Experimental and Quantum Studies of Dysphania ambrosioïdes(L.) as Ecological Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Environment

The aim of the present study is the valorization of the plant Dysphania ambrosioides(L.) in the inhibition of corrosion. Analysis of the extract by gas chromatography revealed the dominance of ascaridole epoxide (16.53%), thymol (13.25%), and n-hexadecanoic acid (9.62%). In this research, the effect of the extract on corrosion inhibition of mild steel in 1.0 M HCl solution was analyzed using weight loss measurements, potentiodynamic, polarization (PP) and electrochemical impedance spectroscopy (EIS). From the generated results, the optimum value (E%) of Dysphania ambrosioidesleaf extract was recorded at 94%, 95%, and 93% at a concentration of 1.0 g/L according to weight loss methods, PP and EIS, respectively. Polarization curves indicated that the extract acted as a mixed-type inhibitor. Adsorption on the mild steel surface obeyed the Langmuir isotherm. The activation energy values ΔGads0(− 24.89 kJ.mol−1) confirmed a physical process of adsorption of this inhibitor. The study of adsorption kinetics showed a maximum inhibitory efficiency of 91.9% after 1 hour of immersion time. Scanning electron microscopy revealed the formation of a protective layer on the surface of the steel emerging in the inhibitor unlike that emerging in 1.0 M HCl which is heavily corroded. The structural and electronic properties of the main components of this extract were calculated using density functional theory (DFT) at B3LYP/6-31G (d, p), the results confirmed the high reactivity of the molecules of thymol and ascaridole epoxide to adsorb on the steel surface.