Ethanolic extract of Chrysophyllum albidum leaves and peels as a green inhibitor for AISI 1015 carbon steel in 1 M H₂SO₄ solution

Abstract

The degradation of mild steel has been an issue of concern in most industries. Because of this challenge, mild steel (AISI 1015 carbon steel) was inhibited using ethanolic extract from leaves and peels of Chrysophyllum albidum (C. albidum) in 1 M H₂SO₄ was investigated using gravimetric (weight loss), gasometric and potentiodynamic polarization (PP) methods. Samples of mild steel were placed in an acidic medium and tested at different concentrations of extract. The PP experiment indicated that the inhibition efficiency (LE) of C. albidum ranges from 70.9-85.9% and 54.6-89.1%, for leaves and peels extract, respectively. The I.E increases with increase in concentration of the extracts due to the adsorption of their molecules on the mild steel surface. The leaves and peels 1.5 g/L extract inhibited mild steel sample exhibited a significant corrosion rate of 0.0821 mm/year and 0.0635 mm/year, respectively. The inhibitors exhibited mixed-type corrosion inhibition tendencies. Moreover, the weight loss test revealed that the inhibitors lower the corrosion rate of the steel samples. The adsorption ability of the extracts was approximated through the Langmuir isotherm. The correlation regression coefficients (R²) values of 0.9960 and 0.9981 were observed for the leaves and peels extracts, respectively. This study has shown that C. albidum extracts reduced the rate at which mild steel corrodes in an acidic medium. It is therefore recommended for application in acidic media.