Insight into corrosion inhibition mechanism of carbon steel by an algal extract as an eco-friendly corrosion inhibitor in 0.5 M H2SO4: Experimental and molecular dynamics study

To explore the potential of new ecological corrosion inhibitors, we investigated the mechanism of corrosion inhibition in carbon steel using Halopitys incurvus, an algal extract available in both crude and chromatographic fractions, in a 0.5 M H2SO4 medium. Various methods were employed, including gravimetry, electrochemical impedance spectroscopy, polarization curves, scanning electron microscopy (SEM) techniques, and molecular dynamics. The crude extract exhibited a high corrosion-inhibiting potential, with a maximum inhibitory efficiency of 85.30% at 600 mg/L. The electrochemical results indicated mixed behavior of the crude extract. Furthermore, we found that the adsorption of the crude extract onto the metal surface followed the Langmuir isotherm pattern. The SEM study confirmed our proposition that extract molecules were adsorbed onto the carbon steel surface. Using the chromatographic fractionation protocol, we were able to distinguish four main fractions, and the most effective fractions reached an inhibitory efficiency value of 96.00% at 100 mg/L. The molecular dynamics simulation confirmed the experimental results.