Natural Products for Materials Protection: Mechanism of Corrosion Inhibition of Mild Steel by Acid Extracts of Piper guineense

Abstract

The adsorption and corrosion inhibiting effect of acid extracts of Piper guineense (PG) leaves on mild steel corrosion in 1 M HCl and 0.5 M H2SO4 was investigated using gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopy techniques as well as scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The polarization and impedance results revealed that PG inhibited the cathodic and anodic partial reactions of the corrosion process via adsorption of the extract organic matter on the metal/solution interface. The mechanism of adsorption deduced from the variation of inhibition efficiency with temperature as well as kinetic and activation parameters suggest significant chemisorption of the extract constituents on the metal surface. Density functional theory calculations were performed to model the electronic structures of some extract constituents, including chemisorptive interactions with the Fe surface.

Exploiting the Anticorrosion Effects of Vernonia Amygdalina Extract for Protection of Mild Steel in Acidic Environments

“…The results are in good agreement with that reported by [38]. The maximum values of the inhibition efficiency in both acid solutions were comparable; 94.5% (in 1 M HCl) and 96.6% (in 0.5 M H 2 SO 4 ).…”

Potential of Azadirachta indica as a green corrosion inhibitor against mild steel, aluminum, and tin: a review

“…The use of quantum chemical methods in corrosion inhibitor studies of large number of small organic compounds has been highlighted by Gece (2008) and Obot (2014) in their detailed review. Attempt has also been made recently to extend the application of DFT-based quantum chemical and molecular dynamic simulations methods in order to understand the mechanism of adsorption of plant extract components on metal and alloys surfaces (Oguzie et al 2013;Oguzie et al 2010;Oguzie et al 2012a;Umoren et al 2014;Oguzie et al 2012b;Obi-Egbedi et al 2012). This is because the major criticism of the use of plant extract as corrosion inhibitor is often the inability to pinpoint which of the component(s) is/are actually responsible for the observed corrosion inhibition effect given that they are comprised of mixtures of organic compounds.…”

Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ Using Ethanol Extract of <i>Funtumia elastica</i>

“…Electronic parameters for the simulation include restricted spin polarization using DND basis set and Perdew-Wang(PW) local correlation density functional. Details of the computation methods are presented in [38,39]. Figure 10 represents the electronic properties of conessine, 10(a) represents the optimized structure 10(b) shows the highest occupied molecular orbital 10(c) represents the lowest unoccupied molecular orbital (LUMO) 10(d) is the total electron density 10(e) shows the center for electrophilic attack and 8(f) is the centre for nucleophilic attack.…”