Theoretical design coupled with experimental study of the effectiveness of the inhibitive molecules based on Cynara scolymus L extract toward chloride-induced corrosion of steel

Abstract

The application of corrosion inhibitors on metallic surfaces is sorely vital for increased longevity with lessened maintenance costs. In this paper, Cynara scolymus L extract was tested as a green/bio-degradable corrosion inhibitor for mild steel in sodium chloride solution by using electrochemical techniques. Hence, the ultraviolet-visible spectrophotometry (UV–Vis) and Fourier transform infrared (FT-IR) spectroscopy were conducted for Cynara scolymus L extract characterization. The electrochemical results indicated that the values of corrosion current density and double-layer capacitance decreased as time increased. The polarization results revealed that the nature of Cynara scolymus L adsorption is mixed with dominantly anodic. The results also suggest that the inhibition power is 96.1% at 1000 ppm in the sodium chloride solution. The corrosion inhibiting action of the Cynara scolymus L is ascribed to the process prohibition due to the surface film formation over the mild steel surface. The computer modeling (including molecular dynamics (MD), density functional theory including dispersion corrections (DFT-D), and Monte Carlo (MC)) achievements further supported the adsorption of Cynara scolymus L molecules on the mild steel surface. Furthermore, the DFT-D calculations suggested the adsorption of the inhibitor via electronic donor-acceptor interactions. As a result, the Cynara scolymus L is a practical green/bio-degradable inhibitor that helps to tailor the corrosion obstacles of mild steel for injection water and cooling systems.