Electro-generation of hydrogen peroxide using a graphite cathode from exhausted batteries: study of influential parameters on electro-Fenton process

ABSTRACTIn this work, the study of hydrogen peroxide (H2O2) electro-generation using graphite from exhausted batteries (Gr-Bat) was conducted. Linear sweep voltammetry and electrolysis experiments were carried out in a single compartment electrochemical cell. Study of the possibility to use this electrode revealed that it presents, as vitreous carbon (VC) electrode, a reduction of oxygen with two successive waves (bi-electronic reduction). The first wave corresponds to the reduction of O2 to H2O2, while the second one corresponds to the reduction of H2O2 to H2O. The cathodic potentials for electro-generation of H2O2 appeared at −600 and –700 mV vs. Ag/AgCl for Gr-Bat and VC electrodes, respectively. Subsequently, electrolysis experiments were conducted by imposing the potentials required for H2O2 formation. The effect of several operating parameters on H2O2 production, such as the nature and concentration of the electrolyte, the pH, the presence of ferrous ions and O2 injection were studied using Gr-Bat a...