Investigation of the inhibitive effect of quaternary ammonium surfactant mixture synthesized from Kerosene petroleum fraction on corrosion of carbon steel pipelines in HCl 1M

Quaternary ammonium cationic surfactant was synthesized from Kerosene, via chloromethylation/quaternization sequences. The thus-obtained petroleum surfactant was evaluated as corrosion inhibitor for carbon steel in 1 M HCl, by gravimetry, potentiodynamic polarization and electrochemical impedance spectroscopy. The corrosion inhibiting efficiency was assessed as functions of surfactant concentration. The results showed that the inhibiting efficiency increased with surfactant concentration; its optimal value of 79 % was for a surfactant concentration of 400 mg/L at 25 °C. Potentiodynamic polarization measurements showed that the mixture acts as mixed type inhibitor. The corrosion inhibiting mechanism is thought to proceed via an adsorption of the surfactant molecules on the steel surface, generating a film and hindering the active sites. Our experimental adsorption data were found to obey Langmuir adsorption isotherm. SEM images of the treated specimens, revealing the likely formation of a protective film, demonstrated the inhibiting capacity of the petroleum quaternary ammonium surfactant against the carbon steel corrosion.