Electrochemical investigation of different electrodes toward the removal of non-basic nitrogen compound from model diesel fuel

Abstract

• Electrochemical denitrification of non-basic nitrogen compound in model diesel fuel. • Electrooxidative investigation of pyrrole in divided cell using several electrodes. • Electrooxidation and electropolymerization as two dominated proposed mechanism. • Carbon-based electrodes have better tendency towards oxidation than polymerization. • CP electrode could attain highest denitrification and current efficiency. In this study, the electrochemical removal of pyrrole as a non-basic nitrogen compound in diesel model fuel was investigated using platinum (Pt), graphite (Gr), carbon paper (CP), lead/lead dioxide (Pb/PbO 2 ), and tin/tin dioxide (Sn/SnO 2 ) working electrodes in a divided cell. Electrochemical analysis such as cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectrometry, and Tafel test was utilized to determine different behavior of electrodes. According to gas chromatography results, pyrrole removal efficiency at a constant current density of 17 mA cm −2 during 6 h was in the range of 83%–100% for Sn/SnO 2 and CP electrodes, respectively. The denitrification reaction using CP, Gr, and Sn/SnO2 electrodes was diffusion-controlled regarding data extracted from cyclic voltammetry at various scan rates. However, the adsorption mechanism was dominated by Pt and Pb/PbO 2 electrodes. Tafel analysis demonstrated that the electrocatalytic activity of electrodes is as follows: Pt > CP > Gr > Pb/PbO 2 > Sn/SnO 2 . Besides, the formation of polypyrrole and low oxygen evolution potential diminished Pt pyrrole removal efficiency. Carbon-based electrodes with pyrrole oxidation potential near Pt electrode and higher oxygen evolution potential can be utilized as efficient and cost-effective electrodes in the denitrification process.