The Synergistic Inhibition Effect between Imidazoline and 2-Mercaptoethanol on Carbon Steel Corrosion in CO2-saturated 3.5% NaCl solution

Abstract

The synergistic effect of oleic-based imidazoline (OIM) and mercaptoethanol (ME) on the corrosion of carbon steel in produced water of petroleum exploitation was investigated using weight-loss, electrochemical measurements and X-ray photoelectron spectroscopy (XPS). Results showed that OIM-ME mixtures greatly reduced the corrosion rate of carbon steel, and raised the inhibition efficiency up to 89.6%, compared with individual OIM (73.1%) or ME (56.3%). The OIM-ME mixture is a mixed-type corrosion inhibitor, and the optimal molar ratio is 1:3. Based on EIS spectra and XPS surface analysis, a bilayer adsorption model was proposed to illustrate the synergistic inhibition mechanism.