Kopsia terengganensis ` alkaloids as potential green inhibitors for mild steel corrosion in CO 2-saturated 3.5% NaCl medium

• Main Authors: Hanafi, Wan Nur Huda Wan, Hamidon, Tuan Sherwyn, Hussin, M. Hazwan, Awang, Khalijah, Litaudon, Marc, Raja, Pandian Bothi, Azmi, Mohamad Nurul
• Format: Article
• Published: Elsevier 2024
• Subjects: QD Chemistry; TP Chemical technology
• Online Access: http://eprints.um.edu.my/45111/; https://doi.org/10.1016/j.geoen.2024.212992
• Institution: Universiti Malaya

The corrosion inhibition potential of alkaloids from Kopsia terengganensis bark extract (KTBE) in mitigating the mild steel corrosion in a CO 2 -saturated 3.5% NaCl medium was evaluated. Standard corrosion evaluation methods, including weight loss test, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PD) were employed, which revealing a concentration -dependent enhancement in KTBE ` s inhibition efficiency. At 500 ppm, the corrosion inhibition efficiency recorded the highest value of 90.63% based on the weight loss study and 87.38% based on electrochemical analysis. Tafel slopes in PD studies affirmed that KTBE functioned as an anodic -type inhibitor. The adsorption of the inhibitor is in accordance with the Langmuir adsorption isotherm with an adsorption free energy ( Delta G degrees ads ) of -26.47 kJ/mol, suggesting the binding of KTBE molecules by means of physisorption. Surface analysis conducted through scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared spectroscopy (FTIR) confirmed the formation of a protective inhibitive layer on the surface of mild steel. The proposed corrosion inhibition mechanism involves electrostatic interactions between KTBE molecules and the mild steel surface. This comprehensive investigation underscores KTBE ` s potential as an effective corrosion inhibitor in corrosive environments.