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

• Published in: Environmental technology Vol. 41; no. 11; pp. 1434 - 1445
• Main Authors: Diouf, Ibrahima, Dia, Oumar, Diedhiou, Moussa Bagha, Drogui, Patrick, Toure, Alpha Ousmane, Lo, Sidy Mambaye, Rumeau, Michel, Mar/Diop, Codou Gueye
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 11-05-2020; Taylor & Francis Ltd
• Subjects: Batteries; Cathodes; crystal violet; electro-Fenton; electro-reduction of O; Electrochemical cells; Electrochemistry; Electrode materials; Electrodes; Electrolysis; Exhausted batteries; Ferrous ions; Graphite; Hydrogen Peroxide; Injection; Iron; Oxidation-Reduction; Oxygen; Process parameters; Purification; Silver chloride; Water Pollutants, Chemical; electro-reduction of O2; Exhausted batteries; electro-Fenton; crystal violet; hydrogen peroxide
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2018.1537309

In this work, the study of hydrogen peroxide (H
2
O
2
) 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 O
2
to H
2
O
2
, while the second one corresponds to the reduction of H
2
O
2
to H
2
O. The cathodic potentials for electro-generation of H
2
O
2
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 H
2
O
2
formation. The effect of several operating parameters on H
2
O
2
production, such as the nature and concentration of the electrolyte, the pH, the presence of ferrous ions and O
2
injection were studied using Gr-Bat and VC electrodes, respectively. For both electrodes, the acidic medium was more favorable for H
2
O
2
electro-generation. The oxygen injection in solution promoted an increase of H
2
O
2
concentration, but its effect was more pronounced in the case of VC electrode. Application for crystal violet degradation by electro-Fenton revealed that Gr-Bat had the best purification performance. A removal rate of 73.18% was obtained with Gr-Bat electrode against 62.27% with VC electrode for an electrolysis time of 120 min. This study has demonstrated the possibility of recycling Gr-Bat by using them as cathode materials in the electro-Fenton process.