Original scientific paper
https://doi.org/10.5599/jese.353
Inhibitory action of Vernonia amygdalina extract (VAE) on the corrosion of carbon steel in acidic medium
Olamide Olawale
; Department of Chemical Engineering, College of Science and Engineering, Landmark University, Omu-Aran, Kwara State, Nigeria
Adeolu Adesoji Adediran
; Department of Mechanical Engineering, College of Science and Engineering, Landmark University, Omu-Aran, Kwara State, Nigeria
Segun Isaac Talabi
; Department of Materials and Metallurgical Engineering, University of Ilorin, Ilorin, Nigeria
Geraldine Chika Nwokocha
; Department of Chemical Engineering, College of Science and Engineering, Landmark University, Omu-Aran, Kwara State, Nigeria
Alewo Opuada Ameh
; Chemical Engineering Department, Ahmadu Bello University, Zaria, Nigeria
Abstract
This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the corrosion of mild carbon steel immersed in 1 M HCl solution containing various concentrations of the inhibitor. The corrosion rate and inhibition efficiency were evaluated using mass loss and adsorption techniques. The results revealed that VAE efficiently inhibits the corrosion rate of mild carbon steel immersed in the acidic medium. The concentration of 0.6 g/L provides the highest inhibition efficiency of 78.1 %. The adsorption process was consistent with the physisorption mechanism and obeyed the Langmuir isotherm. The functional groups responsible for inhibition were identified using Fourier-transformed infrared (FTIR) spectra. The surface morphology of the corroded samples examined with scanning electron microscopy (SEM) revealed the presence of protective oxide layer. Inhibition efficiency was found dependet on the presence of oxalate, phytate, tannins, saponins and flavonoids in the VAE. It has been concluded that VAE is safe, cheap and efficient corrosion inhibitor for mild carbon steel.
Keywords
Phytochemical; Vernonia amygdalina stem extract; Mild steel degradation; Inhibition efficiency; hydrochloric acid
Hrčak ID:
185734
URI
Publication date:
15.8.2017.
Visits: 1.583 *