Inhibition of carbon steel corrosion by 11-aminoundecanoic acid

  • Saad Ghareba Department of Chemical and Petroleum Engineering, Al-Mergib University, Alkhums
  • Simon Kwan Department of Chemical Engineering, McGill University, Montreal, Quebec
  • Sasha Omanovic Department of Chemical Engineering, McGill University, Montreal, Quebec
Keywords: Corrosion inhibition, Self-assembled monolayers, Adsorption, Acidic medium

Abstract

The current study reports results on the investigation of the possibility of using 11-aminoundecanoic acid (AA) as an inhibitor of general corrosion of carbon steel (CS) in HCl under a range of experimental conditions: inhibitor concentration, exposure time, electrolyte temperature and pH and CS surface roughness. It was found that AA acts as a mixed-type inhibitor, yielding maximum inhibition efficiency of 97 %. The adsorption of AA onto the CS surface was described by the Langmuir adsorption isotherm. The corresponding apparent Gibbs free energy of AA adsorption on CS at 295 K was calculated to be −30.2 kJ mol–1. The adsorption process was found to be driven by a positive change in entropy of the system. PM-IRRAS measurements revealed that the adsorbed AA layer is amorphous, which can be attributed to the repulsion between the neighboring positively charged amine groups and a high heterogeneity of the CS surface. It was also found that the AA provides very good corrosion protection of CS of various surface roughness, and over a prolonged time.

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Published
26-09-2015
Section
Electrochemical Engineering