Exploring the inhibition performance of tetrachloroferrate ionic liquid in acid environment using scanning electrochemical microscope and theoretical approaches

Abstract

The corrosion inhibition performance of carbon steel by Benzyltributylammonium tetrachloroferrate ([BTBA]+[FeCl4]−)was investigated in 1 N HCl solution and compared with theoretical results. The electrochemical impedance results showed that [BTBA]+[FeCl4]−ionic liquid act as an effective inhibitor for carbon steel corrosion in acidic medium and maximum inhibition efficiency was found to be 99.5% at 400 ppm. The SECM results also confirmed the adsorption of [BTBA]+[FeCl4]−on carbon steel and thereby forming a relatively insulated surface at the interface. The adsorption of ferrate ionic liquid on carbon steel was found to obey Langmuir adsorption isotherm. Ionic liquid effectively inhibits anodic and cathodic reaction site thereby showed its mixed type inhibition behaviour. In presence of the inhibitor higher resistance values were obtained for impedance and polarization studies. The presence of ionic liquid and its surface protection tendency at the metal/solution interface was confirmed by SEM surface studies. UV–Vis and ATR-FTIR characterization also contributed in corroborating the complex formation between Fe2+ and ionic liquid. Monte Carlo simulation and quantum chemical parameters substantiated the experimental findings and gave further insights about the inhibition mechanism.