Adsorption and corrosion inhibition properties of ricinus communisin acid solutions

Abstract

The castor plant, with its potential phytochemical constituents, presents an opportunity to serve as a green corrosion inhibitor.This study aims to evaluate the adsorption and corrosion inhibition properties of castor plant extracts on mild steel in acidic media. Leaves of the castor oil plant were sun dried using both sunlight and an oven. The dried leaves were then ground to increase the surface area. Solvent extraction was carried out using ethanol as a solvent and filtered. The extract obtained in ethanol solvent was concentrated, distilling off the solvent. Solutions of the extract were prepared in the concentrations of (50,25,10) v/v per cent, with the respective corrodents as solvent that is 0.5M H2SO4 and 1M HCL. Weighed mild steel coupons were separately immersed in 250 mL open beakers containing 1.0 M HCl and 0.5 M H2SO4. Also, mild steel coupons were separately immersed in 250 mL open beakers containing 1.0 M HCl and 0.5M H2SO4 with various concentrations of the castor oil leaf extracts. After 4 hours the coupons were taken out, immersed in acetone, dried and reweighed. The weight loss was calculated as the difference between the initial weight and the weight after the removal of the corrosion product. The experimental readings were recorded to be used in calculating corrosion rate and the inhibition efficiencies The corrosion rate of mild steel decreased with increasing extract concentration in both acidic environments confirming the formation of a protective layer by the extract molecules on the steel surface. The gravimetric method revealed that the castor plant extract exhibited promising corrosion inhibition efficiency (IE) across different concentrations in both 0.5M H2SO4 and 1M HCl The effect of temperature on corrosion rates with and without the castor plant extract provided valuable insights into the adsorption behavior and potential mechanism of inhibition.