Evaluation of the corrosion inhibition potentials of green-tip forest lily (<i>Clivia nobilis</i>) <i>leaves extract</i> on mild steel in acid media

Abstract

Plant extracts are excellent alternatives as corrosion inhibitors because of availability, low toxicity, biodegradability and low cost. In this study, corrosion tests were performed on mild steel to evaluate the effect of concentration of inhibitor, varying immersion period and temperature on the corrosion inhibition properties of Clivia nobilis leaves extract. This was done in H2SO4 and HCl acid solutions using weight loss and gasometric methods. From the weight loss results, corrosion rate and degree of surface coverage were evaluated and plotted as a function of inhibitor concentration at various immersion times. The volume of the cathodic hydrogen gas evolved was also plotted as a function of inhibitor concentration. The efficiency of inhibition in H2SO4 and HCl solutions were also compared. It was observed that corrosion inhibition efficiency increased with increasing concentration of Clivia nobilis leaf extract but not with prolonged immersion period. Experimental data obtained at 313 and 333K fitted the Freundlich and Langmuir isotherms, suggesting adsorption of Clivia nobilis leaves extract on the metal surface. Activation energy data described the interaction as electrostatic.

Adsorption and Inhibition Analysis of Aconitine and Tubocurarine Alkaloids as Eco-friendly Inhibitors of Pitting Corrosion in ASTM – A47 Low Carbon Steel in HCl Acid Environment

“…Comparing inhibition ). This could be due to the presence of more hetero-atoms (2N), pi bonds from double bonds, and benzene rings, including proper orientation of the molecular structure on metal during adsorption [15,[20][21][22].…”

“…In contrary to the result of the corrosion rate of metal at ambient temperature in the gravimetric analysis, the gasometric analysis showed increased corrosion rate and a slight decrease in inhibition efficiency as the temperature was increased accordingly. This is due to the high-temperature effects that bring about agitation and desorption of weakly bounded inhibitor molecules held on the low carbon steel surface by van der Waals forces of attraction rather than ionic bonding [13,22,[27][28][29][30]. This can also be possible because of the migration of segments of molecules or individual molecules (inhibitors) in jumps, from one place in a site to a vacant hole of the site [17,25,31].…”

Comparative evaluation of the adsorption of chromium (VI) by modified and unmodified mangrove leaf sorbents

“…Adsorption Isotherm: Adsorption isotherm describes the equilibrium relationship between the adsorbate in the solution and the adsorbate on the adsorbent at constant temperature (Ali Riza et al, 2007). Models such as those of Langmuir (equation 1) and Freundlich (equation 2) are widely employed to describe experimental sorption data (Cookey et al, 2018). Langmuir parameters (qmax and Kl) were calculated from the slope and intercept of the linear plot of Ce/qe versus Ce as depicted in equation 1.…”

Kinetics Consideration of Ethanol Leaves Extract of Costus Lucanusianus as Green Corrosion Inhibitor for Mild Steel and Aluminium in HCL Solution

“…Thus, implying that the inhibitors have the potential of influencing the incoming energy in the system resulting in higher potential energy and lower kinetic energy, hence breaking up the intermolecular force between the molecules, leading to a slower corrosion reaction rate Srinivasulu and Kasthuri (2017), Gadow and Motawea (2017). The negative values of ΔS indicate a decrease in the disorderliness of the system compared with the blank Azzaoui et al (2017) and therefore an increased orderliness in the system as a result of an orderly adsorption of the inhibitor molecules freely moving in the bulk solution onto the mild steel and aluminium metal surfaces which often indicates an associative mechanism in which both the molecules of the extracts and ions of the metals form a single activated complex, hence creating a better inhibition Cookey et al (2018) Figure 5 Transition state plot for mild steel and aluminium in different concentrations of ELECL…”