Physical Science International Journal

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.