Corrosion inhibition of mild steel using alkaloids and tannins extracts of Jatropha curcas in acidic media

Abstract

Corrosion inhibition of mild steel from Jatropha curcas stem bark was investigated using gravimetric method at 303K. The results showed that it contains 1.66% alkaloids and 1.53% tannins, these phytocompounds were found to inhibit corrosion process of mild steel in the test solutions and the inhibition efficiency depends on the concentration of alkaloids and tannins as well as the exposure time. The adsorption of both alkaloids and tannins on the mild steel was found to obey and Langmuir adsorption isotherms and this suggested that the inhibitor molecules have been spontaneously adsorbed onto the surface of mild steel through a physical adsorption mechanism. The inhibition efficiency is markedly higher in addition compared with that of tannins extracts. Corrosion inhibition is attributed to the spontaneous physical adsorption of the plant constituents on the surface of the mild steel.