Alkylimidazolium bromides as corrosion inhibitors for mild steel in acidic medium

Abstract

Inhibition of mild steel corrosion in 1 M HCl solution by 1-alkyl-3-methylimidazolium bromides was investigated using electrochemical and weight loss methods. The studied ionic liquids showed appreciable inhibition efficiencies. Polarization measurements proved that the studied compounds were mixed-type inhibitors with predominantly anodic inhibition. The inhibition efficiency increased with the ionic liquid concentration and with the length of the alkyl chain. The values obtained from the polarization curves and weight loss measurements were in good agreement. The highest inhibition efficiency reached for the 1-octyl-3-methylimidazolium bromide was 94%. The Gibbs energy of adsorption was calculated by means of the Langmuir and Flory-Huggins isotherm and El-Awady thermodynamic-kinetic model.