Investigation of Citrus aurantiifolia Leaves Extract as Corrosion Inhibitor for Mild Steel in 1 M HCL

Abstract

The inhibition efficiency of acid extract of leaves of Citrus aurantiifolia [CAL] plant on the corrosion of mild steel in 1 M HCl was investigated by weight loss measurements and electrochemical studies. The corrosion rate of mild steel and the inhibition efficiencies of the extract were calculated. The results obtained show that the extract could serve as an effective inhibitor for the corrosion of mild steel in HCl media. Inhibition was found to increase with increasing concentration of the plant extract. The inhibitive action of plant extract is discussed on the basis of adsorption of stable complex at the mild steel surface. Theoretical fitting of different isotherms, Langmuir, Temkin, Freundlich, Frumkin, Flory-Huggins and the kinetic thermodynamic model, were tested to clarify the nature of adsorption. Polarisation curves revealed that this inhibitor act as a mixed type inhibitor and the inhibition efficiency of up to 97.51% can be obtained. The surface analysis study confirms the corrosion of mild steel and its inhibition by the inhibitor CAL.

Determination of Adsorption Isotherm model best fit for methanol leaf extract of Securinega virosa as corrosion inhibitor for corrosion of mild steel in HCl

“…The parameter, x, of Flory-Huggins isotherm indicates the number of active sites occupied by one inhibitor molecule or number of water molecules replace by one molecule of the adsorbate. Value of x > 1 implies that one inhibitor molecule replaces more than one water molecule on the adsorbent surface [29]. The values of x (Table 2) obtained are less than one except at 315 K, meaning more than one molecules of the inhibitor occupied one active site during the inhibition process, except at 315 K. The facts that x values are not clearly defined for this extract means that the data do not properly fit into this isotherm model.…”

"Corrosion Inhibition Efficiency of Human Black Hair Sample for Mild Steel in Phosphoric Acid "

“…For all inhibitor concentrations, βa is lesser than βc indicating that yet the inhibition is under mixed control, the effect of the inhibitor on the cathodic polarization is distinct than on the anodic polarization. 19 was calculated using the Stern-Geary Equation-6 was used to calculate the polarization resistance (Rp) from Tafel extrapolation method . The inhibition efficiency was determined by the formula (1) and (2) and are tabulated in Table-6.…”

Preparation of novel compounds, characterization and studying experimentally and theoretically as inhibitors through thermodynamic and quantum chemistry

“…The increase of activation energies values signify that the adsorption which has been occurred is physical adsorption. The change in values of Ea at inhibitors presence is not at the same pace due to the modification of mechanism of corrosion process and its decrease [38,45,46]. The ΔG° values listed in Table 4 are positive and increase with increasing both of concentration and temperature.…”