Corrosion inhibition and adsorption behaviour of an amido-imidazoline derivative on API 5L X52 steel in CO2-saturated solution and synergistic effect of iodide ions

Corrosion inhibition of an amido-imidazoline derivative on API 5L X52 steel in CO2 saturated 3 wt% NaCl solution was investigated. The effect of iodide ion additives was also studied by using electrochemical techniques. The results showed that amido-imidazoline derivative inhibited corrosion of steel and the extent of its inhibition was concentration dependent. Potentiodynamic polarization investigations revealed that amido-imidazoline acted as a mixed inhibitor showing anodic and cathodic behaviour. Furthermore, the inhibition efficiency of amido-imidazoline was enhanced by addition of iodide ions due to synergistic effect. It was also found that amido-imidazoline adsorbed chemically on the steel surface and followed the Langmuir adsorption isotherm.

► The CO2 corrosion inhibition of steel was studied by using imidazoline derivative.
► The inhibition efficiency of amido-imidazoline was enhanced by addition of I− ions.
► Amido-imidazoline acted as a mixed inhibitor showing anodic and cathodic behaviour.
► The adsorption of inhibitor on the steel surface followed the Langmuir isotherm.
► The studied inhibitor was chemically adsorbed on the surface of steel.