Nickel foam a suitable alternative to increase the generation of Fenton's reagents

• The applicability of nickel foam as cathode in electro-Fenton process was confirmed.
• Nickel foam increases the hydrogen peroxide generation in electro-Fenton process.
• High reusability as cathode by decolorization of Poly R-478 in successive batches.
• Nickel foam can be used in successive batches without operational problems.

One of the bottlenecks often faced in environmental processes is focused on the design of efficient technologies. Thus, the hunt of suitable alternatives is a must to be tackled in order to improve the conventional methods. In this study the applicability of nickel foam as cathode in electro-Fenton's treatment of Poly R-478, a recalcitrant dye, was demonstrated. Linear sweep voltammetry and initial studies show the ability of nickel foam to increase the H2O2 generation during the electro-Fenton treatment, enhancing the removal yields achieved in comparison with other carbonaceous materials. Furthermore, complete mineralization of the pollutant was reached when using Boron Doped Diamond (BDD) as anode. A heterogeneous electro-Fenton process using iron loaded polyacrylamide hydrogels enhance the efficiency of the process with respect to homogeneous electro-Fenton and anodic oxidation technologies. Furthermore, the evaluation of the generated hydroxyl radicals confirms the obtained results. Finally, the reusability of the designed process was evaluated by decolorization of Poly R-478 in successive batches. SEM study of the nickel foam along the successive experiments confirms that no structure changes were detected.Summing up, nickel foam seems to be a suitable cathode material for the electro-Fenton treatment of recalcitrant compounds in continuous mode.