. Under optimal parameters, after 3 h of treatment, total organic carbon (TOC) was lowered by ~40%. The obtained results indicate that the proposed method may find potential application in EAOPs, considering electrode stability, durability, and efficiency and simplicity of the method.