Development and application of gaseous diffusion electrodes modified with lanthanum and cerium in the electrochemical/like-fenton treatments of benzotriazole

• Grant number: 23/05895-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: November 01, 2023
• Status: Discontinued
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Marcos Roberto de Vasconcelos Lanza
• Grantee: Florymar Escalona Durán
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination, AP.TEM
• Associated scholarship(s): 24/06300-0 - Sustainable production of toluene derivatives using electrochemical cells equipped with gas diffusion cathodes assisted by an absorption column, BE.EP.PD

Abstract

This project aims at the development, characterization and application of gas diffusion electrodes (GDE) modified with metals from the lanthanide group in the treatment of alkaline aqueous systems contaminated with benzotriazole. The system consists primarily of the production of hydrogen peroxide (via the oxygen reduction reaction through the two-electron process); and, then, the use of this as a precursor of hydroxyl radicals (—OH) that will act in the degradation of the contaminant. La2O3 and CeO2 nanoparticles will be synthesized following a precursor polymer method and characterized with TGA, DRX, SEM, MET, N2 physisorption (BET) and XPS. For the manufacture of cathodes, appropriate proportions of Printex 6L carbon and metallic catalysts will be deposited on carbon fabric and then a lamination and hot pressing process will be carried out. The electrochemical and morphological characterization of the electrodes will be carried out with studies of cyclic voltammetry and linear scanning voltammetry, XRD, TEM, SEM and XPS. Then, the voltammetric and chronopotentiometric studies were carried out in a one-compartment glass electrochemical cell, with oxygen gas supplied through the outer layer of the working electrode; therefore, under the best experimental conditions obtained, electrochemical/like-Fenton treatments will be carried out, assisted by cerium ions (an alternative catalyst that under alkaline conditions can generate the waxy form (Ce3+) that is easily oxidized by oxygen), with a view to seeking new alternatives for the degradation of organic compounds, avoiding the strict acidic conditions of the traditional Fenton process. The hydrogen peroxide concentration will be monitored with UV-vis spectrophotometry and the efficiency of gas diffusion cathodes in the degradation of benzotriazole will be evaluated using ion chromatography (IC), UV/Vis, HPLC, COD and TOC. Finally, the stability and lifetime of the cathode materials will be evaluated in order to propose the scale up of the electrochemical cell that will allow evaluating the profitability and efficiency of the proposed electrodes on a large scale. (AU)