Molecular-MD/atomic-DFT theoretical and experimental studies on the quince seed extract corrosion inhibition performance on the acidic-solution attack of mild-steel

Due to the more and more attention to environmental issues in recent years, the employment of eco-friendly corrosion inhibitors is the main topic of most studies. In this matter, the quince seed extract, which has been used for hundred years as traditional medicine was used as a new environmentally-friendly corrosion inhibitor of MS exposed to 1 M HCl solution. Characterization techniques (i.e., FT-IR and UV-Vis spectroscopies) demonstrated that there are several physical/chemical adsorption active sites in the extracted compounds. EIS results showed that after 24 h immersion of the electrode in the acid electrolyte containing 800 ppm extract, the R-p, and the C-dl increased about 95% and decreased about 87%, respectively. In addition, the PDP test results confirmed that the efficiency of the iron dissolution mitigation increased with the quince seed extract content increment and reached about 95% at 800 ppm. Furthermore, the R-p in the inhibitor-containing electrolyte (800 ppm) increased about 96% compared to the solution without the inhibitor. The electrochemical results proved the inhibitor action on both corrosion reactions (anodic (A)-cathodic (C)) control for MS in 1 M HCl and obeyed a Langmuir adsorption isotherm. In addition, the obtained adsorption free energy (Delta G) of -32.48 kJ/mol indicates that the GOI interaction with the MS surface was a mix of physical and chemical adsorptions. Also, the theoretical results obtained from molecular simulations (Monte Carlo, MC and Molecular Dynamics, MD) approved the adsorption of the green ingredients on the steel. The DFT calculations supported the interfacial interactions of the inhibitors through their reactive sites. (C) 2021 Elsevier B.V. All rights reserved.