The Use of Rubber leaf Extract as a Corrosion Inhibitor for Mild Steel in Acidic Solution

摘要

This work has explored the possibility of using plant extract as a corrosion inhibitor other than the use of conventional organic materials as corrosion inhibitor. Rubber leaf extract which contains the carbonyl groups, aromatic rings, and double bonds as indicated by the GCMS, phytochemical, and FTIR analysis is one of the good natural plant extract as corrosion inhibitor. Gravimetric method was used to determine the weight loss on surface of mild steel at various inhibitor concentrations in 0.1M HCl solution. The highest inhibition efficiency of 86% was achieved using the rubber leaf extract as inhibitor. Adsorption mechanism was investigated using Langmuir, Temkin, and Freundlich isotherms. Inhibitor adherence on the mild steel surface was spontaneous with the negative Gibb’s free energy value of -18.07kJ/mol obtained. The inhibitor was adsorbed on the mild steel surface through adsorption of the phytochemical components on the surface of mild steel which protects the metal surface from corroding. The corrosion rate decreases with increase in various inhibitor concentrations and exposure time studied.