Corrosion Behaviour of Mild Steel in the Presence of Ceiba pentandra Extract in Acidic Solution: Adsorption and Mechanism

Christogonus O. Akalezi^1,2*, Nwanneamaka R. Oze¹, Patience Usman¹, Emeka E. Oguzie^{1, 2}

¹Department of Chemistry, Federal University of Technology Owerri, PMB 1526 Owerri, Nigeria

²African Center of Excellence in Future Energies and Electrochemical Systems, Federal University of Technology Owerri, PMB 1526, Nigeria

Corresponding Author: [email protected]; Tel: +2348080587128

Recieved Date: 26 December 2021; Accepted Date: 20 April 2022; Published Date: 03 May

Citation: Akalezi CO, Oze NR, Usman P, Oguzie EE. Corrosion Behaviour of Mild Steel in the Presence of Ceiba pentandra  Extracts in Acidic Solution: Adsorption and Mechanism. Trop J Nat Prod Res. 2022; 6(4): 606-614 http://www.doi.org/10.26538/tjnpr/v6i4.23

Copyright:

© 2022 Akalezi et al. This is an open-access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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ABSTRACT

Despite the sustained interest in applying plant extracts as inhibitors of metal corrosion, deducing the detailed mechanisms of the inhibition process continues to pose some experimental challenges. To assign the inhibitive effect to the adsorption of any particular constituent is difficult due to the complex chemical compositions of the extracts. Ceiba Pentandra extract (CP) was evaluated as a green and renewable corrosion inhibitor for mild steel corrosion in a 1.0 mol/L HCl solution. The inhibition behavior was studied using weight loss, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) measurements. In this study, the plant material was separated into various fractions and named the acidic fraction (AF), the basic fraction (BF), the neutral fraction (NF), and the crude fraction (CF). The basic fraction (BF), which yielded over 90% inhibition efficiency at the 500 mg/L dosage level, is considered the most promising fraction. PDP results suggest the BF was more a cathodic inhibitor while the rest were mixed-type inhibitors. Adsorption of the plant material on the mild steel surface obeyed the Langmuir adsorption isotherm.  The basic fraction was further analyzed using Gas chromatography-mass spectrometry (GC-MS). The GC-MS result shows that CP extract possesses polar functional groups such as hydroxyl, carbonyl, and hetero-aromatic rings. The inhibition mechanism is closely related to these polar groups.