Corrosion inhibition characteristics of Plukenetia conophora shell extract on corrosion of pipeline steel in acidic solution

Abstract

The ability of aqueous extract Plukenetia Conophora to inhibit pipeline steel corrosion in 0.5 M HCl acid was investigated using gravimetric and electrochemical techniques. Fourier transform infra-red spectroscopy (FT-IR technique) was used to study the corrosion surface film of the pipeline steel. The result shows that the corrosion rate decreased with increased extract concentration. The values from electrochemical impedance  spectroscopy and weight loss measurement were consistent validating the inhibitory capacity of the extract. The Tafel plot revealed that the  inhibitor acted as mixed class inhibitor. The FTIR spectra showed that the inhibitor molecules were deposited on the surface of electrode. The adsorption of inhibitor molecules on the steel surface was in accordance with the Temkin adsorption isotherm.

Keywords: Walnut shell, EIS, PDP, Corrosion, GC-MS.