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.

The corrosion of metals in acidic environments remains a significant challenge, driving the search for sustainable and eco‐friendly inhibitors derived from natural sources. This study evaluates the corrosion inhibition potential of three extracts from Cannabis sativa L., namely ethanol extract (EET), hexane extract (EHX), and dichloromethane extract (EDM), for mild steel in a 1 M HCl acidic medium. The investigation employed weight loss (WL) measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques. To understand their inhibitive performance, density functional theory (DFT) was used. For a more comprehensive theoretical analysis, Monte Carlo (MC) and molecular dynamics (MD) simulations were used. The corrosion inhibition efficiency increased with the increase of EET, EHX, and EDM concentrations up to 91 %, 89 %, and 83 %, respectively, obtained at 308 K for a 0.8 g/L concentration. Polarization studies classify EET, EHX, and EDM as mixed‐type inhibitors with a predominantly anodic effect, functioning through adsorption on the metal surface. The adsorption of these extracts on mild steel conforms to the Langmuir isotherm model, with adsorption equilibrium constants (K _ads ) of 3.0143 M, 5.1245 M, and 2.2009 M for EET, EHX, and EDM, respectively, highlighting their potential as effective corrosion inhibitors. The EET extract exhibits a high activation energy (E _a ) of 101.70 kJ/mol, while the EHX and EDM extracts show E _a values of 79.05 kJ/mol and 82.93 kJ/mol, respectively, all significantly higher than the E _a of blank, which is 30.23 kJ/mol, indicating that the extracts effectively inhibit corrosion by increasing the activation energy, with EET being the most potent inhibitor. Theoretical approaches based on DFT, MC, and MD simulations clearly explain the mode of adsorption of the majority of molecules on the metal surface. The inhibition process may result from a synergistic intermolecular effect of the major compounds in the extract, which interact at various active adsorption sites on the metal surface. Simulations indicate that catechin dihydrate in EET (52.42 %), linoleic acid in EHX (42.92 %), and naringenin in EDM (41.92 %) are close to the metal surface, suggesting strong interactions with the material. The results obtained from experimental measurements and theoretical calculations agree, highlighting the potential for developing more sustainable corrosion inhibitors based on plant‐derived compounds.