Sustainable production of toluene derivatives using electrochemical cells equipped with gas diffusion cathodes assisted by an absorption column

• Grant number: 24/06300-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: February 21, 2025
• End date: February 20, 2026
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Marcos Roberto de Vasconcelos Lanza
• Grantee: Florymar Escalona Durán
• Supervisor: Manuel Andres Rodrigo Rodrigo
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Universidad de Castilla-La Mancha, Ciudad Real (UCLM), Spain
• Associated to the scholarship: 23/05895-8 - Development and application of gaseous diffusion electrodes modified with lanthanum and cerium in the electrochemical/like-fenton treatments of benzotriazole, BP.PD

Abstract

The development of more efficient processes for the treatment of waste gas fluxes is becoming a necessity for real applications worldwide. In this sense, this proposal aims at the application of gas diffusion electrodes (GDE) modified with La2O3 and CeO2 nanoparticles, coupling the electrochemical system to an absorption column, to obtain value-added compounds from the oxidation of toluene. The studies will be carried out in a single-compartment electrochemical flow cell equipped with an GDE as the cathode, and the supply of oxygen and/or nitrogen gas will be carried out through the external layer of the electrode. A dimensionally stable anode (DSA) electrode will be used as the anode, and when applicable, an Ag/AgCl (KCl 3M) electrode will be used as a reference. Under the best experimental conditions obtained, absorption-assisted electrochemical oxidation treatments will be carried out, dragging gas flows contaminated with toluene along with the supply of oxygen gas. The contaminant will be transferred to the liquid phase by bubbling directly into the solution through the outer layer of the electrode and passing through a packed absorption column. The main challenge of this project is to control the selectivity and yield of the value-added products obtained, avoiding the total mineralization of the contaminant. In this sense, the composition of the liquid phase will be carefully studied: specific proportions of methanol will be added to the absorbent/electrolyte (K2SO4 0.05 mol L-1) to contribute to the pre-concentration of toluene. The electrogenerated hydrogen peroxide (H2O2) will be quantified with UV-Vis spectrophotometry and the efficiency of GDE in toluene degradation and generation of by-products will be evaluated using ion chromatography (IC), UV/Vis, HPLC, COD and TOC.