Eco-friendly green inhibitor for corrosion protection of API 5L X60 carbon steel in sulfuric acid solution

Background: Corrosion is a widespread issue affecting metals and alloys across various industries. The use of corrosion inhibitors remains one of the most effective protection methods. Due to growing environmental and health concerns, the focus has shifted toward eco-friendly alternatives.Olibanum has emerged as a promising green corrosion inhibitor with potential applications in industrial environments. Methods: Temperature effect, Inhibition efficiency, corrosion behaviour and corrosion mechanism of the inhibitors on carbon steel are evaluated using gravimetry and electrochemical techniques (potentiodynamic polarization curves (PDP), electrochemical impedance spectroscopy (EIS), and open circuit potential). Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) examined the surface morphology. Furthermore, Infrared Spectroscopy (IR) is employed to characterize the inhibitor. Significant findings: The results show that this natural substance is a mixed-type inhibitor with anodic behavior dominating, with a maximum efficiency of 85% obtained at a concentration of 4 g/L. The inhibition efficiency of Olibanum increased with inhibitor concentration and temperature. The dynamic behavior of Olibanum shows that its adsorption isotherm on steel follows the Temkin type with both physicochemical adsorption processes. The low Ea, moderate Delta Hact, and Delta S act values provide that the adsorption appears to be predominantly physical, but there may also be some chemical adsorption. SEM micrographs confirm the presence of a protective layer on the steel surface.