Application of ginger and grapefruit essential oil extracts on the corrosion inhibition of mild steel in dilute 0.5 M H2SO4 electrolyte

Admixture of ginger and grapefruit essential oils (GPP) were studied for their corrosion inhibition properties on mild steel (MS) in 0.5 M H2SO4 solution by potentiodynamic po-larization, open circuit potential measurement, electrochemical impedance spectroscopy, weight loss analysis and ATF-FTIR spectroscopy. Results from potentiodynamic polariza-tion shows GPP significantly reduced the corrosion of MS from 8.430 mm/y at 0% GPP concentration to values between 1.979 mm/y and 0.565 mm/y. The corresponding inhi-bition efficiency values ranged from 76.52% to 93.5% and corrosion current density from 1.88 x 10 -4 A/cm2 to 5.36 x 10 -5 A/cm2. GPP displayed mixed-type inhibition at all GPP concentrations studied. The OCP plot at 0% GPP initiated at -0.495V compared to -0.4 43V and -0.451V at 1% and 3.5% GPP. At 90 0 0s, the corresponding OCP values are -0.4 42V, -0.410V and -0.424V due to electropositive plot shift and passivation of MS surface at 1% and 3.5% GPP, though significant potential transients were present on the OCP plot at 1% GPP. The electrochemical impedance results indicate that the corrosion resistance of MS increased from 4.402 S2 cm2 to 99.318 S2 cm2 upon the addition of 3.5% GPP resulting in inhibition efficiency of 96%. Data from weight loss analysis shows decrease in corrosion rate from 184.48 mm/y to values between 8.94 mm/y and 6.25 mm/y. The corresponding inhibition efficiency values varies from 95.16% at 1% GPP to 96.61% at 3.5% GPP concentra-tion. The ATF-FTIR results confirm the adsorption of GPP molecules on the surface of the carbon steel electrode.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Automated summary

The corrosion inhibition properties of a mixture of ginger and grapefruit essential oils (GPP) on mild steel (MS) in 0.5 M H2SO4 solution were investigated. The results showed that GPP could effectively reduce the corrosion rate and current density of MS, with inhibition efficiency ranging from 76.52% to 93.5%.