Cerium(IV) oxide-modified graphite anode for superior performance towards electrochemical treatment of the simulated textile dyebath effluent

Electrochemical anodic oxidation is an efficient technique to degrade synthetic textile dyes, which are difficult to remove by conventional wastewater treatments . The anode material is a very important factor affecting the degradation process. In this work, the graphite anode was electrochemically modified by CeO 2 to obtain a novel, superior graphite-CeO 2 anode. It was characterized by the SEM/EDX, XRD , and BET and used for electrodegradation of Reactive Black 5 dye in water and synthetic dyebath effluent. Degradation products were revealed. The modification did not disrupt the graphite crystal structure but caused slight changes in its XRD pattern . CeO 2 was detected as a separate phase. The graphite-CeO 2 anode's surface morphology differed from the graphite's one. The constant decolorization rate and the corresponding energy consumption of graphite and graphite-CeO 2 anode were 0.0188 and 0.0675 min −1, respectively, and 3.02 and 0.92 kWh m −3 , respectively (at a current density of 60 mA cm −2 , 0.05 mol dm −3 Na 2 SO 4 , pH 5.5, and t = 25 °C). COD decreased by 62 % and 89 % after 180 min, and TOC decreased by 42 % and 73 % after 200 min of electrolysis for the graphite and the graphite-CeO 2 anode, respectively, consuming approximately the same energy of about 2.2 kWh m −3 (COD) and 3.5 kWh m −3 (TOC). The simulated textile effluent decolorization energy consumption was 2.01 kWh m −3 and 4.99 kWh m −3 for the 85 % COD and 69 % TOC removal. The dye degradation assumingly proceeded via anodically generated ·OH radicals, the involvement of the CeO 2 as an electrocatalyst , and direct oxidation. It followed the pseudo-first order kinetics . Its rate increased with increasing the current density, background electrolyte concentration, and temperature, and with decreasing pH. This simple, effective, and eco-friendly modification significantly improved the graphite anode's efficacy and reduced energy consumption. • Graphite anode was modified by CeO 2 to obtain a novel graphite-CeO 2 anode. • Graphite-CeO 2 anode was used for electrodegradation of RB 5 dye in the water medium. • Modification with CeO 2 improved dye degradation rate and reduced energy consumption. • CeO 2 acted as an electrocatalyst , contributing to a superior performance of the anode. • Graphite-CeO 2 anode was successfully applied in the synthetic dyebath effluent.