Abstract:
The corrosion inhibition studies of ethanolic extract of Chrysophyllum albidum leaves (E.CA) and Sorghum arundinaceum straw (E.SA) on mild steel were assessed using weight loss method, Potentio-dynamic polarization method , Atomic Absorption Spectroscopy (AAS), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy/ Electron Dispersive X-ray Spectroscopy (SEM-EDX). The ethanolic extract of both samples had higher inhibition efficiency than the aqueous extract. Preliminary investigation of phytochemicals reveals that the extracts contain flavoniods, terpenoids, saponins. The effects of varying concentration of the inhibitors, immersion time, and temperature on mild steel corrosion in 5M HCl solution were examined. The results showed that the inhibition efficiency (I.E %) increases with increase in concentration of the extracts up to 83.24% and 71.62% for E.CA and E.SA respectively. However, the inhibition efficiency decreases with increase in temperature for both extracts. The kinetics studies of the data followed a first order reaction. Thermodynamics studies revealed that the corrosion inhibition study was endothermic and spontaneous. Experimental data were fitted to Langmuir, Freundlich and Temkin Adsorption isotherms. AAS results showed a decrease in the dissolution of Fe in both extracts compared to the blank. Potentiodynamic polarization curve reveals the extracts acts as a mixed inhibitor.
