Performance of Terminalia Catappa Leaves Extract as Bio-Corrosion Inhibitor for Mild Steel in H₂SO₄ Solution

Terminalia catappa leaves extract has a high content of polyphenol compounds. Polyphenol compounds inhibit the corrosion rate for mild steel. This study aimed to assess the ability of terminalia catappa leaves extract to inhibit bio-corrosion on the surface of mild steel placed in a corrosive medium of 1M sulphuric acid, and to compare this with that of tannin and sodium phosphate. The method used was the loss of weight at temperatures of 313K, 333K and 353K. It found that the inhibition efficiency was susceptible to increased temperature. The efficiency of bio-corrosion inhibition of sodium phosphate> tannin>Terminalia catappa leaves extract; that is, the ability of Terminalia catappa leaves extract to inhibit bio-corrosion was relatively lower than that of tannin and sodium phosphate. Terminalia catappa leaves extract's inhibiting corrosion rate of mild steel was very good at 333K and 1250 ppm concentration, with an efficiency inhibition of 64%. The adsorption mechanism is a Langmuir isotherm, and the process is endothermic and spontaneous.