Boron-doped diamond electrodes for carbofuran electrochemical degradation

Boron-doped diamond electrodes (BDD) were produced on titanium (Ti) substrate by Hot Filament Chemical Vapor Deposition (HFCVD) reactor for electrochemical degradation of carbofuran pesticide. The morphological and structural characterizations of the electrodes were evaluated by Scanning Electron Microscopy (SEM) and by Raman scattering Spectroscopy techniques. The apparent space charge density (N A ) value was determined by Mott-Schottky Plot, in which was approximately 10 19 cm -3 . The electrochemical characterization of electrodes was performed by Cyclic Voltammetry, and it was observed large potential windows. The electrochemical oxidation (EO) 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 0.1 M potassium sulfate (K 2 SO 4 ) aqueous solutions and 1,8 x 10 -3 M carbofuran in a flow reactor with recirculation. The efficiency of the pesticide degradation process was monitored by Ultraviolet-Visible Spetrophotometry (UV-Vis), Total Organic Carbon (TOC) and High Performance Liquid Chromatography (HPLC) techniques. The obtained results show that boron doped diamond on titanium substrate (Ti/BDD) anodes are promising for electrochemical treatment in the wastewater. The reducing the TOC concentration, promoted a breakdown of the carbofuran molecule, showing inorganic carbon (CO 2 , CO, H 3 CNH 2 ) formation, rather than the mineralization of organic compounds. This fact may have contributed to the intermediate products formation resulting from the reaction of degradation of the pesticide.