Adsorption and Corrosion Inhibition of Atropa Belladonna Extract on Carbon Steel in 1 M HCl Solution

The inhibition effect of Atropa Belladonna extract (ABE) on the corrosion of carbon steel in 1 M HCl solution was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The adsorption process obeyed a Langmuir adsorption isotherm. ABE acts as a mixed-type but mainly anodic inhibitor in 1 M HCl. The calculated adsorption thermodynamic parameters indicated that the adsorption was a spontaneous, exothermic process accompanied by an increase in entropy. The maximum inhibition approached 96.6% in the presence of 500 ppm ABE using Tafel polarization technique. Quantum chemical parameters were also calculated, which provided reasonable theoretical explanation for the adsorption and inhibition behavior of ABE on C-steel. ABE constituents have been simulated as adsorbate on Fe (1 1 0) substrate and the adsorption energy have been identified on iron surface. The results obtained from different electrochemical techniques and theoretical calculations were in good agreement.