Eriobotrya japonica Lindl leaves extract application for effective corrosion mitigation of mild steel in HCl solution: Experimental and computational studies

The feasibility of using Eriobotrya japonica Lindl (EJL) extract as a green inhibitor towards mild steel corrosion retardation in 1 M HCl solution was evaluated through integrated experimental and computational perspective. By utilizing electrochemical and surface analyses benefits, including EIS, potentiodynamic polarization, SEM, AFM and contact angle test, the protection function of EJL extract was studied. In addition, the EJL extract itself was examined by means of FT-IR and UV-Vis analysis. EIS results revealed the increase in mild steel corrosion resistance in the presence of EJL extract by increasing the extract concentration. The highest resistance was achieved at 800 ppm concentration. A mixed type behavior of EJL extract with dominant anodic dissolution reduction was proved by DC polarization. The lowest current density was obtained at 800 ppm concentration. SEM and AFM images indicated the protective layer growth on steel surface having intact surface morphology and more homogeneity in the presence of inhibitor. Contact angle test results confirmed the steel surface wettability enhancement by addition of EJL extract. The presence of functional groups, which make the inhibitors molecule adsorption possible, was verified by FT-IR and UV-Vis tests results. Furthermore, the computational methods (i.e., quantum mechanics and molecular simulations) evidenced the binding of EJL extract compounds onto steel substrate, affirming the inhibition action of EJL extract. (C) 2019 Elsevier Ltd. All rights reserved.