Study of agrochemical degradation paraquat, sodium-metham and carbaryl by Electrochemical Advanced Oxidation Process (EAOP) using gas diffusion electrode modified with bimetallic oxides

Abstract

The major environmental problem in many countries of the world, including Brazil, is the pollution of surface water and the discharge of agricultural wastewater contaminated by recalcitrant organic compounds. According to this situation, it is necessary to develop new technologies for the treatment of contaminated effluents, as in the case of Advanced Oxidation Processes (AOP). Some of the AOPs use hydrogen peroxide (H2O2) as a precursor of the hydroxyl radical (*OH), which can be electrogenerated in situ by means of the O2 Reduction Reaction (ORR) using Gas Diffusion Electrodes (GDE). In this research project will be synthesized and characterized bimetallic oxides (La, Nb, Hf and Zr) incorporated to a Printex L6 carbon matrix to act as catalysts to generation of H2O2. Studies using mentioned metals oxides resulted in both the increase of H2O2 generation and decrease of oxygen reaction reduction potential, that is promising to the studies of them synergism as electro-catalystic for ORR. The most promising materials will be used as a modifier in the GDE electrodes preparation, which will be applied later in the pesticides degradation (paraquat, sodium-metham and carbaryl) using a bench cell and an electrochemical flow reactor. The AOPs used as degradation method will be electro-Fenton, photoelectro-Fenton and H2O2/UV. The degradation monitoring will be evaluated using High Performance Liquid Chromatography (HPLC), Liquid Chromatography coupled with Mass Spectrometry (LC-MS), Total Organic Carbon (TOC), Íon Chromatography (IC) and ecotoxicity essays. (AU)