Synthesis and study of corrosion behavior of terephthalaldehyde-derived schiff base for low-carbon steel in HCl: experimental, morphological and theoretical investigation

In the present investigation, corrosion inhibition assays of the terephthalaldehyde-derived Schiff base of low-carbon steel have been performed in a 1.0 mol L⁻¹ hydrochloric acid solution. Weight loss measurements were applied to investigate the corrosion inhibition efficacy of Schiff base as an inhibitor. The highest inhibitive efficacy was achieved at a select concentration of 500.0 ppm for the tested inhibitor. The Langmuir adsorption isotherm model was applied to portray the adsorption inhibition mechanism. The variation in the activation energy value in the presence of synthesized inhibitor indicates the types of interactions between the inhibitor molecules and low-carbon steel surface. Scanning electron microscopy analyses proved the adsorption of inhibitor molecules on the low-carbon steel surface and through form a film that protects the metallic surface from corrosion. Furthermore, the relationship between inhibitive efficacy and the inhibitor molecule structure was studied theoretically through density functional theory (DFT). The experimental and theoretical findings reveal compatible harmony between them.