Performance of Acetone Extract of Anthocleista grandiflora as a Potential Bioinhibitor on Corrosion Behavior of Carbon Steel in Seawater Environment

In this study, we evaluated the potential of Anthocleista grandiflora leaf (AGL) plant extract as an environmentally friendly and cost-effective corrosion inhibitor for carbon steel in seawater. We employed various experimental methods, including gravimetric analysis, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Our findings indicate that increasing the concentrations of the AGL extract results in higher charge transfer resistance (Rct ) and reduced double-layer capacitance (Cdl ), suggesting the effective adsorption of AGL extract on the surface of carbon steel. The inhibition efficiencies were notably high, 98.7%, 92.40%, and 90.7% determined with gravimetric analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. Polarization analysis revealed that the AGL extract acted as a mixed-type inhibitor. Moreover, the results obtained from different techniques exhibited a consistent agreement. The SEM images revealed that the surface layer formed by the AGL extract on the mild steel surface further devoids the surface from pitting as the extract concentration increases. Comparative analysis with similar bio-based inhibitors suggested that the tested AGL extract holds a significant promise as a corrosion inhibitor for carbon steel in seawater. Therefore, our findings support the recommendation of utilizing this AGL extract as an effective anti-corrosion agent in marine industries, owing to its green, low-cost, and efficient characteristics.