Hemigraphis colorata (HC) Leaves Extract as Effectual Green Inhibitor for Mild Steel Corrosion in 1M HCl

Abstract

The corrosion inhibitory effect of Hemigraphis colorata (HC) leaves extract on mild steel in 1M HCl was investigated using mass loss measurements, ultraviolet-visible(UV) spectroscopy, Fourier transform infrared spectroscopy(FT-IR), electrochemical impedance spectroscopy (EIS), and Tafel polarization techniques at the temperature range of 303K-323K. The optimum inhibition efficiency of HC extract at 303K, 313K, and 323K was found to be 90.2%,92.77%, and 93.73%, respectively, for the maximum concentration of the extract. This suggests that inhibition efficiency was found to increase with increasing concentration of the leaves extract at all the temperatures and increasing solution temperature. The adsorption process complied with a Langmuir adsorption isotherm. Polarization measurements suggest a mixed mode of corrosion inhibition. The activation energy and other thermodynamic parameters were calculated for the process of inhibition. The adsorbed invisible layer was investigated using scanning electron microscopy, which revealed better morphology of mild steel in extract presence. Using energy-dispersive X-ray spectroscopy, the effect of HC extract on the interfacial behavior of mild steel surface was analyzed.