In this modest work, a local biopolymer (CHA), biodegradable, non-toxic, and soluble in acidic media, was extracted from the plant Artemisia herba-alba located in the eastern region of Morocco, and characterized by FT-IR, in order to valorize it as a corrosion inhibitor of mild steel in 1 M HCl medium. The electrochemical tests show that the extract is an excellent corrosion protective agent, reaching a maximum value of 96.17% at the concentration of 800 mg/L in the inhibitor. The potentiodynamic polarization (PDP) curves indicate the mixed behavior of the extract, to reduce the current density from 3.445 mA/cm² to 0.104 mA/cm² in the presence of 800 mg/L in the inhibitor. The biopolymer CHA of the extract of Artemisia herba-alba undergoes the Langmuir adsorption isotherm, whose adsorption energy is −20.75 kJ/mol, which is attributed to the presence of electrostatic and covalent bonds. In addition, the visualization of the metal surface by a scanning electron microscope (SEM) indicates the formation of a protective layer formed by the extracts of Artemisia herba-alba, which confirms the protective characteristic of the extract used. Theoretical investigations by DFT, MD, and MC confirm previous experimental results.

In the present work, essential oil of Calamintha (EOC) was extracted from Calamintha plant and characterized by gas chromatography-mass spectrometry (GC-MS) and FTIR technique. In addition, EOC was evaluated as an ecological corrosion inhibitor of mild steel in 1 M HCl medium by various electrochemical techniques. Satisfactory consistency was obtained between the gravimetric method, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The maximum efficiency was recorded for the concentration of 1.5 g/L EOC which reached 87.57%. However, the morphology of the metal surface analyzed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed the appearance of a protective barrier on the steel surface. Finally, a theoretical study was carried out on the basis of the density functional theory (DFT) and molecular dynamics (MD) simulation technique.