Novel Schiff base amino acid as corrosion inhibitors for carbon steel in CO2-saturated 3.5% NaCl solution: experimental and computational study

The corrosion inhibition and adsorption behavior of some novel Schiff bases based on amino acids on carbon steel in CO2-saturated 3.5% NaCl solution at 50 degrees C was investigated using gravimetric, potentiodynamic polarization, linear polarization resistance corrosion rate, and scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy analysis (EDAX) techniques. Results show that the inhibition efficiency increases when the inhibitor concentration increases. Potentiodynamic polarization curves reveal that the used Schiff bases are mixedtype inhibitors. Experimental data indicate that these Schiff base inhibitors adsorb at the carbon steel/solution interface according the Langmuir adsorption isotherm. SEM/EDAX was used to examine the surface morphology of carbon steel samples in the absence and presence of the inhibitors. Quantum chemical calculations were further applied to explain the experimental results.