Inhibition of corrosion of mild steel in simulated oil well water by an aqueous extract of Daucus Carota (Carrot)

• S.C. Joycee¹, A.S. Raja¹, A.S. Amalraj² and S. Rajendran³

¹ PG and Research Department of Chemistry, G.T.N Arts College (Autonomous), Dindigul, 624 005, India
² PG and Research Department of Physics, Sree Sevugan Annamalai College, Devakottai, 630 303, India
³ Corrosion Research Centre, Department of Chemistry, St. Antony’s College of Arts and Sciences for Women, Dindigul, 624 005, India (Affiliated to Mother Teresa Women’s University, Kodaikanal, India)

Abstract: In recent years, researchers have shifted their focus towards eco-friendly corrosion inhibitors due to the detrimental effects of traditional ones. Plant extracts have shown effective corrosion inhibition properties, attributed to their diverse organic compounds, including terpenoids and flavonoids. This study examines the corrosion inhibition of mild steel in simulated oil well water (SOWW) with and without Zn²⁺ using Daucus carota (carrot) extract, employing the weight loss method. The findings indicate that the inhibition efficiency increases with higher concentrations of the inhibitor. The mechanisms behind the corrosion inhibition were explored through polarization studies and AC impedance spectroscopy. The polarization study indicates that the combination of Daucus carota extract and Zn²⁺ acts as a mixed-type inhibitor. This is supported by an increase in linear polarization resistance and a decrease in corrosion current. The formation of a protective layer on metal surface is evidenced by AC impedance spectra, which show increased charge transfer resistance and decreased double layer capacitance. FTIR spectroscopy characterizes the protective coating, confirming that the inhibitor interacts with ferrous ions on metal surface via the active component β-carotene. Scanning electron microscopy (SEM) was used to analyze surface morphology, and Vickers hardness tests revealed that the metal surface becomes harder in the presence of the inhibitor compared to its absence in the corrosive environment of SOWW. These results suggest potential applications in the petroleum industry, as Daucus carota extract could be incorporated into pipelines made of mild steel along with SOWW.

Keywords: corrosion inhibition, green inhibitor, mild steel, Daucus carota, electrochemical studies, Vicker hardness, carrot, SEM, AFM

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 269-287
doi: 10.17675/2305-6894-2025-14-1-17

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