Eco-friendly corrosion protection for carbon steel: A study on natural inhibitors in artificial seawater and acidic environments

Abstract

Background: Inexpensive and environmentally friendly alternatives are needed to replace traditional organic inhibitors, as they are high in cost and pose risks to both human health and the environment. This study evaluated the performance of Cynodon Radiatus (CR) extract and its isolated constituent for inhibiting corrosion under artificial seawater in carbon steel and evaluated the inhibitors in acid-cleaning solutions for desalination plants. Methods: The inhibitor-isolated constituents were analysed using FTIR spectroscopy. The electrochemical (polarisation, bode plot and impedance spectroscopy) and gravimetric methods were used to evaluate the corrosion inhibition performance and confirm the Langmuir adsorption isotherm. FESEM studies confirmed the development of protective layers under inhibiting conditions. Significant Findings: The results exposed that the CR plant essences performed as a mixed-type protector along with a high inhibition efficiency (IE) of 96.9 % in an acid-cleaning medium compared to artificial seawater (91.4 %). In addition, the isolated constituents displayed a high IE (97.2 %) compared with whole plant extract under an acid medium. The high IE was credited to the adsorbing of inhibitor molecules by the metal surface as defined in the surface coverage and absorption processes. The Langmuir profile was used to describe the appropriate mechanism for the adsorption process of extract. These results indicate that the extract functions as a powerful and cheapest anticorrosive agent. © 2025 Taiwan Institute of Chemical Engineers