Boron-doped diamond electrodes for carbofuran electrochemical degradation

Resumo

Boron-doped diamond electrodes were produced on titanium substrate by Hot Filament Chemical Vapor Deposition reactor for electrochemical degradation of carbofuran pesticide. The morphological and structural characterizations of the electrodes were evaluated by Scanning Electron Microscopy and by Raman scattering Spectroscopy techniques. The apparent space charge density (NA) value was determined by Mott-Schottky Plot, which is approximately 1019 cm-3. The electrochemical characterization of electrodes was performed by Cyclic Voltammetry, and it was observed large potential windows. The electrochemical oxidation of the carbofuran were performed at different current densities, flow rates of 50 and 300 Lh-1 for a total of 2 hours with an electrolyte aqueous solutions K2SO4 0.1M and carbofuran concentration of 1,8 x 10-3 M in a flow reactor with recirculation. The efficiency of the pesticide degradation process was monitored by UV–Vis Spectrophotometry, Total Organic Carbon (TOC) and High Performance Liquid Chromatography (HPLC) techniques. The obtained results show that Ti/BDD anodes are promising for electrochemical treatment in the wastewater. The reducing the TOC concentration promoted a breakdown of the carbofuran molecule rather than the mineralization of organic matter. This fact may have contributed to the formation of carbofuran intermediates resulting from the reaction of degradation of the pesticide.