Corrosion resistance of mild steel in 0.5 M H2SO4 solution by plant extract of Alkana tinctoria: Experimental and theoretical studies

Corrosion inhibition analysis and adsorption behaviour of Alkana tinctoria root extract for mild steel in 0.5 M H2SO4 solution has been inquired utilizing scanning electron microscopy (SEM), atomic force microscopy (AFM), weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and quantum chemical calculations. Electrochemical investigation and weight loss estimation say that the root extract of Alkana tinctoria shows the most extreme inhibition effectiveness up to 91.63% for mild steel at 500 mg/L (by weight) concentration in 0.5M H2SO4 solution at 298 K. The presence of Dihydroxytriangularicine, 7-Angeloylretronecine and Alkannin as major phytochemical constituents in the extract of Alkana tinctoria decreases the corrosion rate of mild steel in acidic media. The adsorption of this extract obeys the Langmuir adsorption isotherm. The effects generated from different investigations confirm that the root extract of Alkana tinctoria acts as a mixed type of inhibitor and forms a protective layer on the surface of mild steel. Due to the presence of hetero atoms and aromatic rings in the major compounds of Alkana tinctoria, it can serve as an effective corrosion inhibitor for mild steel corrosion in 0.5M H2SO4.