Computational and experimental studies on the corrosion inhibition performance of an aerial extract of Cnicus Benedictus weed on the acidic corrosion of mild steel

Abstract

The corrosion inhibition investigation of aerial extract of Cnicus Benedictus, a weed referring to the Asteraceae family has been evaluated on the mild steel corrosion in 0.5 M HCl with the employment of the weight-loss method, potentiodynamic polarization measurements (PDP) and electrochemical impedance spectroscopy (EIS) techniques. This investigation demonstrated Cnicus Benedictus extract (CBE) as a green and sustainable mild steel corrosion inhibitor in 0.5 M HCl media exhibiting an inhibition efficacy of 92.45% at 1000 ppm. With the increased concentration of CBE, the value of icorr and corrosion rate (CR) decreased significantly from 7.4114 to 0.97438, revealing the protective effect of CBE on mild steel. The deposition of a highly defensive coating on the mild steel surface was demonstrated by the contact angle measurements. Additionally, the increase in the Kads values indicated a stronger interaction between the inhibitor molecules and metal surface. Furthermore, density functional theory (DFT) and Monte Carlo simulations have been utilized to validate the significant inhibition characteristic attained by the experimental study and to suggest an adsorption mechanism.