Experimental Investigation of New Compound Adsorption on Carbon Steel in 1M HCl

The effect of new compounds named, 6,6'-(((2,2-dimethylpropane-1,3-diyl)bis(azanediyl))bis(methylene))bis(2-methoxyphenol) (RSH) on the corrosion inhibiting of ST-37 low carbon steel in 1.0 M HCl has been studied. The inhibitor effects on the corrosion behaviour of the samples have been determined at three different concentrations, 0.5, 1.0, 1.5 and 2.0 mg/L. Weight loss, polarization curves, AC impedance measurements and Atomic Force Microscopy (AFM) have been utilized to study the corrosion behaviour of carbon steel in corrosive environment in the presence and absence of new ligand. Results show that the inhibition occurs through adsorption of the inhibitors molecules on the metal surface. The inhibition efficiency was found to increase with increasing inhibitor’s concentration. Polarization data indicated that this compounds act as mixed-type inhibitors. The corrosion efficiency of RSH at an optimal concentration of 2 mg/L is 86. The adsorption of inhibitors follows the Langmuir isotherm. The values of free energy of adsorption in the presence of the corrosion inhibitor are around -32 KJmol^-1, which indicate chemiosorption of the molecules. Powerful Atomic Force microscopy is used for the surface morphology studies.