Tragia plukenetii extract as an eco-friendly inhibitor for mild steel corrosion in HCl 1 M acidic medium

Abstract

A Tragia plukenetii (T. plukenetii) plant extract for use as a low-cost and efficient corrosion inhibitor for mild steel (MS) in 1 M HCl medium has been studied using various methods involving weight loss calculation, electrochemical impedance spectroscopy, and Tafel polarization. The maximum corrosion inhibition efficiency was found to be 88 % at 500 ppm. It was found that the T. plukenetii extract’s inhibition efficiency increased with the inhibitor concentration. The polarization measurement showed that the T. plukenetii plant extract acts as good mixed-type inhibitor. Thermodynamic investigations showed the change in enthalpy, entropy, and free energy. The adsorption mechanism of the extract was investigated using UV–Visible, FT-IR, Raman spectroscopy, and wide-angle X-ray diffraction studies. The inhibitor solution, investigated on the basis of the atomic absorption spectra for MS, revealed decreased dissolution of Fe in the presence of the plant extract. Surface analysis of the metal with and without the plant extract was carried out by using scanning electron microscopy and energy-dispersive X-ray spectroscopy.