Corrosion inhibition potential of aqueous extract of Trifolium repens plant leaves on carbon steel in hydrochloric acid medium (TRPL)

Abstract This research explores the effectiveness of a liquid extract derived from the leaves of Trifolium repens as a corrosion inhibitor for carbon steel in a 1N hydrochloric acid environment. Corrosion poses significant challenges in industrial applications, and this study aims to provide an eco-friendly solution by leveraging plant extracts. The experiment demonstrated that the application of the Trifolium repens extract substantially reduced the weight loss of carbon steel, indicating its efficacy in mitigating corrosion. Inhibition efficiency was quantified through systematic weight loss measurements, revealing a clear inverse relationship between the concentration of the extract and the corrosion rate. As the concentration of the inhibitor increased, the rate of corrosion correspondingly decreased, underscoring the extract's potential for effective corrosion prevention. The mechanism of inhibition was further elucidated through electrochemical techniques. Potentiodynamic polarization (PDP) tests and alternating current impedance spectroscopy were employed to assess the electrochemical behaviour of carbon steel in the presence of the extract. These analyses confirmed the formation of a protective layer on the steel surface, which effectively blocks active corrosion sites, thereby enhancing the material's resistance to acidic attack. To gain deeper insights into the surface modifications caused by the inhibitor, the surface characteristics of the carbon steel samples were analysed using scanning electron microscopy (SEM). This technique allowed for the observation of differences in morphology between unprotected, corroded, and inhibited steel surfaces. Additionally, atomic force microscopy (AFM) was utilized to evaluate the roughness of the surface layer, providing quantitative data on the changes induced by the inhibition process. Overall, the findings indicate that the Trifolium repens extract not only acts as a potent corrosion inhibitor but also contributes to the formation of a protective barrier on carbon steel, thereby extending its lifespan in corrosive environments. This study highlights the potential for utilizing natural extracts as sustainable alternatives for corrosion prevention in industrial applications.