Inhibition of Mild Steel Corrosion by Aspilia africana in Acidic Solution

Abstract

This paper is a study of the inhibitive effect of Aspilia africana leaves extract on mild steel corrosion in 1.0 M hydrochloric acid (HCl) at room temperature and at 60oC. The leaves extract had shown good inhibition efficiency on the corrosion of mild steel with optimum values of 88.1% at room temperature and 91% at 60C. The Langmuir and Temkin isotherms were used to analyse the adsorption mechanism of the inhibitor-metal interaction. The Gibb's free energy of adsorption showed a spontaneous and mixed adsorption-physisorption and chemisorption. The deductions from the apparent activation energy and heat of adsorption calculations also confirmed a mixed adsorption mechanism.