A comprehensive analysis of Arum dioscoridis plant leaf extract as a corrosion inhibitor for mild steel in 1 M HCl: Synthesis, characterization, surface analysis observations, experimental and DFT studies

Abstract

Background

Corrosion occurs wherever metal and its alloys exist. Protection of metals with corrosion inhibitor is a popular topic. Considering environmental concerns and human health, it is more favorable to use green corrosion inhibitors than traditional corrosion inhibitors. Methanol extract of Arum dioscoridis (AD) becomes a potential green corrosion inhibitor and it can be used in industrial areas.

Methods

Corrosion efficiency, corrosion behavior and corrosion mechanism of Arum dioscoridis leaf extract on mild steel (MS) are illuminated in 1 M HCl by Tafel curves, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), zero charge potential, structural and surface morphological analysis and density functional theory (DFT).

Significant findings

The extract function as mixed-type corrosion inhibitor with predominantly cathodic action. Inhibition efficiency was reached the value of 97 %. Polarization resistance is measured as 761 Ω cm² at 1000 ppm of AD. The high inhibition efficiency was attributed to phytochemicals in the AD extract. A high activation energy (70.34 kJ/mol) for inhibited solution than that of in blank solution (49.66 kJ/mol). Both physisorption and chemisorption are responsible for formation of a protective layer on MS surface to inhibit the electrochemical reactions. Optimized molecular structures in phytochemicals confirmed the inhibitive properties via DFT.