Corrosion Inhibition of Mild Steel in Acidic Media using Caladium Tricolor Starch Extract: An Eco-Friendly Approach

Abstract

Caladium tricolor tuber starch (CTS) was extracted and used as corrosion inhibitor for mild steel in 0.5M HCl and 0.5M H2SO4 acid media respectively at various concentrations using the gravimetric technique. Results obtained shows that inhibition efficiency of the CTS inhibitor varied with time and concentration. Inhibition efficiency of caladium tricolor starch obtained ranged from 60% - 95% at 0.3g – 0.9g concentration in both acidic media. Maximum efficiency was obtained at concentration of 0.9g at 48 hours in 0.5M H2SO4. The highest inhibition efficiency obtained in HCl media was 90.03% at 0.9g/L concentration after 24 hours while 95.40% was obtained in H2SO4 media at 0.9 g/L after 48 hours, indicating CTS performed better in H2SO4 than in HCl. The mode of adsorption of the caladium tricolor starch followed the Langmuir isotherm exhibiting a Gibbs free energy value of −15.246KJ/mol, which indicates strong adsorption of the caladium tricolor starch molecules on the mild steel substrate.