Electrochemical oxidation of the Sunset Yellow in acidic medium using boron-doped diamond anode (BDD)

Sunset Yellow dye is widely studied due its various applications and is generally known for its great potential toxic mainly when used over concentration limits determined by legislation1. Studies reports several systems for the SY removal using oxidation electrochemical. In this case, BDD stands out as alternative for the complete oxidation of this compound2. This work shown electrochemical degradation of SY dye using BDD in acidic medium (Na2SO4 0.5 mol L-1; pH 3.0). The electrochemical system was a single compartment cell composed by BDD as work electrode, reference electrode (Ag/AgCl) and Pt wire as counter-electrode. To study of SY oxidation was applied 20 mA of current and small aliquots were collected in specific times. To study of color removal was used a UV-Vis spectroscopy Varian Cary 50. In order to verify the morphology aspects of deposition boron film on substrate that composes the electrode, were analyzed by optical microscopy. To verify electrochemical stability of the BDD, were performed chronoamperometry measurements before and after anodic studies. It was noted that the electrode remains stable and there was not changes toward to the low overpotential and high current density i.e., which shows that this anode is promising for SY oxidation. The color removal was 98% at 90 min. of electrolysis. The process kinetic was pseudo-first order, reaching apparent constant (kapp) value of ~ 1.0x10-2 min-1. The results will optimize and discussed in terms of electrochemical/chemical mechanism.